# Configuration parameters
```json metadata
{
"schema_version": 2,
"title": "Configuration parameters",
"description": "Redis Search can be tuned through multiple configuration parameters. Some of these parameters can only be set at load-time, while other parameters can be set either at load-time or at run-time.",
"categories": ["docs","develop","stack","oss","rs","rc","oss","kubernetes","clients"],
"tableOfContents": {"sections":[{"children":[{"id":"search-bg-index-sleep-gap","title":"search-bg-index-sleep-gap"},{"id":"search-bg-index-sleep-duration-us","title":"search-bg-index-sleep-duration-us"},{"id":"search-conn-per-shard","title":"search-conn-per-shard"},{"id":"search-cursor-max-idle","title":"search-cursor-max-idle"},{"id":"search-cursor-reply-threshold","title":"search-cursor-reply-threshold"},{"id":"search-default-dialect","title":"search-default-dialect"},{"id":"search-ext-load","title":"search-ext-load"},{"id":"search-fork-gc-clean-numeric-empty-nodes","title":"search-fork-gc-clean-numeric-empty-nodes"},{"id":"search-fork-gc-clean-threshold","title":"search-fork-gc-clean-threshold"},{"id":"search-fork-gc-retry-interval","title":"search-fork-gc-retry-interval"},{"id":"search-fork-gc-run-interval","title":"search-fork-gc-run-interval"},{"id":"search-fork-gc-sleep-before-exit","title":"search-fork-gc-sleep-before-exit"},{"id":"search-friso-ini","title":"search-friso-ini"},{"id":"gc_policy","title":"GC_POLICY"},{"id":"search-gc-scan-size","title":"search-gc-scan-size"},{"id":"search-index-cursor-limit","title":"search-index-cursor-limit"},{"id":"search-max-aggregate-results","title":"search-max-aggregate-results"},{"id":"search-max-doctablesize","title":"search-max-doctablesize"},{"id":"search-max-expansions","title":"search-max-expansions"},{"id":"search-max-prefix-expansions","title":"search-max-prefix-expansions"},{"id":"search-max-search-results","title":"search-max-search-results"},{"id":"search-_max-foreground-timeout-limit","title":"search-_max-foreground-timeout-limit"},{"id":"search-min-operation-workers","title":"search-min-operation-workers"},{"id":"search-min-phonetic-term-len","title":"search-min-phonetic-term-len"},{"id":"search-min-prefix","title":"search-min-prefix"},{"id":"search-min-stem-len","title":"search-min-stem-len"},{"id":"search-multi-text-slop","title":"search-multi-text-slop"},{"id":"search-no-mem-pools","title":"search-no-mem-pools"},{"id":"search-no-gc","title":"search-no-gc"},{"id":"search-on-timeout","title":"search-on-timeout"},{"id":"search-partial-indexed-docs","title":"search-partial-indexed-docs"},{"id":"partitions","title":"PARTITIONS"},{"id":"search-raw-docid-encoding","title":"search-raw-docid-encoding"},{"id":"search-threads","title":"search-threads"},{"id":"search-io-threads","title":"search-io-threads"},{"id":"search-tiered-hnsw-buffer-limit","title":"search-tiered-hnsw-buffer-limit"},{"id":"search-timeout","title":"search-timeout"},{"id":"search-topology-validation-timeout","title":"search-topology-validation-timeout"},{"id":"search-union-iterator-heap","title":"search-union-iterator-heap"},{"id":"upgrade_index","title":"UPGRADE_INDEX"},{"id":"search-vss-max-resize","title":"search-vss-max-resize"},{"id":"search-workers-priority-bias-threshold","title":"search-workers-priority-bias-threshold"},{"id":"search-workers","title":"search-workers"},{"id":"search-on-oom","title":"search-on-oom"}],"id":"redis-search-configuration-parameters","title":"Redis Search configuration parameters"},{"id":"set-configuration-parameters-at-module-load-time-deprecated","title":"Set configuration parameters at module load-time (deprecated)"},{"id":"set-configuration-parameters-at-run-time-for-supported-parameters-deprecated","title":"Set configuration parameters at run-time (for supported parameters, deprecated)"}]}
,
"codeExamples": []
}
```
> [!NOTE]
> As of Redis 8 in Redis Open Source (Redis 8), configuration parameters for Redis Search are now set in the following ways:
> * At load time via your `redis.conf` file.
> * At run time (where applicable) using the [`CONFIG SET`](https://redis.io/docs/latest/commands/config-set) command.
>
> Also, Redis 8 persists Redis Search configuration parameters just like any other configuration parameters (e.g., using the [`CONFIG REWRITE`](https://redis.io/docs/latest/commands/config-rewrite) command).
## Redis Search configuration parameters
The following table summarizes which configuration parameters can be set at run-time, the versions in which each parameter is available, and compatibility with Redis Software and Redis Cloud.
The version columns indicate availability per Redis Query Engine module version (2.6, 2.8, and 2.10) and per Redis Open Source version (8.0, 8.2, 8.4, and 8.10). In those columns, ✅ means the parameter is available, ❌ means it is not available, and :warning: means it is deprecated (but still accepted) in that version.
#### Table part 1 of 2, rows 1-10
| Parameter name
(version < 8.0) | Parameter name
(version ≥ 8.0) | 2.6 | 2.8 | 2.10 | 8.0 | 8.2 |
| :------- | :------- | :----: | :----: | :----: | :----: | :----: |
| BG_INDEX_SLEEP_GAP | [search-bg-index-sleep-gap](#search-bg-index-sleep-gap) | ✅ | ✅ | ✅ | ✅ | ✅ |
| BG_INDEX_SLEEP_DURATION_US | [search-bg-index-sleep-duration-us](#search-bg-index-sleep-duration-us) | ❌ | ❌ | ❌ | ❌ | ✅ |
| CONCURRENT_WRITE_MODE | Removed in v2.10. | ✅ | ✅ | ❌ | ❌ | ❌ |
| CONN_PER_SHARD | [search-conn-per-shard](#search-conn-per-shard) | ❌ | ✅ | ✅ | ✅ | ✅ |
| CURSOR_MAX_IDLE | [search-cursor-max-idle](#search-cursor-max-idle) | ✅ | ✅ | ✅ | ✅ | ✅ |
| CURSOR_REPLY_THRESHOLD | [search-cursor-reply-threshold](#search-cursor-reply-threshold) | ✅ | ✅ | ✅ | ✅ | ✅ |
| DEFAULT_DIALECT | [search-default-dialect](#search-default-dialect) | ✅ | ✅ | ✅ | ✅ | ✅ |
| EXTLOAD | [search-ext-load](#search-ext-load) | ✅ | ✅ | ✅ | ✅ | ✅ |
| FORK_GC_CLEAN_THRESHOLD | [search-fork-gc-clean-threshold](#search-fork-gc-clean-threshold) | ✅ | ✅ | ✅ | ✅ | ✅ |
| FORK_GC_RETRY_INTERVAL | [search-fork-gc-retry-interval](#search-fork-gc-retry-interval) | ✅ | ✅ | ✅ | ✅ | ✅ |
#### Table part 1 of 2, rows 11-20
| Parameter name
(version < 8.0) | Parameter name
(version ≥ 8.0) | 2.6 | 2.8 | 2.10 | 8.0 | 8.2 |
| :------- | :------- | :----: | :----: | :----: | :----: | :----: |
| FORK_GC_RUN_INTERVAL | [search-fork-gc-run-interval](#search-fork-gc-run-interval) | ✅ | ✅ | ✅ | ✅ | ✅ |
| FORKGC_SLEEP_BEFORE_EXIT | [search-fork-gc-sleep-before-exit](#search-fork-gc-sleep-before-exit) | ✅ | ✅ | ✅ | ✅ | ✅ |
| FRISOINI | [search-friso-ini](#search-friso-ini) | ✅ | ✅ | ✅ | ✅ | ✅ |
| [GC_POLICY](#gc_policy) | There is no matching `CONFIG` parameter. | ✅ | ✅ | ✅ | ✅ | ✅ |
| GCSCANSIZE | [search-gc-scan-size](#search-gc-scan-size) | ✅ | ✅ | ✅ | ✅ | ✅ |
| INDEX_CURSOR_LIMIT | [search-index-cursor-limit](#search-index-cursor-limit) | ✅ | ✅ | ✅ | ✅ | ✅ |
| INDEX_THREADS | Removed in v2.10. | ✅ | ✅ | ❌ | ❌ | ❌ |
| MAXAGGREGATERESULTS | [search-max-aggregate-results](#search-max-aggregate-results) | ✅ | ✅ | ✅ | ✅ | ✅ |
| MAXDOCTABLESIZE | [search-max-doctablesize](#search-max-doctablesize) | ✅ | ✅ | ✅ | ✅ | ✅ |
| MAXEXPANSIONS | [search-max-expansions](#search-max-expansions) | ✅ | ✅ | ✅ | ✅ | ✅ |
#### Table part 1 of 2, rows 21-30
| Parameter name
(version < 8.0) | Parameter name
(version ≥ 8.0) | 2.6 | 2.8 | 2.10 | 8.0 | 8.2 |
| :------- | :------- | :----: | :----: | :----: | :----: | :----: |
| MAXPREFIXEXPANSIONS | [search-max-prefix-expansions](#search-max-prefix-expansions) | ✅ | ✅ | ✅ | ✅ | ✅ |
| MAXSEARCHRESULTS | [search-max-search-results](#search-max-search-results) | ✅ | ✅ | ✅ | ✅ | ✅ |
| _MAX_FOREGROUND_TIMEOUT_LIMIT | [search-_max-foreground-timeout-limit](#search-_max-foreground-timeout-limit) | ❌ | ❌ | ❌ | ❌ | ❌ |
| MIN_OPERATION_WORKERS | [search-min-operation-workers](#search-min-operation-workers) | ❌ | ❌ | ✅ | ✅ | ✅ |
| MIN_PHONETIC_TERM_LEN | [search-min-phonetic-term-len](#search-min-phonetic-term-len) | ✅ | ✅ | ✅ | ✅ | ✅ |
| MINPREFIX | [search-min-prefix](#search-min-prefix) | ✅ | ✅ | ✅ | ✅ | ✅ |
| MINSTEMLEN | [search-min-stem-len](#search-min-stem-len) | ❌ | ❌ | ✅ | ✅ | ✅ |
| MULTI_TEXT_SLOP | [search-multi-text-slop](#search-multi-text-slop) | ✅ | ✅ | ✅ | ✅ | ✅ |
| NO_MEM_POOLS | [search-no-mem-pools](#search-no-mem-pools) | ✅ | ✅ | ✅ | ✅ | ✅ |
| NOGC | [search-no-gc](#search-no-gc) | ✅ | ✅ | ✅ | ✅ | ✅ |
#### Table part 1 of 2, rows 31-40
| Parameter name
(version < 8.0) | Parameter name
(version ≥ 8.0) | 2.6 | 2.8 | 2.10 | 8.0 | 8.2 |
| :------- | :------- | :----: | :----: | :----: | :----: | :----: |
| ON_TIMEOUT | [search-on-timeout](#search-on-timeout) | ✅ | ✅ | ✅ | ✅ | ✅ |
| PARTIAL_INDEXED_DOCS | [search-partial-indexed-docs](#search-partial-indexed-docs) | ✅ | ✅ | ✅ | ✅ | ✅ |
| [PARTITIONS](#partitions) | There is no matching `CONFIG` parameter. | ✅ | ✅ | ✅ | ✅ | ✅ |
| RAW_DOCID_ENCODING | [search-raw-docid-encoding](#search-raw-docid-encoding) | ✅ | ✅ | ✅ | ✅ | ✅ |
| SEARCH_THREADS | [search-threads](#search-threads) | ✅ | ✅ | ✅ | ✅ | ✅ |
| SEARCH_IO_THREADS | [search-io-threads](#search-io-threads) | ❌ | ❌ | ❌ | ❌ | ❌ |
| TIERED_HNSW_BUFFER_LIMIT | [search-tiered-hnsw-buffer-limit](#search-tiered-hnsw-buffer-limit) | ❌ | ✅ | ✅ | ✅ | ✅ |
| TIMEOUT | [search-timeout](#search-timeout) | ✅ | ✅ | ✅ | ✅ | ✅ |
| TOPOLOGY_VALIDATION_TIMEOUT | [search-topology-validation-timeout](#search-topology-validation-timeout) | ❌ | ❌ | ✅ | ✅ | ✅ |
| UNION_ITERATOR_HEAP | [search-union-iterator-heap](#search-union-iterator-heap) | ✅ | ✅ | ✅ | ✅ | ✅ |
#### Table part 1 of 2, rows 41-50
| Parameter name
(version < 8.0) | Parameter name
(version ≥ 8.0) | 2.6 | 2.8 | 2.10 | 8.0 | 8.2 |
| :------- | :------- | :----: | :----: | :----: | :----: | :----: |
| [UPGRADE_INDEX](#upgrade_index) | There is no matching `CONFIG` parameter. | ✅ | ✅ | ✅ | ✅ | ✅ |
| VSS_MAX_RESIZE | [search-vss-max-resize](#search-vss-max-resize) | ✅ | ✅ | ✅ | ✅ | ✅ |
| WORKERS_PRIORITY_BIAS_THRESHOLD | [search-workers-priority-bias-threshold](#search-workers-priority-bias-threshold) | ❌ | ❌ | ✅ | ✅ | ✅ |
| WORKERS | [search-workers](#search-workers) | ❌ | ❌ | ✅ | ✅ | ✅ |
| OSS_GLOBAL_PASSWORD | Deprecated in v8.0.0. Replace with the `masterauth` password. | ✅ | ✅ | ✅ | :warning: | :warning: |
| MT_MODE | Deprecated in v8.0.0. Use search-workers. | ❌ | ✅ | ✅ | :warning: | :warning: |
| PRIVILEGED_THREADS_NUM | Deprecated in v8.0.0. Use search-workers-priority-bias-threshold. | ❌ | ✅ | ✅ | :warning: | :warning: |
| WORKER_THREADS | Deprecated in v8.0.0. Use search-min-operation-workers. | ❌ | ✅ | ✅ | :warning: | :warning: |
| SAFEMODE | Deprecated in v1.6.0. This is now the default setting. | :warning: | :warning: | ❌ | ❌ | ❌ |
| FORK_GC_CLEAN_NUMERIC_EMPTY_NODES | Deprecated in v8.0.0. | ✅ | ✅ | ✅ | :warning: | :warning: |
#### Table part 2 of 2, rows 1-10
| Parameter name
(version < 8.0) | 8.4 | 8.10 | Run-time | Redis
Software | Redis
Cloud |
| :------- | :----: | :----: | :------- | :------- | :------- |
| BG_INDEX_SLEEP_GAP | ✅ | ✅ | :white_large_square: | ✅ Supported
| ❌ Flexible & Annual
❌ Free & Fixed |
| BG_INDEX_SLEEP_DURATION_US | ✅ | ✅ | :white_large_square: | | |
| CONCURRENT_WRITE_MODE | ❌ | ❌ | | | |
| CONN_PER_SHARD | ✅ | ✅ | :white_check_mark: | | |
| CURSOR_MAX_IDLE | ✅ | ✅ | :white_check_mark: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
| CURSOR_REPLY_THRESHOLD | ✅ | ✅ | :white_check_mark: | | |
| DEFAULT_DIALECT | ✅ | ✅ | :white_check_mark: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
| EXTLOAD | ✅ | ✅ | :white_large_square: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
| FORK_GC_CLEAN_THRESHOLD | ✅ | ✅ | :white_check_mark: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
| FORK_GC_RETRY_INTERVAL | ✅ | ✅ | :white_check_mark: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
#### Table part 2 of 2, rows 11-20
| Parameter name
(version < 8.0) | 8.4 | 8.10 | Run-time | Redis
Software | Redis
Cloud |
| :------- | :----: | :----: | :------- | :------- | :------- |
| FORK_GC_RUN_INTERVAL | ✅ | ✅ | :white_check_mark: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
| FORKGC_SLEEP_BEFORE_EXIT | ✅ | ✅ | :white_check_mark: | | |
| FRISOINI | ✅ | ✅ | :white_large_square: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
| [GC_POLICY](#gc_policy) | ✅ | ✅ | :white_large_square: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
| GCSCANSIZE | ✅ | ✅ | :white_large_square: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
| INDEX_CURSOR_LIMIT | ✅ | ✅ | :white_large_square: | | |
| INDEX_THREADS | ❌ | ❌ | | | |
| MAXAGGREGATERESULTS | ✅ | ✅ | :white_check_mark: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
| MAXDOCTABLESIZE | ✅ | ✅ | :white_large_square: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
| MAXEXPANSIONS | ✅ | ✅ | :white_check_mark: | | |
#### Table part 2 of 2, rows 21-30
| Parameter name
(version < 8.0) | 8.4 | 8.10 | Run-time | Redis
Software | Redis
Cloud |
| :------- | :----: | :----: | :------- | :------- | :------- |
| MAXPREFIXEXPANSIONS | ✅ | ✅ | :white_check_mark: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
| MAXSEARCHRESULTS | ✅ | ✅ | :white_check_mark: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
| _MAX_FOREGROUND_TIMEOUT_LIMIT | ❌ | ✅ | :white_check_mark: | | |
| MIN_OPERATION_WORKERS | ✅ | ✅ | :white_check_mark: | | |
| MIN_PHONETIC_TERM_LEN | ✅ | ✅ | :white_check_mark: | | |
| MINPREFIX | ✅ | ✅ | :white_check_mark: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
| MINSTEMLEN | ✅ | ✅ | :white_check_mark: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
| MULTI_TEXT_SLOP | ✅ | ✅ | :white_large_square: | | |
| NO_MEM_POOLS | ✅ | ✅ | :white_large_square: | | |
| NOGC | ✅ | ✅ | :white_large_square: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
#### Table part 2 of 2, rows 31-40
| Parameter name
(version < 8.0) | 8.4 | 8.10 | Run-time | Redis
Software | Redis
Cloud |
| :------- | :----: | :----: | :------- | :------- | :------- |
| ON_TIMEOUT | ✅ | ✅ | :white_check_mark: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
| PARTIAL_INDEXED_DOCS | ✅ | ✅ | :white_large_square: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
| [PARTITIONS](#partitions) | ✅ | ✅ | :white_large_square: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
| RAW_DOCID_ENCODING | ✅ | ✅ | :white_large_square: | | |
| SEARCH_THREADS | ✅ | ✅ | :white_large_square: | | |
| SEARCH_IO_THREADS | ✅ | ✅ | :white_large_square: | | |
| TIERED_HNSW_BUFFER_LIMIT | ✅ | ✅ | :white_large_square: | | |
| TIMEOUT | ✅ | ✅ | :white_check_mark: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
| TOPOLOGY_VALIDATION_TIMEOUT | ✅ | ✅ | :white_check_mark: | | |
| UNION_ITERATOR_HEAP | ✅ | ✅ | :white_check_mark: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
#### Table part 2 of 2, rows 41-50
| Parameter name
(version < 8.0) | 8.4 | 8.10 | Run-time | Redis
Software | Redis
Cloud |
| :------- | :----: | :----: | :------- | :------- | :------- |
| [UPGRADE_INDEX](#upgrade_index) | ✅ | ✅ | :white_large_square: | ✅ Supported
| ✅ Flexible & Annual
❌ Free & Fixed |
| VSS_MAX_RESIZE | ✅ | ✅ | :white_check_mark: | | |
| WORKERS_PRIORITY_BIAS_THRESHOLD | ✅ | ✅ | :white_large_square: | | |
| WORKERS | ✅ | ✅ | :white_check_mark: | | |
| OSS_GLOBAL_PASSWORD | :warning: | :warning: | :white_large_square: | ✅ Supported
| ❌ Flexible & Annual
❌ Free & Fixed |
| MT_MODE | :warning: | :warning: | :white_large_square: | | |
| PRIVILEGED_THREADS_NUM | :warning: | :warning: | :white_large_square: | | |
| WORKER_THREADS | :warning: | :warning: | :white_large_square: | | |
| SAFEMODE | ❌ | ❌ | :white_large_square: | | |
| FORK_GC_CLEAN_NUMERIC_EMPTY_NODES | :warning: | :warning: | :white_large_square: | | |
> [!NOTE]
> Parameter names for Redis Open Source versions < 8.0, while deprecated, will still be supported in Redis 8.
---
### search-bg-index-sleep-gap
The number of iterations to run while performing background indexing before `usleep(1)` (sleep for 1 microsecond) is called, ensuring that Redis can process other commands.
Type: integer
Valid range: `[1 .. 4294967295]`
Default: `100`
### search-bg-index-sleep-duration-us
Added in the 8.2 maintenance line (v8.2.12) and the 8.4 maintenance line (v8.4.9). Not available in Redis Open Source 8.0, and not present in the initial 8.2.0 or 8.4.0 releases.
The sleep duration (in microseconds) used during background indexing. During background indexing (triggered by `FT.CREATE` on existing keys), Redis periodically sleeps to allow the main thread to process commands. This parameter controls how long each sleep lasts. Works in conjunction with [`search-bg-index-sleep-gap`](#search-bg-index-sleep-gap), which controls how many iterations occur between sleeps.
Type: integer
Valid range: `[1 .. 999999]`
Default: `1`
### search-conn-per-shard
The number of connections to each shard in a cluster.
If `0`, the number of connections is set to `search-workers` + 1.
Type: integer
Valid range: `[0 .. 9,223,372,036,854,775,807]`
Default: `0`
### search-cursor-max-idle
The maximum idle time (in ms) that can be set to the [cursor api](https://redis.io/docs/latest/develop/ai/search-and-query/advanced-concepts/aggregations#cursor-api).
Type: integer
Valid range: `[0 .. 9,223,372,036,854,775,807]`
Default: `300000`
### search-cursor-reply-threshold
The maximum number of replies to accumulate before triggering `_FT.CURSOR READ` on the shards.
Type: integer
Valid range: `[1 .. 9,223,372,036,854,775,807]`
Default: `1`
### search-default-dialect
The default
[DIALECT](https://redis.io/docs/latest/develop/ai/search-and-query/advanced-concepts/dialects)
to be used by [`FT.CREATE`](https://redis.io/docs/latest/commands/ft.create), [`FT.AGGREGATE`](https://redis.io/docs/latest/commands/ft.aggregate), [`FT.EXPLAIN`](https://redis.io/docs/latest/commands/ft.explain), [`FT.EXPLAINCLI`](https://redis.io/docs/latest/commands/ft.explaincli), and [`FT.SPELLCHECK`](https://redis.io/docs/latest/commands/ft.spellcheck).
See [Query dialects](https://redis.io/docs/latest/develop/ai/search-and-query/advanced-concepts/dialects)
for more information.
Default: `1`
### search-ext-load
If present, Redis will try to load an extension dynamic library from the specified file path.
See [Extensions](https://redis.io/docs/latest/develop/ai/search-and-query/administration/extensions) for details.
Type: string
Default: not set
### search-fork-gc-clean-numeric-empty-nodes
Clean empty nodes from numeric tree.
Type: boolean
Default: `TRUE`
### search-fork-gc-clean-threshold
The fork GC will only start to clean when the number of uncleaned documents exceeds this threshold, otherwise it will skip this run.
Type: integer
Valid range: `[1 .. 9,223,372,036,854,775,807]`
Default: `100`
### search-fork-gc-retry-interval
Interval (in seconds) in which Redis will retry to run fork GC in case of a failure.
This setting can only be combined with the [`search-gc-policy`](#search-gc-policy) `FORK` setting.
Type: integer
Valid range: `[1 .. 9,223,372,036,854,775,807]`
Default: `5`
### search-fork-gc-run-interval
Interval (in seconds) between two consecutive fork GC runs.
This setting can only be combined with the [`search-gc-policy`](#search-gc-policy) `FORK` setting.
Type: integer
Valid range: `[1 .. 9,223,372,036,854,775,807]`
Default: `30`
### search-fork-gc-sleep-before-exit
The number of seconds for the fork GC to sleep before exit. This value should always be set to 0 except when testing.
Type: integer
Valid range: `[1 .. 9,223,372,036,854,775,807]`
Default: `0`
### search-friso-ini
If present, load the custom Chinese dictionary from the specified path. See [Using custom dictionaries](https://redis.io/docs/latest/develop/ai/search-and-query/advanced-concepts/chinese#using-custom-dictionaries) for more details.
Type: string
Default: not set
### GC_POLICY
The garbage collection policy. The two supported policies are:
* FORK: uses a forked thread for garbage collection (v1.4.1 and above). This is the default GC policy since v1.6.1 and is ideal for general purpose workloads.
* LEGACY: uses a synchronous, in-process fork. This is ideal for read-heavy and append-heavy workloads with very few updates/deletes. Deprecated in v2.6.0.
Note: When `GC_POLICY` is set to `FORK`, it can be combined with the `search-fork-gc-run-interval` and `search-fork-gc-retry-interval` settings.
Type: string
Valid values: `FORK` or `DEFAULT`
Default: `FORK`
### search-gc-scan-size
The bulk size of the internal GC used for cleaning up indexes.
Type: integer
Valid range: `[1 .. 9,223,372,036,854,775,807]`
Redis Open Source default: `100`
Redis Software default: `-1` (unlimited)
Redis Cloud defaults:
- Flexible & Annual: `-1` (unlimited)
- Free & Fixed: `10000`
### search-index-cursor-limit
Available in Redis Query Engine v2.6.24, v2.8.21, and v2.10.9 and their later maintenance releases, and in Redis Open Source 8.0 and later.
The maximum number of cursors that can be opened, per shard, at any given time. Cursors can be opened by the user via [`FT.AGGREGATE WITHCURSOR`](https://redis.io/docs/latest/commands/ft.aggregate). Cursors are also opened internally by Redis Search for long-running queries. Once `INDEX_CURSOR_LIMIT` is reached, any further attempts to open a cursor will result in an error.
> [!NOTE] Notes
> * Caution should be used in modifying this parameter. Every open cursor results in additional memory usage.
> * Cursor usage should be regulated first by use of [`FT.CURSOR DEL`](https://redis.io/docs/latest/commands/ft.cursor-del) and/or [`MAXIDLE`](https://redis.io/docs/latest/commands/ft.aggregate) prior to modifying `INDEX_CURSOR_LIMIT`
> * See [Cursor API](https://redis.io/docs/latest/develop/ai/search-and-query/advanced-concepts/aggregations#cursor-api) for more details.
Type: integer
Default: `128`
### search-max-aggregate-results
The maximum number of results to be returned by the `FT.AGGREGATE` command if `LIMIT` is used. It also caps the `offset` and `count` of the [`COLLECT` reducer's](https://redis.io/docs/latest/develop/ai/search-and-query/advanced-concepts/aggregations#collect) `LIMIT`.
Type: integer
Valid range: `[1 .. 9,223,372,036,854,775,807]`
Redis Open Source default: `-1` (unlimited)
Redis Software default: `-1` (unlimited)
Redis Cloud defaults:
- Flexible & Annual: `-1` (unlimited)
- Free & Fixed: `10000`
### search-max-doctablesize
The maximum size of the internal hash table used for storing documents.
Note: this configuration option doesn't limit the number of documents that can be stored. It only affects the hash table internal array maximum size.
Decreasing this property can decrease the memory overhead in cases where the index holds a small number of documents that are constantly updated.
Type: integer
Valid range: `[1 .. 18,446,744,073,709,551,615]`
Default: `1000000`
### search-max-expansions
This parameter is an alias for [search-max-prefix-expansions](#search-max-prefix-expansions).
### search-max-prefix-expansions
The maximum number of expansions allowed for query prefixes.
The maximum number of expansions allowed for query prefixes. Setting it too high can cause performance issues. If `search-max-prefix-expansions` is reached, the query will continue with the first acquired results. The configuration is applicable for all affix queries including prefix, suffix, and infix (contains) queries.
Type: integer
Valid range: `[1 .. 9,223,372,036,854,775,807]`
Default: `200`
### search-max-search-results
The maximum number of results to be returned by the `FT.SEARCH` command if `LIMIT` is used. Set it to `-1` to remove the limit.
Type: integer
Valid range: `[1 .. 9,223,372,036,854,775,807]`
Redis Open Source default: `1000000`
Redis Software default: `1000000`
Redis Cloud defaults:
- Flexible & Annual: `1000000`
- Free & Fixed: `10000`
### search-_max-foreground-timeout-limit
Available in Redis Search 8.10 and later.
Sets the hard upper bound, in milliseconds, for the effective query timeout when
[`search-workers`](#search-workers) is `0`. The effective timeout is either a query's
`TIMEOUT` value or, when the query doesn't specify one, the value inherited from
[`search-timeout`](#search-timeout).
If the effective timeout exceeds this limit, Redis caps it instead of rejecting the query.
This also applies to `TIMEOUT 0`, which normally means unlimited. RESP3 clients receive a
`MaxTimeoutCapped` warning when the timeout is capped. The limit applies to
[`FT.SEARCH`](https://redis.io/docs/latest/commands/ft.search),
[`FT.AGGREGATE`](https://redis.io/docs/latest/commands/ft.aggregate),
[`FT.CURSOR READ`](https://redis.io/docs/latest/commands/ft.cursor-read), and
[`FT.HYBRID`](https://redis.io/docs/latest/commands/ft.hybrid).
Set this parameter to `0` to disable the limit. The limit is also inactive when
`search-workers` is greater than `0`.
Changes to this parameter, `search-timeout`, and `search-workers` are accepted and logged
at notice level regardless of their current combination. Redis evaluates the settings and
applies the limit when each query runs.
The legacy `FT.CONFIG` name is `_MAX_FOREGROUND_TIMEOUT_LIMIT`.
Type: integer
Valid range: `[0 .. 9,223,372,036,854,775,807]`
Default: `60000`
### search-min-operation-workers
The number of worker threads to use for background tasks when the server is in an operation event.
Type: integer
Valid range: `[0 .. 8192]`
Default: `4`
### search-min-phonetic-term-len
The minimum length of term to be considered for phonetic matching.
Type: integer
Valid range: `[1 .. 9,223,372,036,854,775,807]`
Default: `3`
### search-min-prefix
The minimum number of characters allowed for prefix queries (for example, hel*). Setting it to `1` can reduce performance.
Type: integer
Valid range: `[1 .. 9,223,372,036,854,775,807]`
Default: `2`
### search-min-stem-len
The minimum word length to stem. Setting it lower than `4` can reduce performance.
Type: integer
Valid range: `[2 .. 4,294,967,295]`
Redis Open Source default: `4`
Redis Software and Redis Cloud default: `2`
### search-multi-text-slop
Set the delta that is used to increase positional offsets between array slots for multi text values.
This will allow you to control the level of separation between phrases in different array slots; related to the `SLOP` parameter of `FT.SEARCH` command.
Type: integer
Valid range: `[0 .. 4,294,967,295]`
Default: `100`
### search-no-mem-pools
Set Redis Search to run without memory pools.
Type: boolean
Default: `FALSE`
### search-no-gc
If set to `TRUE`, garbage collection is disabled for all indexes.
Type: boolean
Default: `FALSE`
### search-on-timeout
The response policy for queries that exceed their effective timeout can be one of the following:
* `RETURN`: this policy will return the top results accumulated by the query until it timed out.
* `RETURN_STRICT`: like `RETURN`, returns the partial results accumulated when a query exceeds the timeout instead of failing, but strictly enforces the configured timeout as a hard deadline. This matters most in clustered deployments: with `RETURN`, the first shard to time out aborts the whole query early; with `RETURN_STRICT`, the coordinator keeps gathering results from all shards up to the deadline and then returns whatever accumulated at that point. Available in Redis Query Engine 8.10 and later.
* `FAIL`: will return an error when the query exceeds the timeout value.
Type: string
Valid values: `RETURN`, `RETURN_STRICT`, `FAIL`
Default: `RETURN`
### search-partial-indexed-docs
Available in Redis Query Engine 2.0 and later.
Enable/disable the Redis command filter. The filter optimizes partial updates of hashes
and may avoid re-indexing the hash if changed fields are not part of the schema.
The Redis command filter will be executed upon each Redis command. Though the filter is
optimized, this will introduce a small increase in latency on all commands.
This configuration is best used with partially indexed documents where the non-indexed fields are updated frequently.
Type: integer
Valid values: `0` (false), `1` (true)
Default: `0`
### PARTITIONS
The number of coordinator partitions to use in a clustered deployment (Redis Software,
Redis Cloud, or Redis Open Source in cluster mode). This parameter is deprecated and
immutable: any value passed to it is ignored, and the number of partitions is always
determined automatically.
Type: string
Valid values: `AUTO`
Default: `AUTO`
### search-raw-docid-encoding
Disable compression for DocID inverted indexes to boost CPU performance.
Type: boolean
Default: `FALSE`
### search-threads
Sets the number of search threads in the coordinator thread pool.
Type: integer
### search-io-threads
Sets the number of threads used in the coordinator to run I/O tasks with other shards.
Type: integer
Valid range: `[1 .. 256]`
Default: 1
### search-tiered-hnsw-buffer-limit
Used for setting the buffer limit threshold for vector tiered HNSW indexes. If Redis is using `WORKERS` for indexing, and the number of vectors waiting in the buffer to be indexed exceeds this limit, new vectors are inserted directly into HNSW.
Type: integer
Valid range: `[0 .. 9,223,372,036,854,775,807]`
Default: `1024`
### search-timeout
The default amount of time in milliseconds that a search query is allowed to run when the query doesn't specify its own `TIMEOUT`. A query-specific `TIMEOUT` overrides this value, so `search-timeout` is a default, not a ceiling. When [`search-_max-foreground-timeout-limit`](#search-_max-foreground-timeout-limit) is active, it provides the ceiling for the effective timeout.
If the effective timeout is exceeded, Redis returns the top results accumulated so far, or an error depending on the policy set with [`search-on-timeout`](#search-on-timeout). The timeout can be disabled by setting it to `0`.
> [!NOTE] Notes
> * `search-timeout` refers to query time only.
> * Parsing the query is not counted towards `search-timeout`.
> * If `search-timeout` was not reached during the search, finalizing operations such as loading document content or reducers continue.
Type: integer
Value range: `[1 .. 9,223,372,036,854,775,807]`
Redis Open Source default: `500`
Redis Software default: `500`
Redis Cloud defaults:
- Flexible & Annual: `500`
- Free & Fixed: `100`
### search-topology-validation-timeout
Sets the timeout in milliseconds for topology validation. After this timeout, any pending requests will be processed, even if the topology is not fully connected. A value of `0` means no timeout.
Type: integer
Valid range: `[1 .. 9,223,372,036,854,775,807]`
Default: `30000`
### search-union-iterator-heap
The minimum number of iterators in a union at which the iterator will switch to a heap based implementation.
Type: integer
Valid range: `[1 .. 9,223,372,036,854,775,807]`
Default: `20`
### UPGRADE_INDEX
There is no matching `CONFIG` parameter for `UPGRADE_INDEX`; it is available only as an `FT.CONFIG` parameter or as a module load-time argument.
Relevant only when loading an v1.x RDB file. Specify the argument for upgrading the index.
This configuration setting is a special configuration option introduced to upgrade indexes from v1.x Redis Search versions, otherwise known as legacy indexes. This configuration option needs to be given for each legacy index, followed by the index name and all valid options for the index description (also referred to as the `ON` arguments for following hashes) as described on [FT.CREATE](https://redis.io/docs/latest/commands/ft.create) command page.
Type: string
Default: there is no default for index name, and the other arguments have the same defaults as with the [`FT.CREATE`](https://redis.io/docs/latest/commands/ft.create) command.
**Example**
```
UPGRADE_INDEX idx PREFIX 1 tt LANGUAGE french LANGUAGE_FIELD MyLang SCORE 0.5 SCORE_FIELD MyScore
PAYLOAD_FIELD MyPayload UPGRADE_INDEX idx1
```
> [!NOTE] Notes
> * If the RDB file does not contain a legacy index that's specified in the configuration, a warning message will be added to the log file, and loading will continue.
> * If the RDB file contains a legacy index that wasn't specified in the configuration, loading will fail and the server won't start.
### search-vss-max-resize
Available in Redis Query Engine 2.4.8 and later.
The maximum memory resize (in bytes) for vector indexes.
The maximum memory resize (in bytes) for vector indexes. This value will override default memory limits if you need to allow for a large [`BLOCK_SIZE`](https://redis.io/docs/latest/develop/ai/search-and-query/vectors#create-a-vector-index).
Type: integer
Valid range: `[0 .. 4,294,967,295]`
Default: `0`
### search-workers-priority-bias-threshold
The number of high priority tasks to be executed at any given time by the worker thread pool before executing low priority tasks. After this number of high priority tasks are being executed, the worker thread pool will execute high and low priority tasks alternately.
Type: integer
Valid range: `[1 .. 9,223,372,036,854,775,807]`
Default: `1`
### search-workers
The number of worker threads to use for query processing and background tasks.
Type: integer
Valid range: `[0 .. 8192]`
Default: `0`
### search-on-oom
Specifies the response policy for queries when the server's current memory usage exceeds the configured [maxmemory](https://redis.io/docs/latest/develop/reference/eviction/#maxmem) limit.
* `IGNORE`: Execute the query regardless of current memory usage.
* `RETURN`: In cluster mode, the query returns partial results from shards that did not exceed the memory limit. Shards that exceed the limit will not contribute results.
* `FAIL`: Will return an error if memory usage exceeds the memory limit.
Type: string
Valid values: `IGNORE`, `RETURN`, `FAIL`
Default: `IGNORE`
> [!NOTE] Notes
> To prevent potential out-of-memory conditions, it is recommended that you set this parameter to FAIL or RETURN rather than IGNORE.
## Set configuration parameters at module load-time (deprecated)
These methods are deprecated beginning with Redis 8.
Setting configuration parameters at load-time is done by appending arguments after the `--loadmodule` argument when starting a server from the command line, or after the `loadmodule` directive in a Redis config file. For example:
In [redis.conf](https://redis.io/docs/latest/operate/oss_and_stack/management/config):
```
loadmodule ./redisearch.so [OPT VAL]...
```
From the [Redis CLI](https://redis.io/docs/latest/develop/tools/cli), using the [MODULE LOAD](https://redis.io/docs/latest/commands/module-load) command:
```
127.0.0.6379> MODULE LOAD redisearch.so [OPT VAL]...
```
From the command line:
```
$ redis-server --loadmodule ./redisearch.so [OPT VAL]...
```
## Set configuration parameters at run-time (for supported parameters, deprecated)
These methods are deprecated beginning with Redis 8.
Redis Search exposes the `FT.CONFIG` endpoint to allow for the setting and retrieval of configuration parameters at run-time.
To set the value of a configuration parameter at run-time (for supported parameters), simply run:
```sh
FT.CONFIG SET OPT1 VAL1
```
Similarly, you can retrieve current configuration parameter values using:
```sh
FT.CONFIG GET OPT1
FT.CONFIG GET *
```
Values set using [`FT.CONFIG SET`](https://redis.io/docs/latest/commands/ft.config-set) are not persisted after server restart.