Size Limits

      Couchbase Server specifies size-limits, which affect server usage and implementation.

      Table of Size Limits

      The following limits are imposed by Couchbase Server.

      Limit Default Value Description

      Max key length

      250 bytes

      The maximum length of the document ID (key).

      Max value size

      20 MB

      The maximum size of the document, typically in JSON format.

      Max UI-editable document size

      10 MB

      The maximum supported size of a document that can be edited by means of the Couchbase Web Console UI. String-values whose size is greater than 486 KB are not displayed.

      Max buckets per cluster


      The maximum number of buckets in a cluster.

      Max view key size

      4096 bytes

      The maximum size of the key (first attribute) in the emit() function.

      Max doc size for indexing

      20 MB

      The maximum size of a document that can be indexed. The default value is set to 20 MB to ensure that all documents get indexed.

      In Couchbase Server version 2.x and earlier, the view engine enforced a limit of 1MB on documents that can be indexed. As a result, when the size of a document exceeded the limit, the view engine (in version 2.x) did not index that document.

      Max key-value size per document

      1 MB

      The maximum byte size allowed to be emitted for a single document and per view. This value is the sum of the sizes of all emitted keys and values.

      If a document emits a key-value pair that exceeds the specified maximum key-value size per document, an error is logged and that document is not indexed.

      Max concurrent key-value connections


      Each Couchbase Data node allows, by default, up to 60,000 concurrent key-value connections in total to the two client ports — 11207 (SSL) and 11210 (plain)-- over either one or both ports.[1]

      Function timeout

      1000 ms

      The maximum duration (in milliseconds) to execute all the MapReduce functions in a design document against a single document (map function) or against a list of map values or reductions (reduce or rereduce function). If the execution time for a document exceeds the specified value, the execution is aborted and that document is not indexed.

      Sub-document path length

      1024 bytes

      The maximum length of a sub-document path that may be used in a sub-document operation.

      Sub-document path nesting level


      The maximum number of levels a path may reference in a sub-document operation.

      Maximum memcached and system-user connections


      The maximum permitted numbers of connections permitted for memcached connections, and for system-user connections, for the cluster. These numbers are established by means of the REST API: see Managing Cluster Connections, for information.

      64-bit integers

      \(+-1 * (2^{63} - 1)\)

      Values outside this range are handled as 64-bit floating-point values, and are subject to approximation inherent in the IEEE floating-point format.

      1. Note that in practice a small number of the connections will be used by Couchbase for interprocess communications.