---
title: Size Limits
description: Couchbase Server specifies size-limits, which affect server usage
  and implementation.
pubDate: 2026-08-17T09:53:44.266Z
antora:
  editUrl: https://github.com/couchbase/docs-server/edit/release/8.0/modules/learn/pages/clusters-and-availability/size-limitations.adoc
  xref: xref:server:learn:clusters-and-availability/size-limitations.adoc[]
---

[Consult the llms.txt file for a full list of contents](/llms.txt)
[View original HTML](/server/current/learn/clusters-and-availability/size-limitations.html)

# Size Limits

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

## [](#table-of-size-limits)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                       | 30                        | 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          | 60,000                    | 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.\[[1](#%5Ffootnotedef%5F1 "View footnote.")\]                                                                                                                                         |
| 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](../data/data.md#sub-documents-overview) operation.                                                                                                                                                                                                                                                 |
| Sub-document path nesting level               | 32                        | The maximum number of _levels_ a path may reference in a [sub-document](../data/data.md#sub-documents-overview) operation.                                                                                                                                                                                                                                                        |
| Maximum memcached and system-user connections | Administrator-defined     | 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](../../rest-api/rest-manage-cluster-connections.md), 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.                                                                                                                                                                                                                               |

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[1](#%5Ffootnoteref%5F1). Note that in practice a small number of the connections will be used by Couchbase for interprocess communications.