add redis cache doc

Signed-off-by: Jimmie Han <hanjinming@outlook.com>

docs/components/query-frontend.md

@@ -95,6 +95,34 @@ config:
   expiration: 24h
 ```
 
+#### Redis
+
+The default redis config is:
+
+```yaml mdox-exec="go run scripts/cfggen/main.go --name=queryfrontend.RedisResponseCacheConfig"
+type: REDIS
+config:
+  addr: ""
+  username: ""
+  password: ""
+  dial_timeout: 5s
+  read_timeout: 3s
+  write_timeout: 3s
+  pool_size: 100
+  min_idle_conns: 10
+  idle_timeout: 5m0s
+  max_conn_age: 0s
+  max_get_multi_concurrency: 100
+  get_multi_batch_size: 100
+  max_set_multi_concurrency: 100
+  set_multi_batch_size: 100
+  expiration: 24h0m0s
+```
+
+`expiration` specifies redis cache valid time. If set to 0s, so using a default of 24 hours expiration time.
+
+Other cache configuration parameters, you can refer to [redis-index-cache](store.md#redis-index-cache).
+
 ### Slow Query Log
 
 Query Frontend supports `--query-frontend.log-queries-longer-than` flag to log queries running longer than some duration.

docs/components/store.md

@@ -304,11 +304,54 @@ While the remaining settings are **optional**:
 - `dns_provider_update_interval`: the DNS discovery update interval.
 - `auto_discovery`: whether to use the auto-discovery mechanism for memcached.
 
+### Redis index cache
+
+The `memcached` index cache allows to use [Redis](https://redis.io) as cache backend. This cache type is configured using `--index-cache.config-file` to reference the configuration file or `--index-cache.config` to put yaml config directly:
+
+```yaml mdox-exec="go run scripts/cfggen/main.go --name=cacheutil.RedisClientConfig"
+type: REDIS
+config:
+  addr: ""
+  username: ""
+  password: ""
+  dial_timeout: 5s
+  read_timeout: 3s
+  write_timeout: 3s
+  pool_size: 100
+  min_idle_conns: 10
+  idle_timeout: 5m0s
+  max_conn_age: 0s
+  max_get_multi_concurrency: 100
+  get_multi_batch_size: 100
+  max_set_multi_concurrency: 100
+  set_multi_batch_size: 100
+```
+
+The **required** settings are:
+
+- `addr`: redis server address.
+
+While the remaining settings are **optional**:
+
+- `username`: the username to connect redis, only redis 6.0 and grater need this field.
+- `password`: the password to connect redis.
+- `dial_timeout`: the redis dial timeout.
+- `read_timeout`: the redis read timeout.
+- `write_timeout`: the redis write timeout.
+- `pool_size`: maximum number of socket connections.
+- `min_idle_conns`: specifies the minimum number of idle connections which is useful when establishing new connection is slow.
+- `idle_timeout`: amount of time after which client closes idle connections. Should be less than server's timeout.
+- `max_conn_age`: connection age at which client retires (closes) the connection.
+- `max_get_multi_concurrency`: specifies the maximum number of concurrent GetMulti() operations.
+- `get_multi_batch_size`: specifies the maximum size per batch for mget.
+- `max_set_multi_concurrency`: specifies the maximum number of concurrent SetMulti() operations.
+- `set_multi_batch_size`: specifies the maximum size per batch for pipeline set.
+
 ## Caching Bucket
 
 Thanos Store Gateway supports a "caching bucket" with [chunks](../design.md#chunk) and metadata caching to speed up loading of [chunks](../design.md#chunk) from TSDB blocks. To configure caching, one needs to use `--store.caching-bucket.config=<yaml content>` or `--store.caching-bucket.config-file=<file.yaml>`.
 
-Both memcached and in-memory cache "backend"s are supported:
+memcached/in-memory/redis cache "backend"s are supported:
 
 ```yaml
 type: MEMCACHED # Case-insensitive
@@ -333,7 +376,8 @@ metafile_content_ttl: 24h
 metafile_max_size: 1MiB
 ```
 
-`config` field for memcached supports all the same configuration as memcached for [index cache](#memcached-index-cache). `addresses` in the config field is a **required** setting
+- `config` field for memcached supports all the same configuration as memcached for [index cache](#memcached-index-cache). `addresses` in the config field is a **required** setting
+- `config` field for redis supports all the same configuration as redis for [index cache](#redis-index-cache).
 
 Additional options to configure various aspects of [chunks](../design.md#chunk) cache are available:
 

scripts/cfggen/main.go

@@ -65,11 +65,13 @@ var (
 	indexCacheConfigs = map[storecache.IndexCacheProvider]interface{}{
 		storecache.INMEMORY:  storecache.InMemoryIndexCacheConfig{},
 		storecache.MEMCACHED: cacheutil.MemcachedClientConfig{},
+		storecache.REDIS:     cacheutil.DefaultRedisClientConfig,
 	}
 
 	queryfrontendCacheConfigs = map[queryfrontend.ResponseCacheProvider]interface{}{
 		queryfrontend.INMEMORY:  queryfrontend.InMemoryResponseCacheConfig{},
 		queryfrontend.MEMCACHED: queryfrontend.MemcachedResponseCacheConfig{},
+		queryfrontend.REDIS:     queryfrontend.DefaultRedisConfig,
 	}
 )