doc: redis文档阅读

中间件/redis/redis.md

@@ -120,6 +120,9 @@
         - [Trimming with consumer group Awareness](#trimming-with-consumer-group-awareness)
       - [Special IDs in streams API](#special-ids-in-streams-api)
       - [Persistence, replication and message safety](#persistence-replication-and-message-safety)
+      - [removing single items from a stream](#removing-single-items-from-a-stream)
+        - [XDEL](#xdel)
+        - [Enhanced deletion with XDELEX](#enhanced-deletion-with-xdelex)
 
 
 # redis
@@ -2150,4 +2153,33 @@ redis streams和consumer groups将会被持久化，并且`replicated using the
   - 在发生故障转移时，redis仅会执行`best effort check`，从而转移到`replica which is the most updated`，在某些失败场景下，转移到的replica仍然可能缺失部分数据
 
 
+#### removing single items from a stream
+stream同样支持`removing items from the middle of a stream`，尽管stream为append-only data structure, 但是该功能仍然在许多场景下十分有用。
+
+##### XDEL
+`XDEL`命令的使用示例如下所示：
+```redis-cli
+> XRANGE race:italy - + COUNT 2
+1) 1) "1692633198206-0"
+   2) 1) "rider"
+      2) "Wood"
+2) 1) "1692633208557-0"
+   2) 1) "rider"
+      2) "Henshaw"
+> XDEL race:italy 1692633208557-0
+(integer) 1
+> XRANGE race:italy - + COUNT 2
+1) 1) "1692633198206-0"
+   2) 1) "rider"
+      2) "Wood"
+```
+
+##### Enhanced deletion with XDELEX
+从redis 8.2开始，`XDELEX`命令对entry删除提供了增强的控制，尤其是针对consumer groups。和其他enhanced commands一样，其支持`KEEPREF, DELREF, ACKED`三种模式：
+```redis-cli
+XDELEX mystream ACKED IDS 2 1692633198206-0 1692633208557-0
+```
+- 在使用`ACKED`模式时，仅在entries已经被所有consumer groups都acknowledged之后，才能够对entries进行删除
+- 在使用`DELREF`时，会删除所有的consumer group reference
+- 在使用`KEEPREF`时，