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XACK

Last updated 
XACK key group id [id ...]
Group
Stream
Complexity
O(1) per ID
Arity
-4 (at least 4 words, counting the command name)
Flags
write, fast
Keys
first 1, last 1, step 1
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On-Premise
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XACK marks entries as processed for the consumer group group: they are removed from the group’s pending entries list, whichever consumer held them. It returns how many of the IDs were pending and are now acknowledged.

Acknowledging does not delete the entries from the stream. Use XDEL or XTRIM for that.

When the stream and the group exist, all IDs are checked before any is acknowledged.

Return value

Section titled “Return value”
Case RESP2 RESP3
Always Integer: the number of entries acknowledged Integer

The reply is 0 when the key or the group does not exist, or when none of the IDs was pending.

Error replies: ERR Invalid stream ID specified as stream command argument, and WRONGTYPE if the key holds another type.

Examples

Section titled “Examples”
127.0.0.1:6379> XADD tasks 1700000000000-0 job email
"1700000000000-0"
127.0.0.1:6379> XGROUP CREATE tasks workers 0
OK
127.0.0.1:6379> XREADGROUP GROUP workers alice STREAMS tasks >
1) 1) "tasks"
   2) 1) 1) "1700000000000-0"
         2) 1) "job"
            2) "email"
127.0.0.1:6379> XACK tasks workers 1700000000000-0
(integer) 1
127.0.0.1:6379> XACK tasks workers 1700000000000-0
(integer) 0

Compatibility

Section titled “Compatibility”

Same as Redis 7 and Valkey 8.

See also

Section titled “See also”

XREADGROUP, XPENDING, XCLAIM