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Diffstat (limited to 'iredis/data/commands/xack.md')
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diff --git a/iredis/data/commands/xack.md b/iredis/data/commands/xack.md new file mode 100644 index 0000000..76b7c13 --- /dev/null +++ b/iredis/data/commands/xack.md @@ -0,0 +1,25 @@ +The `XACK` command removes one or multiple messages from the _pending entries +list_ (PEL) of a stream consumer group. A message is pending, and as such stored +inside the PEL, when it was delivered to some consumer, normally as a side +effect of calling `XREADGROUP`, or when a consumer took ownership of a message +calling `XCLAIM`. The pending message was delivered to some consumer but the +server is yet not sure it was processed at least once. So new calls to +`XREADGROUP` to grab the messages history for a consumer (for instance using an +ID of 0), will return such message. Similarly the pending message will be listed +by the `XPENDING` command, that inspects the PEL. + +Once a consumer _successfully_ processes a message, it should call `XACK` so +that such message does not get processed again, and as a side effect, the PEL +entry about this message is also purged, releasing memory from the Redis server. + +@return + +@integer-reply, specifically: + +The command returns the number of messages successfully acknowledged. Certain +message IDs may no longer be part of the PEL (for example because they have been +already acknowledge), and XACK will not count them as successfully acknowledged. + +```cli +XACK mystream mygroup 1526569495631-0 +``` |