--- title: Release Notes for Couchbase Server 7.6 description: Couchbase Server 7.6.x introduces multiple new features and fixes, as well as some deprecations and removals. pubDate: 2026-08-17T09:53:44.266Z antora: editUrl: https://github.com/couchbase/docs-server/edit/release/7.6/modules/release-notes/pages/relnotes.adoc xref: xref:7.6@server:release-notes:relnotes.adoc[] --- [Consult the llms.txt file for a full list of contents](/llms.txt) [View original HTML](/server/7.6/release-notes/relnotes.html) # Release Notes for Couchbase Server 7.6 > [!WARNING] > Data consistency issue for buckets using Magma storage engine > > If you're using Magma buckets and upgrading from any release prior to 7.6.7, then follow the upgrade instructions as described in [MB-67762](https://jira.issues.couchbase.com/browse/MB-67762) ## [](#release-7612)Release 7.6.12 (July 2026) Couchbase Server 7.6.12 was released in July 2026\. This maintenance release contains fixes to issues. ## [](#fixed-issues)Fixed Issues ### [](#xdcr)XDCR | Issue | Description | Resolution | | -------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | -------------- | | [MB-71258](https://jira.issues.couchbase.com/browse/MB-71258/) | When pausing or deleting a replication that is replicating to or from a cluster that recently underwent a failover and needs to rollback to 0, there could be a race condition that causes the goroutines to be stuck indefinitely. This has now been fixed. | Issue resolved | ### [](#query-service)Query Service | Issue | Description | Resolution | | -------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------ | -------------- | | [MB-71824](https://jira.issues.couchbase.com/browse/MB-71824/) | This fix solves the issue whereby hibernated process failed to wake up. The issue manifested as stuck REST API requests. | Issue resolved | ### [](#analytics-service)Analytics Service | Issue | Description | Resolution | | -------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------- | | [MB-71453](https://jira.issues.couchbase.com/browse/MB-71453/) | Queries that combine a LIMIT clause with an index-nested-loop join (specified via the /\*+ indexnl \*/ hint) and include additional filter conditions on the joined collection may return incorrect results, since these conditions are not fully evaluated before the LIMIT is applied. | Issue resolved | ## [](#release-7611)Release 7.6.11 (April 2026) Couchbase Server 7.6.11 was released in April 2026\. This maintenance release contains fixes to issues. ## [](#fixed-issues-2)Fixed Issues ### [](#cluster-manager)Cluster Manager | Issue | Description | Resolution | | -------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------- | | [MB-70577](https://jira.issues.couchbase.com/browse/MB-70577/) | Client certificate authentication for views was fixed (broken in 7.6.4) | Issue resolved | | [MB-70951](https://jira.issues.couchbase.com/browse/MB-70951/) | The following stats were reported twice by the /metrics REST API. This has been corrected to only report each once. cm\_rest\_request\_enters\_total{} cm\_rest\_request\_leaves\_total{} | Issue resolved | ### [](#xdcr-2)XDCR | Issue | Description | Resolution | | -------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------ | | [MB-70512](https://jira.issues.couchbase.com/browse/MB-70512) | DELETE returns a 400 error code | XDCR now returns a 404 status code if a resource is not found, for replication and remote cluster reference-related REST APIs. | | [MB-70906](https://jira.issues.couchbase.com/browse/MB-70906/) | Due to rare race conditions, Backfill Manager could be stuck due to deadlock. | Issue resolved | | [MB-71034](https://jira.issues.couchbase.com/browse/MB-71034/) | In rare circumstances when a replication is deleted and recreated in short succession, stale checkpoints that are not slow to be cleaned could lead to repeated pipeline restarts. | Issue resolved | ### [](#query-service-2)Query Service | Issue | Description | Resolution | | -------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | -------------- | | [MB-70543](https://jira.issues.couchbase.com/browse/MB-70543/) | Execution of a scope-level UDF (user-defined function) may fail and get Invalid Function error under the following conditions: Running Couchbase Server version 7.6.0 through 7.6.10. A query node is starting. The query node is NOT being upgraded from an earlier version (for example, 7.2) A scope-level UDF was already present (created before the query node started) A call to execute the scope-level UDF is issued against the query node shortly after the query node started. The issue has been fixed in Couchbase version 7.6.11. | Issue resolved | | [MB-70745](https://jira.issues.couchbase.com/browse/MB-70745/) | A restore may fail under the following conditions: Couchbase version 7.6.0 through 7.6.10 CBO (Cost-Based Optimizer) was enabled An index exists where one of the index keys contains '::', for example, SPLIT(, "::") UPDATE STATISTICS (or ANALYZE) has been run on the index a backup was taken after UPDATE STATISTICS was run a restore was attempted with the backup The issue has been fixed in 7.6.11. | Issue resolved | ## [](#release-7610)Release 7.6.10 (February 2026) Couchbase Server 7.6.10 was released in February 2026\. This maintenance release contains fixes to issues. ## [](#fixed-issues-3)Fixed Issues ### [](#cluster-manager-2)Cluster Manager | Issue | Description | Resolution | | -------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------- | | [MB-69026](https://jira.issues.couchbase.com/browse/MB-69026/) | Addressed an issue with stuck rebalance email alerts in Couchbase Server. This fix resolves problems observed when "Require encryption (TLS)" was configured, causing alert failures. | Issue resolved | | [MB-69650](https://jira.issues.couchbase.com/browse/MB-69650/) | A problem was introduced in 7.6.2 where the presence of a Cloud Native Gateway in the cluster would cause issues for services connecting to the cluster manager. The presence of Cloud Native Gateway no longer causes these issues. | Issue resolved | | [MB-70441](https://jira.issues.couchbase.com/browse/MB-70441/) | The upgrade to Erlang version 26 introduced a change in behavior which requires peer certification when TLS is being used for Alert emails. The peer certification introduced with the changes for this ticket uses the trusted CA certificates provided by the operating system. | Issue resolved | ### [](#data-service)Data Service | Issue | Description | Resolution | | -------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------- | | [MB-54274](https://jira.issues.couchbase.com/browse/MB-54274/) | The recent builds of various Couchbase components incorporate a change in the kv\_engine to modify the handling of temporary items. These items, whether initially created or deleted, are no longer removed immediately from the HashTable. The primary focus is on ensuring better handling and management of temporary items, enhancing system stability and performance. These updates are part of ongoing improvements committed to optimizing the kv\_engine and its interactions within the Couchbase ecosystem. | Issue resolved | ### [](#xdcr-3)XDCR | Issue | Description | Resolution | | -------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------- | | [MB-70294](https://jira.issues.couchbase.com/browse/MB-70294/) | Filter Expressions referencing only the document keys are now applicable on deletions and expirations using the new filterDeletionsWithExpression and filterExpirationsWithExpression replication settings via the REST API. | Issue resolved | ### [](#query-service-3)Query Service | Issue | Description | Resolution | | -------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------- | | [MB-68969](https://jira.issues.couchbase.com/browse/MB-68969/) | With multi-collection indexes that contained fields with include in \_all setting enabled - there was a possibility for false positives to show up for field agnostic (composite field) queries. This has been addressed by denying the sargability for such indexes. Addressed an issue where fields not belonging to a particular keyspace were being included in multi-collection indexes. Addressed a bug that could influence composite field (\_all) availability based on the order in which fields were processed. | Issue resolved | | [MB-69081](https://jira.issues.couchbase.com/browse/MB-69081/) | To retrieve a document's expiration, the user had to specify the sub-path explicitly, i.e META().expiration. A call to the META() function without the sub-path would return the default expiration value 0 always which was incorrect. Now, when a user's query invokes META() function without explicitly specifying the sub-path the document's expiration value is returned. | Issue resolved | | [MB-69083](https://jira.issues.couchbase.com/browse/MB-69083/) | Problem: A query may return an incorrect result under the following conditions: query contains one or more joins one of the joins involves a sub-query (FROM clause subquery) the FROM clause sub-query has a GROUP BY and/or aggregates the FROM clause sub-query can take advantage of index group/aggregate pushdown (this requires an appropriate secondary index) CBO is ON, and UPDATE STATISTICS has been run on all keyspaces/indexes involved | Issue resolved | | [MB-69387](https://jira.issues.couchbase.com/browse/MB-69387/) | The auto-reprepare feature is available in this release. It is an opt-in feature that automatically re-prepares a prepared statement before execution if any GSI changes (such as indexes being created or dropped) have occurred since the statement's plan was last created. This allows prepared statements to adopt better suited indexes in their plans. Enable this feature by setting bit 23 (0x800000 or 8388608) of the n1ql-feat-ctrl Query setting. Capella users should contact support to opt in. | Issue resolved | | [MB-69955](https://jira.issues.couchbase.com/browse/MB-69955/) | CYCLE was added as a KEYWORD for RECURSIVE WITH's CYCLE sub-clause. This causes a syntax error when a path or sub-path's case-insensitive identifier is named cycle when users upgraded to a version that supported the recursive with feature [WITH recursive clause](https://docs.couchbase.com/server/current/n1ql/n1ql-language-reference/with-recursive.html) This is now handled by allowing cycle keyword as a permitted identifier. | Issue resolved | | [MB-70112](https://jira.issues.couchbase.com/browse/MB-70112/) | When a prepared request is made with the auto\_execute request parameter set as true, the request would incorrectly error out with error: Unrecognizable prepared statement - cause: JSON unmarshalling error: auto\_execute did not produce a prepared statement In this release the server silently ignores the auto\_execute request parameter when the request is a prepared request. | Issue resolved | ### [](#index-service)Index Service | Issue | Description | Resolution | | -------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------- | | [MB-69934](https://jira.issues.couchbase.com/browse/MB-69934/) | Updated chronology for certain storage API calls to avoid rare corner case of shard metadata mismatch. | Issue resolved | | [MB-69952](https://jira.issues.couchbase.com/browse/MB-69952/) | Prior to this release, building a new GSI index on a collection could take an extended period of time in certain scenarios. The indexer builds a new index using a dedicated DCP stream and later merges it into the common DCP stream that processes incremental mutations. If mutation processing for the new index lagged behind incremental mutation processing, the DCP stream merge could be significantly delayed. This release introduces a mechanism to detect such imbalances and dynamically adjust the rate of incremental mutation processing to facilitate faster stream merging. | Issue resolved | ### [](#search-service)Search Service | Issue | Description | Resolution | | -------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------- | | [MB-68969](https://jira.issues.couchbase.com/browse/MB-68969/) | With multi-collection indexes that contained fields with include in \_all setting enabled - there was a possibility for false positives to show up for field agnostic (composite field) queries. This has been addressed by denying the sargability for such indexes. Addressed an issue where fields not belonging to a particular keyspace were being included in multi-collection indexes. Addressed a bug that could influence composite field (\_all) availability based on the order in which fields were processed. | Issue resolved | | [MB-70388](https://jira.issues.couchbase.com/browse/MB-70388) | The docvalues for geopoint fields were not being set internally. This meant that the values were computed on demand for every query. | Issue resolved. | ### [](#tools)Tools | Issue | Description | Resolution | | -------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | -------------- | | [MB-70255](https://jira.issues.couchbase.com/browse/MB-70255/) | Fixes bug where buckets with cross-cluster versioning enabled ([XDCR enable cross cluster versioning](https://docs.couchbase.com/server/current/learn/clusters-and-availability/xdcr-enable-crossclusterversioning.html) ) would cause a merge to fail | Issue resolved | ## [](#release-769)Release 7.6.9 (January 2026) Couchbase Server 7.6.9 was released in January 2026\. This maintenance release contains fixes to issues. ## [](#fixed-issues-4)Fixed Issues ### [](#eventing-service)Eventing Service | Issue | Description | Resolution | | ----------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------- | | [MB-69576](https://jira.issues.couchbase.com/browse/MB-69576/) [MB-70174](https://jira.issues.couchbase.com/browse/MB-70174/) | An issue existed with the basic keyspace GET operator in eventing functions where accessing valid documents from the KV bucket incorrectly returned undefined values. This caused the functions to be stuck in a deploying → deployed → deploying loop. | Issue Resolved | ## [](#release-768)Release 7.6.8 (November 2025) Couchbase Server 7.6.8 was released in November 2025\. This maintenance release contains fixes to issues. > [!WARNING] > Due to a current issue, we advise not upgrading to 7.6.8 if using eventing basic accessors. ## [](#fixed-issues-5)Fixed Issues ### [](#cluster-manager-3)Cluster Manager | Issue | Description | Resolution | | -------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------- | | [MB-67106](https://jira.issues.couchbase.com/browse/MB-67106/) | **Metric Rename – Cache Miss Ratio → Get Miss Ratio**The _Cache Miss Ratio_ metric name suggested it measured memory or disk caching performance. In practical instances, as of version 7.6.2, it was redefined to measure the proportion of read (get) operations that fail because the requested key is not present in the bucket at all. To eliminate confusion, the metric has been renamed to **Get Miss Ratio**. | Issue resolved | | [MB-67758](https://jira.issues.couchbase.com/browse/MB-67758/) | Prior to the 7.6.8 release, the auto-failover pop up alerts, as documented in [Saving and Testing the Alert Configuration](https://docs.couchbase.com/server/current/manage/manage-settings/configure-alerts.html#saving-and-testing-the-alert-configuration) did not work. This has been fixed. | Issue resolved | ### [](#data-service-2)Data Service | Issue | Description | Resolution | | -------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------- | | [MB-66876](https://jira.issues.couchbase.com/browse/MB-66876/) | The magma\_min\_value\_block\_size\_threshold has been adjusted to INT\_MAX for version 7.6.x, ensuring that block compression applies consistently for documents larger than 64 KiB. This change is not required for version 8.0.0 due to differences in configuration management. Couchbase recommends that if magma\_per\_document\_compression\_enabled is set to false, magma\_min\_value\_block\_size\_threshold should also be set to infinity to maintain compression behavior. This resolves an issue with the Magma storage engine not compressing documents during persistence, which has been addressed in recent builds. The changes are confirmed and the ticket is closed after reviewing the code updates. | Issue resolved | | [MB-67106](https://jira.issues.couchbase.com/browse/MB-67106/) | **Metric Rename – Cache Miss Ratio → Get Miss Ratio**The _Cache Miss Ratio_ metric name suggested it measured memory or disk caching performance. In reality, as of version 7.6.2, it was redefined to measure the proportion of read (get) operations that fail because the requested key is not present in the bucket at all. To eliminate this confusion, the metric has been renamed to **Get Miss Ratio**. | Issue resolved | ### [](#xdcr-4)XDCR | Issue | Description | Resolution | | -------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | -------------- | | [MB-66649](https://jira.issues.couchbase.com/browse/MB-66649/) | When modifying filter expressions or mapping configurations (explicit/migration), race conditions may prevent proper replication from the source. This can result in source bucket documents failing to replicate to the target bucket. To address this issue, the system now displays an alert when detecting replication resuming from stale checkpoints. This alert notifies users to delete and recreate the affected replication. IMPORTANT: Do not dismiss this alert by pausing and resuming the replication, as this will hide the warning without resolving the underlying issue. | Issue resolved | ### [](#query-service-4)Query Service | Issue | Description | Resolution | | -------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------- | | [MB-66703](https://jira.issues.couchbase.com/browse/MB-66703/) | Added a plan version to prepared statements and logic to trigger reprepare when outdated plans are detected. This avoids duplicate OFFSET execution in mixedmode clusters due to changes in ORDER BY and LIMIT/OFFSET handling. | Issue resolved | | [MB-67849](https://jira.issues.couchbase.com/browse/MB-67849/) | The recent builds of Couchbase Server versions 7.2.7 through 8.1.0 and Enterprise Analytics 2.1.0 include updates from the go\_json library to address int64 overflow issues reported under MB-67849\. The updates involve implementing proper checks for int64 overflow to properly represent large numbers (greater than 263or less than -263). | Issue resolved | ### [](#index-service-2)Index Service | Issue | Description | Resolution | | ------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [MB-66434](https://jira.issues.couchbase.com/browse/MB-66434) | In certain scenarios where shard affinity has been toggled on or off, or a previous rebalance was canceled midway, the Alternate Shard IDs for some replicas may be reset. During a later rebalance where shard affinity is enabled and optimise index placement is turned off, the replica repair process assigns a shard to the lost replica based on the Alternate Shard ID of its surviving counterpart. The existing replicas whose Alternate Shard IDs were reset are also re-assigned the same Alternate Shard ID. However, since index movement is turned off (due to optimise index placement being off), these replicas remain on their original nodes. As a result, the same Alternate Shard ID can end up being present on multiple nodes. This violates the planning invariant that requires each Alternate Shard ID exists on one node only. Violation of this invariant led to a panic during rebalance. | This complex condition was considered in the later stages of planning, to ensure that whenever non-moving indexes are also assigned the Alternate Shard ID, they are not to be considered in the planning of moving indexes. This will prevent the occurrence of panics during a rebalance. | ### [](#tools-2)Tools | Issue | Description | Resolution | | -------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------- | | [MB-60676](https://jira.issues.couchbase.com/browse/MB-60676/) | Previously in clusters with the backup service running on multiple nodes it was possible for more than one task on a repo to be attempted at the same, causing all but one of these tasks to fail. If multiple tasks are scheduled to run at the same time, we now skip all but the first one. | Issue resolved | ## [](#release-767)Release 7.6.7 (August 2025) Couchbase Server 7.6.7 was released in August 2025\. This maintenance release contains fixes to issues. ## [](#fixed-issues-6)Fixed Issues ### [](#storage-engine)Storage Engine | Issue | Description | Resolution | | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------ | | [MB-67762](https://jira.issues.couchbase.com/browse/MB-67762) | There is an integer overflow bug in buckets using the Magma storage engine. This bug can potentially cause a subset of mutations to become invisible to read operations after approximately 500 billion to 2 trillion mutations per bucket. | For details, please refer to [MB-67762](https://jira.issues.couchbase.com/browse/MB-67762) | ## [](#release-7-6-6-may-2025)Release 7.6.6 (May 2025) For detailed information on new features and enhancements, see [What's New in Version 7.6](../introduction/whats-new.md). ### [](#fixed-issues-766)Fixed Issues Couchbase Server 7.6.6 was released in May 2025\. This maintenance release contains fixes several for known issues. This release contains the following fixes: #### [](#storage-engine-2)Storage Engine | Issue | Description | Resolution | | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | [MB-64353](https://jira.issues.couchbase.com/browse/MB-64353) | Hard failover of ephemeral buckets could lead to the rollback of DCP clients back to 0\. There is currently no work-around for this, and currently the only solution is to upgrade to a version with the fix. 7.6.3 is the oldest release with the fix. **Details:** Hard failover of an ephemeral bucket. Replica promoted to active. DCP client reconnects to the new active. DCP clients rollback to zero and have to re-stream all the mutations from the new active. | Issue resolved. | | [MB-64742](https://jira.issues.couchbase.com/browse/MB-64742) | An issue in the plasma tracking stats flagged a stale recovery point in the recovery log as valid data. This made the log cleaning run slowly at a low mutation rate, and therefore, unable to trim the recovery point history effectively. At a higher mutation rate, the mutations alone could push the fragmentation ratio high enough to start the log cleaner, and therefore, was able to trim rp history despite the issue with tracking stats. | We mark the latest version of the recovery point that exists in both the recovery log and the data log. This effectively means that plasma will keep the recovery point history list to 1 in the recovery log. In addition, the plasma tracking stats are fixed such that it no longer treats the older recovery point as valid data in the recovery log.This allows the log cleaner to run even at a low mutation rate. | | [MB-65738](https://jira.issues.couchbase.com/browse/MB-65738) | An optimization to increase the memory residency of active plasma items caused an issue. In-memory compression of plasma pages under certain conditions may result in high CPU usage with this optimization.Prior to Release 7.6.0, this issue will not occur as this optimization was not present. | Issue resolved. | #### [](#data-service-3)Data Service | Issue | Description | Resolution | | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------- | | [MB-63827](https://jira.issues.couchbase.com/browse/MB-63827) | DCP connection metrics for connection names that do not conform to the server format are not aggregated by connection type when exposing to Prometheus, potentially producing a large number of time series. | The metrics are aggregated and exposed with connection\_type="\_unknown". | #### [](#xdcr-5)XDCR | Issue | Description | Resolution | | ------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------- | | [MB-62309](https://jira.issues.couchbase.com/browse/MB-62309) | Tombstones were not replicated if the binary filter is turned on. | Issue resolved. | | [MB-64563](https://jira.issues.couchbase.com/browse/MB-64563) | If users do not want the replication to be automatically deleted upon either source or bucket deletion and/or recreation, users can set the skipReplSpecAutoGc replication setting to true upon replication creation. In the situation that the replication would have been deleted, it will have been automatically paused instead, and a persistent UI error message logged to be viewed. Users are expected to manually execute the recovery action by deleting the replication and re-creating a newer one, if necessary. | Issue resolved. | #### [](#query-service-5)Query Service | Issue | Description | Resolution | | ------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------- | | [MB-65055](https://jira.issues.couchbase.com/browse/MB-65055) | In a cluster with multiple query nodes, performing a rolling upgrade to version 7.6.xfrom an earlier version (such as 7.2) may cause prepared statements containing a WITH clause to malfunction on the upgraded query node. | Issue resolved. | #### [](#index-service-3)Index Service | Issue | Description | Resolution | | ------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------- | | [MB-65012](https://jira.issues.couchbase.com/browse/MB-65012) | When shard affinity is enabled, the indexer internally maps all replicas of an index to an alternateID. If such an alternateID exists on a node outside the list of nodes, instead of preventing replica creation, the system creates a new replica with the same alternateID on different nodes. This leads to rebalance failures on the affected nodes. | When ALTER INDEX is used with the replica\_count action, do not allow the nodes clause when shard affinity is enabled | #### [](#search-service-2)Search Service | Issue | Description | Resolution | | ------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------- | | [MB-63246](https://jira.issues.couchbase.com/browse/MB-63246) | A Couchbase cluster upgrade to 7.6.2 caused data ingestion failure for legacy indexes using gocouchbase. A gocbcore\-specific check in [here](https://github.com/couchbase/cbft/blob/f81ec8920f9b022f7d605feee1907eb4c664379a/pindex%5Fbleve.go#L2374) is incompatible with the gocouchbase feed, resulting in ingestion errors. | Issue Resolved. | ## [](#known-issues-766)Known Issues ### [](#query-service-6)Query Service | Issue | Description | Workaround | | ------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | [MB-64966](https://jira.issues.couchbase.com/browse/MB-64966) | Scope level user-defined functions, sequences, and histogram data are stored in bucket/\_system/\_query collection. Flushing the bucket will delete the scoped UDF entries. When the UDFs are executed, it will work until the UDFs are evicted from the cache. After that, it will always result in an error. Sequences metadata is also stored in bucket/\_system/\_query collection. FLUSHing the bucket will delete the entries. When executed, sequences will return errors once evicted from the cache. \`FLUSH\`ing the bucket will also delete statistics data stored in the \`bucket/\_system/\_query collection. By using stale statistics stored in the cache, a non-optimal plan could be generated. | For user-defined functions, you can do one of the following: Recreate the scoped user-defined functions after the FLUSH. Use global UDFs instead of scoped UDFs. (Global UDFs are not stored in the \_query collection.) Create scoped UDFs on the bucket that does not have FLUSH enabled and then reference them via a fully qualified name (bucket.scope.UDFname). For sequence metadata: After the FLUSH, recreate the sequence, or Create sequences on the bucket that does not have FLUSH enabled and then reference them via a fully qualified name (bucket.scope.UDFname). For statistical data, rerun UPDATE STATISTICS on all the indexes on every scope and collections in the bucket that was flushed. | ## [](#release-7-6-5-january-2025)Release 7.6.5 (January 2025) Couchbase Server 7.6.5 was released in January 2025\. This maintenance release contains fixes several for known issues. For detailed information on new features and enhancements, see [What's New in Version 7.6](../introduction/whats-new.md). ### [](#fixed-issues-765)Fixed Issues This release contains the following fixes: #### [](#data-service-4)Data Service | Issue | Description | Resolution | | ------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [MB-64353](https://jira.issues.couchbase.com/browse/MB-64353) | Hard failover of ephemeral buckets could lead to the rollback of DCP clients back to zero. | Fixed in version 7.6.3. Upgrading to 7.6.5 will enable the fix. | | [MB-64742](https://jira.issues.couchbase.com/browse/MB-64742) | A bug in the plasma tracking statistics incorrectly marked stale recovery points in the recovery log as valid data. This caused two problems: At low mutation rates, the log cleaning process ran slowly and couldn't effectively trim recovery point history. At higher mutation rates, the system worked around this issue because mutations would increase the fragmentation ratio enough to trigger the log cleaner, which could then trim recovery point history despite the tracking statistics bug. | The system now marks only the latest recovery point that exists in both the recovery log and data log. This change effectively limits the recovery point history list to a single entry in the recovery log. The plasma tracking statistics have been fixed to correctly identify older recovery points as stale data in the recovery log. These improvements allow the log cleaner to run efficiently even at low mutation rates. | #### [](#query-service-7)Query Service | Issue | Description | Resolution | | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------- | | [MB-64684](https://jira.issues.couchbase.com/browse/MB-64684) | An issue occurred when an inline user-defined function (UDF) included a query with a nested Array construct, and the innermost Array construct referred to both: a UDF argument, and the binding variable of an outer ARRAY construct, Then the UDF creation or execution could fail. | Issue resolved | #### [](#search-service-3)Search Service | Issue | Description | Resolution | | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | [MB-64652](https://jira.issues.couchbase.com/browse/MB-64652) | An issue in versioning caused an online upgrade-rebalance operation to fail on account of a planning algorithm improvement. The bug would also impact the failover-recovery online upgrade path. This issue only surfaced when an upgrade was attempted over a system with search indexes from 7.6.\[0–3\] to 7.6.4. | The issue has been resolved in version 7.6.5. Our recommendation is to avoid the issue by moving directly to this version. | | [MB-64764](https://jira.issues.couchbase.com/browse/MB-64764) | If an index was created during rebalance, and the rebalance was stopped before plans were computed for that index, then no plans or partitions were created for the index until a subsequent rebalance was completed. In 7.6.4 we introduced a change to compute the plans for indexes created during a rebalance even when the rebalance stops midway. This inadvertently caused a regression where a subsequent rebalance could get stuck and fail continuously on timeouts. | In 7.6.5 we reverted the change: if the user aborts an ongoing rebalance, then plans for an index introduced during the operation may not be deployed until a subsequent rebalance operation is triggered and completed. | ### [](#known-issues-765)Known Issues This release contains the following known issues: #### [](#query-service-8)Query Service | Issue | Description | Workaround | | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | [MB-64966](https://jira.issues.couchbase.com/browse/MB-64966) | Scope level user-defined functions (UDFs), sequences, and histogram data are stored in the bucket/\_system/\_query collection. FLUSHing the bucket will delete the scoped UDF entries. When the UDFs are executed, it will work until the UDFs are evicted from the cache. After that, the execution will always result in an error. Sequences metadata is also stored in the bucket/\_system/\_query collection. FLUSHing the bucket will delete the entries. When executed, sequences will return errors once evicted from the cache. FLUSHing the bucket will also delete statistics data stored in the bucket/\_system/\_query collection. By using stale statistics stored in the cache, a non-optimal plan could be generated. | For user-defined functions, you can do one of the following: Recreate the scoped user-defined functions after the FLUSH. Use global UDFs instead of scoped UDFs. (Global UDFs are not stored in the \_query collection.) Create scoped UDFs on the bucket that does not have FLUSH enabled and then reference them via a fully qualified name (bucket.scope.UDFname). For sequence metadata: After the FLUSH, recreate the sequence, or Create sequences on the bucket that does not have FLUSH enabled and then reference them via a fully qualified name (bucket.scope.UDFname). For statistical data, rerun UPDATE STATISTICS on all the indexes on every scope and collections in the bucket that was flushed. | ## [](#release-7-6-4-december-2024)Release 7.6.4 (December 2024) Couchbase Server 7.6.4 was released in December 2024\. This maintenance release contains new features and fixes several known issues. For detailed information on new features and enhancements, please see [What's New in Version 7.6](../introduction/whats-new.md). ### [](#deprecated-platforms)Deprecated Platforms Windows 10 is deprecated in Couchbase Server 7.6.4\. A future version will remove support for this operating system. ### [](#fixed-issues-764)Fixed Issues This release contains the following fixes: #### [](#cluster-manager-4)Cluster Manager | Issue | Description | Resolution | | ------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------ | | [MB-62219](https://jira.issues.couchbase.com/browse/MB-62219) | The cluster manager was unable to rotate the root certificate when a new root uses the same private key as the old root. | Issue resolved. | | [MB-62413](https://jira.issues.couchbase.com/browse/MB-62413) | When a username is extracted from a client certificate, the candidate username is checked for its existence in couchbase-server. If such a user doesn't exist, the algorithm now doesn't stop but tries to extract another candidate username. | Issue resolved. | | [MB-63871](https://jira.issues.couchbase.com/browse/MB-63981) | The /prometheus\_sd\_config endpoint provides a new option clusterLabels which species the cluster name and cluster UUID be returned. Prometheus will use them as labels in time series data. | This provides a method to guarantee uniqueness for stats with the same name gathered from multiple clusters. | #### [](#storage-engine-3)Storage Engine | Issue | Description | Resolution | | ------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------ | | [MB-62678](https://jira.issues.couchbase.com/browse/MB-62678) | Resolved an issue where TTL-driven deletions via VBucket::deleteItem could generate invalid tombstones containing a document body. This issue occurred when TTL was triggered during the second phase of a 2-phase delete operation. | The fix ensures that when TTL triggers at CMD\_DEL, the document body is correctly removed and a valid tombstone is generated. | | [MB-63261](https://jira.issues.couchbase.com/browse/MB-63261) | An issue occurred caused by a race condition in the index recovery code path, which may result in item count mismatch and wrong query results.Prior to Release 7.6.0, this issue may occur during an Indexer restart. However, as part of the file-based rebalance process introduced in 7.6.0, a recovery of the index is performed after the index is moved, which increases the likelihood that the race condition might be reached. | The race condition has been addressed and the issue is resolved. | #### [](#xdcr-6)XDCR | Issue | Description | Resolution | | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [MB-62383](https://jira.issues.couchbase.com/browse/MB-62383) | In rare situations, a document with a very large CAS could be inserted into a bucket. It was possible for XDCR to replicate this document with malformed CAS to other clusters. | XDCR now has built-in guardrails to prevent documents with malformed CAS beyond a certain drift threshold from being replicated and then to notify the user if this situation occurs via UI and logs. | | [MB-62410](https://jira.issues.couchbase.com/browse/MB-62410) | Connection Pre-check did support all inputs normally accepted by XDCR | XDCR connection pre-check now supports alternate addresses, DNS SRV, and works identically to XDCR remote cluster references. | | [MB-63738](https://jira.issues.couchbase.com/browse/MB-63738) | The XDCR dashboard on Source cluster now shows a UI alert when a pipeline is stuck due to EACCESS errors while writing to Target cluster. | Issue resolved. | #### [](#query-service-9)Query Service | Issue | Description | Resolution | | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [MB-62932](https://jira.issues.couchbase.com/browse/MB-62932) | The execution of prepared statements containing (\*) expressions in the projection can return incorrect results in scenarios where the encoded plans of such statements need to be decoded before execution. | Issue resolved. | | [MB-63016](https://jira.issues.couchbase.com/browse/MB-63016) | If an index is defined with a CASE statement as an index key, and the CASE statement contains a not-equal expression, and the same CASE statement is used in the projection clause of a query, then the covering index scan is not performed properly. | The issue is fixed, and we now use covering index scan appropriately. | | [MB-63069](https://jira.issues.couchbase.com/browse/MB-63069) | In versions 7.6.2, and 7.6.3, queries with a FROM clause containing an UNNEST and ORDER BY with a LIMIT or LIMIT + OFFSET clauses, then in some cases incorrect results were observed when the ORDER could not be pushed down to the indexer. | Issue resolved. | | [MB-63414](https://jira.issues.couchbase.com/browse/MB-63414) | If memory\_quota is set to a value and Query uses a non-covered array index, it can result in Request has exceeded memory quota error. | Issue resolved. | | [MB-64155](https://jira.issues.couchbase.com/browse/MB-64155) | In previous versions of Couchbase Server, a clear delimiter between a numeric constant and a keyword was not required. | From version 7.6.4+, a statement containing text such as: … 1AND …will now correctly generate a syntax error indicating it is an invalid number.Correct such instances by inserting a space between the numeric constant and the following token, e.g. … 1 AND …. | | [MB-63518](https://jira.issues.couchbase.com/browse/MB-63518) | An API issue has been resolved where attempting to set the completed-stream-size to zero when it was already zero via the administrative REST API would: Prevent stream completion. Block access to the system:vitals keyspace or vitals end-point. Require a full Query process restart on affected nodes as the only previous workaround. | Issue resolved. | | [MB-63420](https://jira.issues.couchbase.com/browse/MB-63420) | A server panic was resolved when processing an aggregate function with a less-common reference structure, such as MAX(\[d.date, d\]\[1\]). The more standard form MAX(\[d.date, d\])\[1\] was not impacted. The fix ensures stable query processing for this edge case. | Issue resolved. | #### [](#eventing-service-2)Eventing Service | Issue | Description | Resolution | | ------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [MB-63014](https://jira.issues.couchbase.com/browse/MB-63014) | In earlier versions of Couchbase, during eventing function deployment or resumption, KV service disruptions (like network partitions) could leave LCB instances in an unrecoverable, unhealthy state. This caused the eventing function to become permanently stuck, with subsequent operations failing to return control, rendering the function non-functional. | This issue has been resolved. Couchbase Eventing now actively monitors LCB instance statuses and implements a "lazy" retry mechanism for bootstrapping unhealthy instances. The retry process continues until the operation times out, which is dynamically determined by the script timeout. This ensures that JavaScript code remains responsive, with mutations timing out gracefully if bootstrap attempts fail, instead of causing a complete function lockup. | #### [](#index-service-4)Index Service | Issue | Description | Resolution | | ------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [MB-61387](https://jira.issues.couchbase.com/browse/MB-61387) | To speed up the initial process of building the index, the index service has an optimization that skips checking for existing entries and directly adds new ones. This optimization is crucial for the initial build but should not be used for updates to existing indexes. Unfortunately, in a rare sequence of events, all indexes might be enabled for this optimization, leading to duplicate entries in the storage layer, leading to incorrect results. | The optimization is now only enabled for those indexes that are undergoing an initial build process. | | [MB-62220](https://issues.couchbase.com/browse/MB-62220) | We have an optimization in place which avoids unnecessary index movements when a swap rebalance is performed. A minor bug in this optimization interfered with rebuilding user-dropped replicas/lost replicas during such a rebalance where we didn't consider new nodes coming in when placing lost indexes. | Adds a sorted pseudo-random order where we give higher priority to new incoming nodes followed by old nodes staying in the cluster when we try to place lost indexes. Hence, we can repair lost replicas. | | [MB-62919](https://jira.issues.couchbase.com/browse/MB-62919) | After enabling GSI shard-based rebalance from the Web UI and saving the settings, it was not possible to disable the same setting by unticking the box. The box is greyed out and cannot be interacted with. | Issue resolved. | | [MB-63276](https://jira.issues.couchbase.com/browse/MB-63276) | An issue in the rebalancer caused several partitions to miss streaming mutations when partitioned indexes were moved during file-based rebalances. This issue resulted in corrupt indexes as not all data was processed.The issue occurred only with partitioned indexes with file-based rebalances enabled. | Issue resolved. | #### [](#search-service-4)Search Service | Issue | Description | Resolution | | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | [MB-62427](https://jira.issues.couchbase.com/browse/MB-62427) | In index definitions from version 6.x, the segmentVersion parameter is absent, with it previously defaulting to v11\. With 7.6 we've updated the default to v16\. So when the segmentVersion is absent, the v16 code will be going into effect. An issue in the v16 code while interpreting data with no vector fields caused an alignment panic. This panic is fixed with 7.6.4, allowing 6.x index definitions to work ok in 7.6.4. This problem occurs only for index definitions that survive an upgrade from 6.x to 7.x and then 7.6.x without being "re-built" meaning they'd still be using the v11 file format. Indexes that were introduced in server version 7.x and later or re-built after the cluster was fully upgraded to 7.x, (which will have a segmentVersion:15 setting within their index definition) will not encounter this issue, because they invoke the v15 code. | In summary, version 7.6.4 now supports upgrades of 6.x index definitions. However, Couchbase recommends upgrading indexes to 15+ segment version format for improvements in indexing footprint and performance.Issue resolved. | #### [](#backup-service)Backup Service | Issue | Description | Resolution | | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------- | | [MB-61013](https://jira.issues.couchbase.com/browse/MB-61013) | The Backup service incorrectly allowed backups to be created in the data directory because the server could delete the backup files. | The server will not allow archives to be created in the data directory. | ### [](#known-issues-764)Known Issues This release contains the following known issues: #### [](#query-service-10)Query Service | Issue | Description | Workaround | | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | [MB-64966](https://jira.issues.couchbase.com/browse/MB-64966) | Scope level user-defined functions (UDFs), sequences, and histogram data are stored in the bucket/\_system/\_query collection. FLUSHing the bucket will delete the scoped UDF entries. When the UDFs are executed, it will work until the UDFs are evicted from the cache. After that, the execution will always result in an error. Sequences metadata is also stored in the bucket/\_system/\_query collection. FLUSHing the bucket will delete the entries. When executed, sequences will return errors once evicted from the cache. FLUSHing the bucket will also delete statistics data stored in the bucket/\_system/\_query collection. By using stale statistics stored in the cache, a non-optimal plan could be generated. | For user-defined functions, you can do one of the following: Recreate the scoped user-defined functions after the FLUSH. Use global UDFs instead of scoped UDFs. (Global UDFs are not stored in the \_query collection.) Create scoped UDFs on the bucket that does not have FLUSH enabled and then reference them via a fully qualified name (bucket.scope.UDFname). For sequence metadata: After the FLUSH, recreate the sequence, or Create sequences on the bucket that does not have FLUSH enabled and then reference them via a fully qualified name (bucket.scope.UDFname). For statistical data, rerun UPDATE STATISTICS on all the indexes on every scope and collections in the bucket that was flushed. | ## [](#release-7-6-3-september-2024)Release 7.6.3 (September 2024) Couchbase Server 7.6.3 was released in September 2024\. This maintenance release contains new features and fixes several known issues. For detailed information on new features and enhancements, please see [What's New in Version 7.6](../introduction/whats-new.md). ### [](#deprecated-7-6-3)Deprecated Platforms The use of x86 processors that do not support Advanced Vector Extensions 2 (AVX2) is deprecated in version 7.6.3\. These instructions are available in most Intel processors produced since 2013 and AMD processors produced since 2015\. See [System Requirements](../install/pre-install.md#x86-processors) for details. ### [](#fixed-issues-763)Fixed Issues This release contains the following fixes: #### [](#cluster-manager-5)Cluster Manager | Issue | Description | Resolution | | ------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------- | | [MB-63070](https://jira.issues.couchbase.com/browse/MB-63070) | An issue occurred where cbcollect\_info did not process some … tags, especially when they were present at the end of the file or inside binary data. As a result, some logs that should have been redacted were not redacted. | Issue resolved. | #### [](#storage-engine-4)Storage Engine | Issue | Description | Resolution | | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | --------------- | | [MB-62984](https://jira.issues.couchbase.com/browse/MB-62984) | When a Couchbase Data Service experienced a hard failover or crashed with data loss, DCP clients (like those used with Elasticsearch and Kafka) sometimes received incomplete or partial snapshots of the data. This incomplete data sometimes leads to rare situations where the Data Service crashed repeatedly. | Issue resolved. | | [MB-63261](https://jira.issues.couchbase.com/browse/MB-63261) | An issue caused by a race condition in the index recovery code path sometimes resulted in an item count mismatch and wrong query results. Prior to Release 7.6.0, this issue sometimes occurred during Indexer restart. However, as part of the file-based rebalance process introduced in 7.6.0, a recovery of the index is performed after the index is moved, which increases the likelihood that this race condition might be reached. | Issue resolved. | #### [](#query-service-11)Query Service | Issue | Description | Resolution | | ------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------- | | [MB-63024](https://jira.issues.couchbase.com/browse/MB-63024) | A query sometimes returned the error: Nested aggregates not allowed under the following conditions: query contains in its FROM clause a subquery used as the inner of a join the subquery is used as an inner of a nested-loop join in query plan the subquery only accesses a single keyspace (i.e., no joins/nests/unnests) the subquery contains one or more aggregates (e.g., COUNT) in its projection the subquery contains a GROUP BY clause, and the GROUP BY list does not match index key order of any secondary indexes defined a secondary index exists that allows index group/aggregate pushdown for the subquery the cost-based optimizer is ON (which is the default), and a previous UPDATE STATISTICS/ANALYZE command has been run on the keyspace referenced in the subquery. | Issue resolved. | | [MB-63060](https://jira.issues.couchbase.com/browse/MB-63060) | An issue occurred when migrating nested UDFs to any 7.6.x release from a previous version. In cases when an inline UDF called another UDF, query nodes became unresponsive. | Issue resolved. | | [MB-63078](https://jira.issues.couchbase.com/browse/MB-63078) | When upgrading to a 7.6.x release, if buckets were loaded by Query nodes before they were fully migrated to 7.6.x format, Query continually reloaded the bucket on access, leading to degraded performance. This issue has been resolved in 7.6.3. | Issue resolved. | | [MB-63147](https://jira.issues.couchbase.com/browse/MB-63147) | An issue occurred with user-defined functions (UDFs) that contained queries defined with a common-table expression (CTE). If the CTE contained references to the UDF arguments, the execution of the UDF returned an error indicating "correlation reference is not allowed." | Issue resolved. | #### [](#index-service-5)Index Service | Issue | Description | Resolution | | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------- | | [MB-63193](https://jira.issues.couchbase.com/browse/MB-63193) | An issue in the rebalancer code caused several partitions to miss streaming mutations when partitioned indexes were moved during file-based rebalance. This issue resulted in corrupt indexes, as not all data will be processed. The issue occurred only with partitioned indexes when file-based rebalance was enabled. | Issue resolved. | #### [](#analytics-service-2)Analytics Service | Issue | Description | Resolution | | ------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------- | | [MB-62923](https://jira.issues.couchbase.com/browse/MB-62923) | An issue with the HTTP client lifecycle resulted in leaked TCP connections between the Analytics service processes during internal credentials rotation, eventually leading to ephemeral port exhaustion. | Issue resolved. | | [MB-62949](https://jira.issues.couchbase.com/browse/MB-62949) | When a query encounters a failure, the details of the exception can get masked by subsequent exceptions, leading to the loss of the root cause of the query failure. | Issue resolved. | ### [](#known-issues-763)Known Issues This release contains the following known issues: #### [](#query-service-12)Query Service | Issue | Description | Workaround | | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | [MB-63414](https://jira.issues.couchbase.com/browse/MB-63414) | If memory\_quota is set to a value and Query uses a non-covered array index, it can result in Request has exceeded memory quota error. | Disable memory quota or [contact support](https://www.couchbase.com/support/working-with-technical-support/) for alternatives. This issue is fixed on Capella. | | [MB-64966](https://jira.issues.couchbase.com/browse/MB-64966) | Scope level user-defined functions (UDFs), sequences, and histogram data are stored in the bucket/\_system/\_query collection. FLUSHing the bucket will delete the scoped UDF entries. When the UDFs are executed, it will work until the UDFs are evicted from the cache. After that, the execution will always result in an error. Sequences metadata is also stored in the bucket/\_system/\_query collection. FLUSHing the bucket will delete the entries. When executed, sequences will return errors once evicted from the cache. FLUSHing the bucket will also delete statistics data stored in the bucket/\_system/\_query collection. By using stale statistics stored in the cache, a non-optimal plan could be generated. | For user-defined functions, you can do one of the following: Recreate the scoped user-defined functions after the FLUSH. Use global UDFs instead of scoped UDFs. (Global UDFs are not stored in the \_query collection.) Create scoped UDFs on the bucket that does not have FLUSH enabled and then reference them via a fully qualified name (bucket.scope.UDFname). For sequence metadata: After the FLUSH, recreate the sequence, or Create sequences on the bucket that does not have FLUSH enabled and then reference them via a fully qualified name (bucket.scope.UDFname). For statistical data, rerun UPDATE STATISTICS on all the indexes on every scope and collections in the bucket that was flushed. | #### [](#index-service-6)Index Service | Issue | Description | Workaround | | -------------------------------------------------------- | ------------------------------------------------------ | ----------------------------------- | | [MB-62220](https://issues.couchbase.com/browse/MB-62220) | Dropped replicas are not rebuilt during swap rebalance | Drop and then recreate the indexes. | ## [](#release-7-6-2-july-2024)Release 7.6.2 (July 2024) Couchbase Server 7.6.2 was released in July 2024\. This maintenance release contains new features and fixes several known issues. For detailed information on new features and enhancements, please see [What's New in Version 7.6](../introduction/whats-new.md). ### [](#fixed-issues-762)Fixed Issues This release contains the following fixes: #### [](#cluster-manager-6)Cluster Manager | Issue | Description | Resolution | | -------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [MB-60621](https://issues.couchbase.com/browse/MB-60621) | The sys\_cpu\_cgroup\_seconds\_total{mode="usage"} stat also included the amount of time for sys\_cpu\_cgroup\_seconds\_total{mode="user"} and sys\_cpu\_cgroup\_seconds\_total{mode="sys"}. As a result, using certain functions e.g. sum(sys\_cgroup\_seconds\_total) would double the user count and sys time. | To prevent this, the sys\_cpu\_cgroup\_seconds\_total{mode="usage"} is no longer returned and is replaced with sys\_cpu\_cgroup\_usage\_seconds\_total. | | [MB-60883](https://issues.couchbase.com/browse/MB-60883) | The Cache Miss Ratio metric showed the number of background fetch operations over the total number of read operations. However, the implementation meant that: the value did not represent a meaningful quantity to the user in all configurations. the meaning of the value changed between different bucket types and eviction policies. The value could also show as being greater than 100%, as it did not account for all cases of background fetch. | The metric now shows the ratio between the number of read operations which failed due to the key not being present, and all read operations: kv\_ops{op="get", result="miss"} / kv\_ops{op="get"}. | #### [](#storage-engine-5)Storage Engine | Issue | Description | Resolution | | -------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [MB-60879](https://issues.couchbase.com/browse/MB-60879) | HashTable resizing can be avoided by setting the minimum size to be large enough, but there was no metric to indicate what that should be. | Added kv\_vb\_ht\_avg\_size and kv\_vb\_ht\_max\_size which summarizes the current HT sizes across vBuckets. | | [MB-61525](https://issues.couchbase.com/browse/MB-61525) | With the removal of the dedicated DCP consumer buffer in 7.6.0 in a temporary out-of-memory scenario, a consumer node could continue to consume DCP mutations and add to the checkpoint beyond the allocated checkpoint memory quota. This is limited by the dcp consumer buffer quota. | A new metric has been added to track the sum of the checkpoint quota and the DCP consumer buffer quota. This is used to make sure the memcached memory allocation on a consumer node isn't exceeding the allocated memory quotas: checkpoint\_mem-usage limit = checkpoint\_memory\_ratio \+ dcp\_consumer\_buffer\_ratio. | | [MB-62547](https://issues.couchbase.com/browse/MB-62547) | A critical issue occurs when performing an off-line-upgrade, graceful failover, or delta-recovery upgrade methods on index service nodes from Couchbase Server versions 7.1 through 7.2 to versions 7.6.0 or 7.6.1\. The upgrade corrupted existing indexes requiring you to drop and rebuild them. | Issue resolved. | #### [](#query-service-13)Query Service | Issue | Description | Resolution | | -------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------- | | [MB-61014](https://issues.couchbase.com/browse/MB-61014) | The planner may not pick a covering index if the index is defined with a complex WHERE clause (e.g. AND or OR clauses involving !=, NOT or IN predicates). | Issue resolved. | | [MB-61171](https://issues.couchbase.com/browse/MB-61171) | In rare circumstances with high-load Query, requests can fail to complete, blocking rebalance attempts.Such requests don't affect other regular processing beyond occupying a servicer, but a rebalance can't complete until they do. By the time it is an issue, it is likely that the client that submitted such a request has already terminated, and the request is just stuck in Query processing. Deleting such a request from system:active\_requests using the REST API may release it.Forcibly restarting the Query service will clear the issue. | Issue resolved. | | [MB-61564](https://issues.couchbase.com/browse/MB-61564) | Incorrect return code when attempting to create an index that already exists. The system returns the error: 200: index already exists. | Issue resolved: the system will now return: 409: index already exists. | | [MB-61764](https://issues.couchbase.com/browse/MB-61764) | In rare cases, Couchbase Server could report an IndexOutOfBoundsException error if a SQL++ query contained a subquery with an IN clause. | Issue resolved. | #### [](#eventing-service-3)Eventing Service | Issue | Description | Resolution | | -------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------- | | [MB-61488](https://issues.couchbase.com/browse/MB-61488) | When performing a Sub-Document operation using the Eventing couchbase.mutateIn Sub-Document API, the operation sometimes caused exceptions in the JavaScript code and failed with the error code LCB\_ERR\_SUBDOC\_XATTR\_UNKNOWN\_MACRO. | Issue resolved. | | [MB-50944](https://issues.couchbase.com/browse/MB-50944) | Eventing did not properly support read-write bindings to collections with Sync Gateway attached at the source. Adding a new Eventing function failed if the bucket alias was set to read-write. | Issue resolved. | #### [](#index-service-7)Index Service | Issue | Description | Resolution | | -------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------- | | [MB-61387](https://issues.couchbase.com/browse/MB-61387) | To speed up the initial process of building the index, the index service has an optimization that skips checking for existing entries and directly adds new ones. This optimization is crucial for the initial build but should not be used for updates to existing indexes. Unfortunately, in a rare sequence of events, all indexes might be accidentally enabled for this optimization, leading to duplicate entries in the storage layer and causing incorrect results. | Optimization is only enabled for those indexes that are undergoing the initial build process. | | [MB-61793](https://issues.couchbase.com/browse/MB-61793) | The indexes made using the plasma storage engine have both in-memory and on-disk components. There are some components which are always present in memory and are never evicted to disk, so they consume the same memory even at varying resident ratios.For any rebalance or index planning calculation, the memory usage of all indexes at the recommended resident ratio is estimated and used. During these estimations, the memory taken by the fixed in-memory component was also scaled up with the respective resident ratio, which caused overestimation. This overestimation is only evident at very low resident ratios and could sometimes cause rebalance failure. | Now, a more accurate calculation is made to avoid overestimating the memory of the indexes. | | [MB-62199](https://issues.couchbase.com/browse/MB-62199) | During restore, the index planning operation adds replicas for lost replicas of indexes in the plan. If multiple indexes exist with the same name, there are lost replicas, and there are not enough indexer nodes to hold all the index replicas in the plan, then extra replicas will not be removed from the plan, and can remain on the old node.This causes restore operation failures. | Issue resolved. | #### [](#search-service-5)Search Service | Issue | Description | Resolution | | -------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------- | | [MB-60719](https://issues.couchbase.com/browse/MB-60719) | Running a query with score:none results in response containing score:0. The score is incorrectly added to the response. | If a user runs a query with score:none then the query response will no longer contain score:0. | | [MB-61043](https://issues.couchbase.com/browse/MB-61043) | In scenarios where a rebalance is followed by a failover, the partitions are not evenly distributed across all nodes, causing a skewness. | Skewness has been resolved. | | [MB-61310](https://issues.couchbase.com/browse/MB-61310) | During rebalance, when moving partitions around, we track the progress of movement and then check the seq numbers the partition has caught up relative to the view of the partition on source node and also the KV's view.This progress monitoring procedure was only for active partitions | You can now optionally monitor the replicas as well | | [MB-61654](https://issues.couchbase.com/browse/MB-61654) | Prometheus fails to scrape the new xattrs fields) | Problem caused by the use of \*num\_vectors which uses Prometheus-reserved character; num\_vectors will no longer show up in the stats. | #### [](#tools-3)Tools | Issue | Description | Resolution | | -------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------ | | [MB-60630](https://issues.couchbase.com/browse/MB-60630) | Moving a cloud backup archive in a normal GCP bucket to a locked GCP bucket (which allows creating new files but prohibits modifying or deleting pre-existing objects) and then performing a restore from that bucket.The restore didn't fail, which would be the expected behavior; instead, the restore hangs. The problem occurs because cbbackupmgr always retries on 403s responses when using a GCP client, since it considered them intermittent. | cbbackupmgr no longer considers 403s as temporary errors, and will not always retry when receiving them. | | [MB-61630](https://issues.couchbase.com/browse/MB-61630) | Previously it was not possible to import an encrypted backup repository into the backup service as we did not accept the KMS parameters. | Both the UI and REST API now allow users to specify the KMS and its authentication parameters so an encrypted repository can successfully be imported. | | [MB-61631](https://issues.couchbase.com/browse/MB-61631) | Previously, passing a relative path to cbbackupmgr as \--obj-staging-dir, the backup or restore would fail with an empty object name. | Issue resolved. | ### [](#known-issues-762)Known Issues This release contains the following known issues: #### [](#query-service-14)Query Service | Issue | Description | Workaround | | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | [MB-63414](https://jira.issues.couchbase.com/browse/MB-63414) | If memory\_quota is set to a value and Query uses a non-covered array index, it can result in Request has exceeded memory quota error. | Disable memory quota or [contact support](https://www.couchbase.com/support/working-with-technical-support/) for alternatives. | | [MB-64966](https://jira.issues.couchbase.com/browse/MB-64966) | Scope level user-defined functions (UDFs), sequences, and histogram data are stored in the bucket/\_system/\_query collection. FLUSHing the bucket will delete the scoped UDF entries. When the UDFs are executed, it will work until the UDFs are evicted from the cache. After that, the execution will always result in an error. Sequences metadata is also stored in the bucket/\_system/\_query collection. FLUSHing the bucket will delete the entries. When executed, sequences will return errors once evicted from the cache. FLUSHing the bucket will also delete statistics data stored in the bucket/\_system/\_query collection. By using stale statistics stored in the cache, a non-optimal plan could be generated. | For user-defined functions, you can do one of the following: Recreate the scoped user-defined functions after the FLUSH. Use global UDFs instead of scoped UDFs. (Global UDFs are not stored in the \_query collection.) Create scoped UDFs on the bucket that does not have FLUSH enabled and then reference them via a fully qualified name (bucket.scope.UDFname). For sequence metadata: After the FLUSH, recreate the sequence, or Create sequences on the bucket that does not have FLUSH enabled and then reference them via a fully qualified name (bucket.scope.UDFname). For statistical data, rerun UPDATE STATISTICS on all the indexes on every scope and collections in the bucket that was flushed. | #### [](#index-service-8)Index Service | Issue | Description | Workaround | | -------------------------------------------------------- | ------------------------------------------------------ | ----------------------------------- | | [MB-62220](https://issues.couchbase.com/browse/MB-62220) | Dropped replicas are not rebuilt during swap rebalance | Drop and then recreate the indexes. | ## [](#release-7-6-1-april-2024)Release 7.6.1 (April 2024) Couchbase Server 7.6.1 was released in April 2024\. This maintenance release fixes several known issues. For detailed information on new features and enhancements, please see [What's New in Version 7.6](../introduction/whats-new.md). ### [](#fixed-issues-761)Fixed Issues This release contains the following fixes: #### [](#storage-engine-6)Storage Engine | Issue | Description | Resolution | | -------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------- | --------------- | | [MB-61154](https://issues.couchbase.com/browse/MB-61154) | When bucket data exceeded 4 TB and Magma was used as the storage engine, rebalance sometimes hung and failed to run to completion. | Issue resolved. | ### [](#known-issues-761)Known Issues This release contains the following known issue: #### [](#storage-engine-7)Storage Engine | Issue | Description | Workaround | | -------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------- | | [MB-61076](https://issues.couchbase.com/browse/MB-61076) | Scheduled merges – that is merges which are done due to a task in a plan – will always fail.The system will not perform the merge, and it will leave the backups that should have been merged in place, ensuring no data is lost. | You can perform manual merges through the UI, or using the API. | #### [](#index-service-9)Index Service | Issue | Description | Workaround | | -------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | [MB-62547](https://issues.couchbase.com/browse/MB-62547) | A critical issue occurs when using the offline-upgrade or graceful failover/delta-recovery upgrade methods on Index Service nodes from Couchbase Server versions 7.1 through 7.2 to versions 7.6.0 or 7.6.1. Using these methods to upgrade Index Service nodes to these versions corrupts existing indexes that require you to drop and rebuild them. | If you have one or more Index Service nodes, Couchbase suggests you delay upgrading until the release of the next service patch for Couchbase Server (7.6.2) which resolves this issue. To work around this issue, use the [Swap Rebalance method](../install/upgrade-procedure-selection.md#swap-rebalance) when upgrading to Couchbase Server 7.6.x. | #### [](#query-service-15)Query Service | Issue | Description | Workaround | | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | [MB-64966](https://jira.issues.couchbase.com/browse/MB-64966) | Scope level user-defined functions (UDFs), sequences, and histogram data are stored in the bucket/\_system/\_query collection. FLUSHing the bucket will delete the scoped UDF entries. When the UDFs are executed, it will work until the UDFs are evicted from the cache. After that, the execution will always result in an error. Sequences metadata is also stored in the bucket/\_system/\_query collection. FLUSHing the bucket will delete the entries. When executed, sequences will return errors once evicted from the cache. FLUSHing the bucket will also delete statistics data stored in the bucket/\_system/\_query collection. By using stale statistics stored in the cache, a non-optimal plan could be generated. | For user-defined functions, you can do one of the following: Recreate the scoped user-defined functions after the FLUSH. Use global UDFs instead of scoped UDFs. (Global UDFs are not stored in the \_query collection.) Create scoped UDFs on the bucket that does not have FLUSH enabled and then reference them via a fully qualified name (bucket.scope.UDFname). For sequence metadata: After the FLUSH, recreate the sequence, or Create sequences on the bucket that does not have FLUSH enabled and then reference them via a fully qualified name (bucket.scope.UDFname). For statistical data, rerun UPDATE STATISTICS on all the indexes on every scope and collections in the bucket that was flushed. | #### [](#search-service-6)Search Service | Issue | Description | Workaround | | -------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ---------------------------------------------- | | [MB-60719](https://issues.couchbase.com/browse/MB-60719) | Older SDKs might have failed operations when you access the Search Service with the disableScoring option set to false. This is a breaking change due to a change in the response payload. | Set the disableScoring option in SDKs to true. | ## [](#release-7-6-0-march-2024)Release 7.6.0 (March 2024) ### [](#new-features-760)New Features and Enhancements For detailed information on new features and enhancements, please see [What's New in Version 7.6](../introduction/whats-new.md). ### [](#deprecated-features-and-platforms-760)Deprecated and Removed Features and Platforms * The following platforms are still supported, but deprecated in Couchbase Server 7.6: * Amazon Linux 2 LTS x86 & ARM * Microsoft Windows Server 2019 * Ubuntu 20.04 LTS x86 & ARM * SUSE Linux Enterprise Server Version 12 * MacOS 12 (Monterey) x86 & ARM * We are removing these platforms from support (they are already deprecated): * CentOS 7.x * Debian Linux 10 (Buster) * MacOS 11 (BigSur) * Red Hat Enterprise Linux (RHEL) 7.x * Removed support for TLS `1.0` and `1.1`. Both the standards bodies and Couchbase have already deprecated these versions due to their lack of security. ([MB-58045](https://issues.couchbase.com/browse/MB-58045)) * The `cbbackup` and `cbrestore` utilities have been removed from Couchbase Server 7.6\. The same functionality is provided in `cbbackupmgr`. * [Removed support for password-less buckets](#passwordless-deprecated). * Customers using the Couchbase `yum` or `apt` repositories to install Couchbase Server on Linux must ensure they are using the latest version `1.0-13` of the couchbase-release meta-package prior to upgrading to Couchbase Server 7.6.0 or later. To check which version you currently have installed: * On RPM-based systems: `rpm -q couchbase-release` (should return `couchbase-release-1.0-13.noarch`) * On Debian-based systems: `dpkg -s couchbase-release|grep Version` (should return `Version: 1.0-13`) If you have a version lower than `1.0-13` installed, please follow the instructions for [Installing Couchbase Server on Red Hat](../install/rhel-suse-install-intro.md#install-using-yum)or [ Installing Couchbase Server on Ubuntu and Debian](../install/ubuntu-debian-install.md#install-using-apt) to install the latest couchbase-release meta-package. ### [](#fixed-issues-760)Fixed Issues This release contains the following fixes. #### [](#cluster-manager-7)Cluster Manager | Issue | Description | Resolution | | -------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [MB-60568](https://issues.couchbase.com/browse/MB-60568) | CPU utilization rate may be incorrect in a VM.When running a VM on a XEN hypervisor, stats were computed using the number of processors configured for the entire system. | Stats now use the number of logical processors online on the system. This correction affects the following stats: sys\_cpu\_host\_cores\_available sys\_cpu\_utilization\_rate sys\_cpu\_host\_utilization\_rate | #### [](#data-service-5)Data Service | Issue | Description | Resolution | | -------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------- | | [MB-58088](https://issues.couchbase.com/browse/MB-58088) | When the client sends an unlock request for a document that is not locked, the server returns a "temp fail" error code. This causes the client to retry until the operation times out. | The server returns a new "not locked" error code. | | [MB-59060](https://issues.couchbase.com/browse/MB-59060) | When the client sends an unlock request for a document that is not cached in Full Eviction mode, the server returns a "temp fail" error code, even if the document is stored on disk. This causes the client to retry until the operation times out. | The metadata of locked documents are kept in the hashtable. The server returns a new "not locked" error code if the document exists, "not found" otherwise. | #### [](#xdcr-7)XDCR | Issue | Description | Resolution | | -------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [MB-58671](https://issues.couchbase.com/browse/MB-58671) | Erroneous network conditions could lead to checkpoint manager slow at stopping. | Ensure the checkpoint manager stops, even if it has trouble starting due to network issues. | | [MB-59233](https://issues.couchbase.com/browse/MB-59233) | In low-priority replications, it is possible for a Data Service stream to end temporarily and for XDCR to not handle it correctly. This will lead to a hung replication. | Now, XDCR restarts the pipeline if a data service stream ends.This ensures replication continues. | | [MB-59320](https://issues.couchbase.com/browse/MB-59320) | Race condition in starting and stopping XDCR source nozzle could lead to a memory leak | Fixed the race condition | | [MB-59416](https://issues.couchbase.com/browse/MB-59416) | If the Bandwidth throttler is used, race condition may occur during pipeline shutdown where the Out nozzle is unable to exit | Fix race condition during shutdown to ensure out nozzle closes properly. | | [MB-59499](https://issues.couchbase.com/browse/MB-59499) | In a slow running backfill replication, XDCR could be too aggressive in restarting pipelines. | Ensure XDCR does not restart backfill pipelines if some progress is observed periodically. | | [MB-59669](https://issues.couchbase.com/browse/MB-59669) | If a replication is idle without mutations, XDCR is unable to detect that a target bucket failover occurred. | Ensure target-side failover detection takes place, even if the source has no incoming mutations | | [MB-59745](https://issues.couchbase.com/browse/MB-59745) | When a target document is locked, and a non-optimistic LWW replication is taking place, XDCR will retrieve a "locked CAS" of maxUint. This will cause the source mutation to lose, and lead to scenarios where the mutation is not replicated, even if it should have won conflict resolution. | XDCR will retry conflict resolution for the duration that the document is locked in pessimistic replication. This will ensure that a valid CAS is used for source-side conflict resolution. | #### [](#query-service-16)Query Service | Issue | Description | Resolution | | -------------------------------------------------------- | ------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------ | | [MB-39484](https://issues.couchbase.com/browse/MB-39484) | SQL++ will not support operations on legacy buckets without password specification. | Users must authenticate first to connect to the query service and execute any SQL statement. | | [MB-58648](https://issues.couchbase.com/browse/MB-58648) | Observed a memory leak with multiple executions of the same UDF function. | Fix the condition whereby UDF functions are being re-loaded into cache from storage every time the function is executed. | | [MB-59501](https://issues.couchbase.com/browse/MB-59501) | The system catalog allows users to see items without RBAC authentication or authorization. | Valid RBAC permissions are required to query the system catalog, and to view items stored in the catalog. | #### [](#index-service-10)Index Service | Issue | Description | Resolution | | -------------------------------------------------------- | ----------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------- | | [MB-59138](https://issues.couchbase.com/browse/MB-59138) | The system did not support nested flattened array indexes when an entry was missing in nested arrays. | The system now correctly expands null or missing entries for nested arrays. | #### [](#search-service-7)Search Service | Issue | Description | Resolution | | -------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [MB-57657](https://issues.couchbase.com/browse/MB-57657) | When running non-analytic queries from SQL++ there was an expectation to use the keyword analyzer. If the user specified any other analyzer, then the analyzer expectation was not met, leading to the error: No index available on keyspace. The non-analytical queries are: TermQuery PhraseQuery MultiPhraseQuery FuzzyQuery PrefixQuery RegexpQuery WildcardQuery | This restriction has been lifted in 7.6.0.The user will now be able to run queries via SQL++ without having to run the keyword analyzer. | | [MB-59858](https://issues.couchbase.com/browse/MB-59858) | When a Search index name is too long, the index silently fails to ingest documents. | The UI will now flag instances where the chosen index name is too long. | | [MB-60718](https://issues.couchbase.com/browse/MB-60718) | Index alias queries not returning cumulative (duplicate) results from its targets. | The fix prevents cyclic lockups within aliased index targets (aliases with the same targets pointing to each other to an infinite depth).The service also de-duplicates index targets. | #### [](#tools-4)Tools | Issue | Description | Resolution | | -------------------------------------------------------- | ------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------- | | [MB-57988](https://issues.couchbase.com/browse/MB-57988) | cli should allow modifying existing collection's maxTTL | The Couchbase CLI has been extended to allow the maxTTL (maximum time-to-live) to be modified for a collection. | ### [](#known-issues-760)Known Issues This release contains the following known issues: #### [](#net-sdk-compatibility).NET SDK Compatibility | Issue | Description | Workaround | | ---------------------------------------------------------- | ------------------------------------------------------------------------------------------------ | --------------------------------------------------------------------- | | [NCBC-3724](https://issues.couchbase.com/browse/NCBC-3724) | Versions of the .NET SDK earlier than 3.5.1 have compatibility issues with Couchbase Server 7.6. | Use version 3.5.1 or later of the .NET SDK with Couchbase Server 7.6. | #### [](#user-interface)User Interface | Issue | Description | Workaround | | -------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------- | | [MB-59352](https://issues.couchbase.com/browse/MB-59352) | When the Load Metadata from File option is selected, the Couchbase Server UI does not disable two options that can't be used: Validate metadata using trusted fingerprints and Verify Remote Peer. These two options are irrelevant during metadata upload. Selecting them will have no impact on the process. | NA | #### [](#failover)Failover | Issue | Description | Workaround | | -------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------- | | [MB-60062](https://issues.couchbase.com/browse/MB-60062) | When the auto-failover timeout setting is set to fewer than 5 seconds (the recommended minimum), you can no longer modify any cluster settings using the Couchbase Server UI. | Modify settings using the Nodes and Clusters REST API. For more information on the auto-failover settings, see the documentation. | #### [](#tools-5)Tools | Issue | Description | Workaround | | -------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------- | | [MB-61076](https://issues.couchbase.com/browse/MB-61076) | Scheduled merges (i.e. merges that are performed in a task in a plan) do not run. Note that backups scheduled for the merge are left in place so no data is lost. | Merge backups manually using the UI or using the API. | #### [](#storage-engine-8)Storage Engine | Issue | Description | Workaround | | -------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------- | | [MB-61154](https://issues.couchbase.com/browse/MB-61154) | In situations where bucket data exceeds 4 TB and Magma is being used as the storage engine, it is possible for rebalance to hang and fail to run to completion. | NA | #### [](#index-service-11)Index Service | Issue | Description | Workaround | | -------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | [MB-62547](https://issues.couchbase.com/browse/MB-62547) | A critical issue occurs when using the offline-upgrade or graceful failover/delta-recovery upgrade methods on Index Service nodes from Couchbase Server versions 7.1 through 7.2 to versions 7.6.0 or 7.6.1. Using these methods to upgrade Index Service nodes to these versions corrupts existing indexes that require you to drop and rebuild them. | If you have one or more Index Service nodes, Couchbase suggests you delay upgrading until the release of the next service patch for Couchbase Server (7.6.2) which resolves this issue. To work around this issue, use the [Swap Rebalance method](../install/upgrade-procedure-selection.md#swap-rebalance) when upgrading to Couchbase Server 7.6.x. | #### [](#query-service-17)Query Service | Issue | Description | Workaround | | ------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | [MB-64966](https://jira.issues.couchbase.com/browse/MB-64966) | Scope level user-defined functions (UDFs), sequences, and histogram data are stored in the bucket/\_system/\_query collection. FLUSHing the bucket will delete the scoped UDF entries. When the UDFs are executed, it will work until the UDFs are evicted from the cache. After that, the execution will always result in an error. Sequences metadata is also stored in the bucket/\_system/\_query collection. FLUSHing the bucket will delete the entries. When executed, sequences will return errors once evicted from the cache. FLUSHing the bucket will also delete statistics data stored in the bucket/\_system/\_query collection. By using stale statistics stored in the cache, a non-optimal plan could be generated. | For user-defined functions, you can do one of the following: Recreate the scoped user-defined functions after the FLUSH. Use global UDFs instead of scoped UDFs. (Global UDFs are not stored in the \_query collection.) Create scoped UDFs on the bucket that does not have FLUSH enabled and then reference them via a fully qualified name (bucket.scope.UDFname). For sequence metadata: After the FLUSH, recreate the sequence, or Create sequences on the bucket that does not have FLUSH enabled and then reference them via a fully qualified name (bucket.scope.UDFname). For statistical data, rerun UPDATE STATISTICS on all the indexes on every scope and collections in the bucket that was flushed. | #### [](#search-service-8)Search Service | Issue | Description | Workaround | | -------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ---------------------------------------------- | | [MB-60719](https://issues.couchbase.com/browse/MB-60719) | Older SDKs might have failed operations when you access the Search Service with the disableScoring option set to false. This is a breaking change due to a change in the response payload. | Set the disableScoring option in SDKs to true. | ## [](#documentation-for-earlier-versions)Documentation for Earlier Versions Documentation for earlier versions of Couchbase software can be found in the [Documentation Archive](https://docs-archive.couchbase.com/home/index.html).