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rhubarbgroup/redis-cache

A persistent object cache backend for WordPress powered by Redis. Supports Predis, PhpRedis, Relay, replication, sentinels, clustering and WP-CLI.

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README.md

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# Redis Object Cache for WordPress

A persistent object cache backend powered by Redis®¹. Supports [Predis](https://github.com/predis/predis/), [PhpRedis (PECL)](https://github.com/phpredis/phpredis), [Relay](https://relaycache.com), replication, sentinels, clustering and [WP-CLI](http://wp-cli.org/).

[![Redis Object Cache screenshots](/.wordpress-org/collage-sm.jpg?raw=true)](/.wordpress-org/collage.png?raw=true)

## Object Cache Pro

A **business class** Redis®¹ object cache backend. Truly reliable, highly optimized, fully customizable and with a dedicated engineer when you most need it.

* Rewritten for raw performance
* 100% WordPress API compliant
* Faster serialization and compression
* Easy debugging & logging
* Cache prefetching and advanced analytics
* Fully unit tested (100% code coverage)
* Optimized for WooCommerce, Jetpack & Yoast SEO
* [And much more...](https://objectcache.pro/?ref=oss&amp;utm_source=wp-plugin&amp;utm_medium=readme)

## Installation

To get started, please see the [installation instructions](INSTALL.md).

## FAQ & Troubleshooting

Answers to common questions and troubleshooting of common errors can be found in the [FAQ](FAQ.md).

## Configuration

The Redis Object Cache plugin comes with vast set of configuration options. If you're unsure how to use them read the [installation instructions](INSTALL.md).

| Configuration constant               | Default     | Description                                   |
| ------------------------------------ | ----------- | --------------------------------------------- |
| `WP_REDIS_HOST`                      | `127.0.0.1` | The hostname of the Redis server |
| `WP_REDIS_PORT`                      | `6379`      | The port of the Redis server |
| `WP_REDIS_PATH`                      |             | The path to the unix socket of the Redis server |
| `WP_REDIS_SCHEME`                    | `tcp`       | The scheme used to connect: `tcp` or `unix` |
| `WP_REDIS_DATABASE`                  | `0`         | The database used by the cache: `0-15` |
| `WP_REDIS_PREFIX`                    |             | The prefix used for all cache keys to avoid data collisions (replaces `WP_CACHE_KEY_SALT`), should be human readable and not a "salt" |
| `WP_REDIS_PASSWORD`                  |             | The password of the Redis server, supports Redis ACLs arrays: `['user', 'password']` |
| `WP_REDIS_MAXTTL`                    | `0`         | The maximum time-to-live of cache keys |
| `WP_REDIS_CLIENT`                    |             | The client used to communicate with Redis (defaults to `phpredis` when installed, otherwise `predis`), supports `phpredis`, `predis`, `relay` |
| `WP_REDIS_TIMEOUT`                   | `1`         | The connection timeout in seconds |
| `WP_REDIS_READ_TIMEOUT`              | `1`         | The timeout in seconds when reading/writing |
| `WP_REDIS_IGNORED_GROUPS`            | `[]`        | Groups that should not be cached between requests in Redis ([read more](FAQ.md#how-can-i-ignore-a-cache-group)) |

<details>
<summary>Advanced configuration options</summary>

| Configuration constant               | Default     | Description                                   |
| ------------------------------------ | ----------- | --------------------------------------------- |
| `WP_CACHE_KEY_SALT`                  |             | Deprecated. Replaced by `WP_REDIS_PREFIX` |
| `WP_REDIS_SSL_CONTEXT`               | `[]`        | TLS connection options for `tls` or `rediss` scheme |
| `WP_REDIS_FLUSH_TIMEOUT`             | `5`         | Experimental. The timeout in seconds when flushing |
| `WP_REDIS_RETRY_INTERVAL`            |             | The number of milliseconds between retries (PhpRedis only) |
| `WP_REDIS_PERSISTENT`                | `false`     | Whether to persistent connections. Optionally, accepts non-empty connection identifier string. |
| `WP_REDIS_GLOBAL_GROUPS`             | `[]`        | Additional groups that are considered global on multisite networks |
| `WP_REDIS_CHART_COLOR`               |             | Override admin metrics chart color using a hex value (`#RGB` or `#RRGGBB`) |
| `WP_REDIS_METRICS_MAX_TIME`          | `3600`      | The maximum number of seconds metrics should be stored |
| `WP_REDIS_IGBINARY`                  | `false`     | Whether to use the igbinary PHP extension for serialization |
| `WP_REDIS_DISABLED`                  | `false`     | Emergency switch to bypass the object cache without deleting the drop-in |
| `WP_REDIS_DISABLE_ADMINBAR`          | `false`     | Disables admin bar display |
| `WP_REDIS_DISABLE_METRICS`           | `false`     | Disables metrics collection and display |
| `WP_REDIS_DISABLE_DROPIN_CHECK`      | `false`     | Disables the extended drop-in write test |
| `WP_REDIS_DISABLE_DROPIN_AUTOUPDATE` | `false`     | Disables the drop-in auto-update |
| `WP_REDIS_DISABLE_GROUP_FLUSH`       | `false`     | Disables group flushing with Lua script and uses `flushdb` call instead |
| `WP_REDIS_DISABLE_BANNERS`           | `false`     | Disables promotional banners and notices |
| `WP_REDIS_DISABLE_COMMENT`           | `false`     | Disables HTML source comment |
| `WP_REDIS_LOAD_APEXCHARTS`           | `true`      | Whether to load the ApexCharts script |
| `WP_REDIS_MANAGER_CAPABILITY`        |             | The capability a user must have to manage the plugin |

</details>

<details>
<summary><em>Unsupported</em> configuration options</summary>

Options that exist, but **should not**, **may break without notice** in future releases and **won't receive any support** whatsoever from our team:

| Configuration constant        | Default     | Description                                                           |
| ----------------------------- | ----------- | --------------------------------------------------------------------- |
| `WP_REDIS_GRACEFUL`           | `false`     | Prevents exceptions from being thrown, but will cause data corruption |
| `WP_REDIS_SELECTIVE_FLUSH`    | `false`     | Uses terribly slow Lua script for flushing                            |
| `WP_REDIS_UNFLUSHABLE_GROUPS` | `[]`        | Uses terribly slow Lua script to prevent groups from being flushed    |

</details>

## Connections

<details>
<summary>Connecting over Unix socket</summary>

```php
define( 'WP_REDIS_SCHEME', 'unix' );
define( 'WP_REDIS_PATH', '/var/run/redis.sock' );
```

</details>

<details>
<summary>Connecting over TCP+TLS</summary>

```php
define( 'WP_REDIS_SCHEME', 'tls' );
define( 'WP_REDIS_HOST', 'master.ncit.ameaqx.use1.cache.amazonaws.com' );
define( 'WP_REDIS_PORT', 6379 );
```

Additional TLS/SSL stream connection options for connections can be defined using `WP_REDIS_SSL_CONTEXT`:

```php
define( 'WP_REDIS_SSL_CONTEXT', [
    'verify_peer' => false,
    'verify_peer_name' => false,
]);
```

</details>

<details>
<summary>Connecting using ACL authentication</summary>

```php
define( 'WP_REDIS_PASSWORD', [ 'username', 'password' ] );
```

</details>

## Scaling

Redis Object Cache offers various replication, sharding, cluster and sentinel setups to users with advanced technical knowledge of Redis and PHP, that have consulted the [Predis](https://github.com/predis/predis), [PhpRedis](https://github.com/phpredis/phpredis) or [Relay](https://relay.so/docs) documentation.

<details>
<summary>Relay</summary>

Relay is a next-generation cache that keeps a partial replica of Redis' dataset in PHP's memory for ridiculously fast lookups, especially when Redis Server is not on the same machine as WordPress.

```php
define( 'WP_REDIS_CLIENT', 'relay' );

define( 'WP_REDIS_HOST', '127.0.0.1' );
define( 'WP_REDIS_PORT', 6379 );

// when using Relay, each WordPress installation
// MUST a dedicated Redis database and unique prefix
define( 'WP_REDIS_DATABASE', 0 );
define( 'WP_REDIS_PREFIX', 'db3:' );

// consume less memory
define( 'WP_REDIS_IGBINARY', true );
```

</details>

<details>
<summary>Replication</summary>

<https://redis.io/docs/management/replication/>

```php
define( 'WP_REDIS_CLIENT', 'predis' );

define( 'WP_REDIS_SERVERS', [
    'tcp://127.0.0.1:6379?database=5&role=master',
    'tcp://127.0.0.2:6379?database=5&alias=replica-01',
] );
```

</details>

<details>
<summary>Sharding</summary>

This is a PhpRedis specific feature using [`RedisArray`](https://github.com/phpredis/phpredis/blob/develop/array.md).

```php
define( 'WP_REDIS_CLIENT', 'phpredis' );

define( 'WP_REDIS_SHARDS', [
    'tcp://127.0.0.1:6379?database=10&alias=shard-01',
    'tcp://127.0.0.2:6379?database=10&alias=shard-02',
    'tcp://127.0.0.3:6379?database=10&alias=shard-03',
] );
```

</details>

<details>
<summary>Redis Sentinel</summary>

<https://redis.io/docs/management/sentinel/>

```php
define( 'WP_REDIS_CLIENT', 'predis' );

define( 'WP_REDIS_SENTINEL', 'my-sentinel' );
define( 'WP_REDIS_SERVERS', [
    'tcp://127.0.0.1:5380',
    'tcp://127.0.0.2:5381',
    'tcp://127.0.0.3:5382',
] );
```

</details>

<details>
<summary>Redis Cluster</summary>

<https://redis.io/docs/management/scaling/>

```php
define( 'WP_REDIS_CLIENT', 'phpredis' );

define( 'WP_REDIS_CLUSTER', [
    'tcp://127.0.0.1:6379?alias=node-01',
    'tcp://127.0.0.2:6379?alias=node-02',
    'tcp://127.0.0.3:6379?alias=node-03',
] );
```

</details>

## WP CLI commands

Redis Object Cache has various WP CLI commands, for more information run `wp help redis`.

| Command                  | Description                                   |
| ------------------------ | --------------------------------------------- |
| `wp redis status`        | Shows the object cache status and diagnostics |
| `wp redis enable`        | Enables the object cache                      |
| `wp redis disable`       | Disables the object cache                     |
| `wp redis update-dropin` | Updates the object cache drop-in              |

## Actions & Filters

Redis Object Cache has various hooks and the commonly used ones are listed below.

| Filter / Action                         | Description |
| --------------------------------------- | ----------- |
| `redis_cache_expiration`                | Filters the cache expiration for individual keys |
| `redis_cache_validate_dropin`           | Filters whether the drop-in is valid |
| `redis_cache_add_non_persistent_groups` | Filters the groups to be marked as non persistent |
| `redis_cache_manager_capability`        | Filters the capability a user needs to manage the plugin |

## Footnotes

¹ Redis is a registered trademark of Redis Ltd. Any rights therein are reserved to Redis Ltd. Any use by Redis Object Cache is for referential purposes only and does not indicate any sponsorship, endorsement or affiliation between Redis and Redis Object Cache.

Repository info

Default branch: develop
Latest version: 3.0.0
Created: 2015-02-14
Last activity: 2026-10-08
License: GPL-3.0
Open issues: 12
Watchers: 19

Topics

cache php phpredis predis redis relay wordpress wordpress-plugin

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