---
title: Modify Index Batch Size
description: Couchbase Server breaks the rebuilding of indexes during a
  rebalance into batches to limit the performance impact. You can use the REST
  API to change the size of these batches.
pubDate: 2026-08-17T09:53:44.266Z
antora:
  editUrl: https://github.com/couchbase/docs-server/edit/release/7.6/modules/rest-api/pages/rest-modify-index-batch-size.adoc
  xref: xref:7.6@server:rest-api:rest-modify-index-batch-size.adoc[]
---

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# Modify Index Batch Size

> Couchbase Server breaks the rebuilding of indexes during a rebalance into batches to limit the performance impact. You can use the REST API to change the size of these batches. 

> [!NOTE]
> Shard Based Rebalance and Rebalance Based on File Transfer are synonyms for File-based Rebalance.

## [](#http-method-and-uri)HTTP Method and URI

POST /settings

## [](#description)Description

Sets the _batch size_ Couchbase Server uses when rebuilding index files during rebalance. This setting has no effect on file-based rebalance. This setting controls the maximum number of indexes that a rebalance rebuilds concurrently. You must have either Full Admin or the Cluster Admin role to set this value.

## [](#curl-syntax)Curl Syntax

curl -X POST http://<node-ip-address-or-domain-name>:<port-number>/settings
  -u <username>:<password>
  -d '{"indexer.rebalance.transferBatchSize":<integer>}'

The port number must be either `9102` or `19102`, which are those of the `indexer_http_port` and `indexer_https_port` respectively. The `integer` should be a small integer that corresponds to the batch size to be established. The default is `3`.

The change automatically propagates to all Index-Service nodes, and will be remembered across node and cluster restarts.

## [](#responses)Responses

Success returns `200 OK`. Failure to authenticate returns `401 Unauthorized`. An incorrectly specified URI returns `404 Object Not Found`.

Failure correctly to specify the key `"indexer.rebalance.transferBatchSize"` generates no error, and returns `200 OK`.

## [](#example)Example

The following call establishes the batch size as `7`:

curl -v -X POST http://localhost:9102/settings -u Administrator:password \
-d '{"indexer.rebalance.transferBatchSize":7}'

If successful, the call returns `200 OK` and no object.

## [](#see-also)See Also

An overview of rebalance as it affects the Index Service, including an overview of _smart batching_, is provided in [Index Rebalance](../learn/clusters-and-availability/rebalance-and-index-service.md). For information on Couchbase-Server ports, see [Couchbase Server Ports](../install/install-ports.md).