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Diffstat (limited to 'iredis/data/commands/xgroup-create.md')
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1 files changed, 23 insertions, 0 deletions
diff --git a/iredis/data/commands/xgroup-create.md b/iredis/data/commands/xgroup-create.md new file mode 100644 index 0000000..f0f1606 --- /dev/null +++ b/iredis/data/commands/xgroup-create.md @@ -0,0 +1,23 @@ +This command creates a new consumer group uniquely identified by `<groupname>` for the stream stored at `<key>`. + +Every group has a unique name in a given stream. When a consumer group with the same name already exists, the command returns a `-BUSYGROUP` error. + +The command's `<id>` argument specifies the last delivered entry in the stream from the new group's perspective. +The special ID `$` means the ID of the last entry in the stream, but you can provide any valid ID instead. +For example, if you want the group's consumers to fetch the entire stream from the beginning, use zero as the starting ID for the consumer group: + + XGROUP CREATE mystream mygroup 0 + +By default, the `XGROUP CREATE` command insists that the target stream exists and returns an error when it doesn't. +However, you can use the optional `MKSTREAM` subcommand as the last argument after the `<id>` to automatically create the stream (with length of 0) if it doesn't exist: + + XGROUP CREATE mystream mygroup $ MKSTREAM + +The optional `entries_read` named argument can be specified to enable consumer group lag tracking for an arbitrary ID. +An arbitrary ID is any ID that isn't the ID of the stream's first entry, its last entry or the zero ("0-0") ID. +This can be useful you know exactly how many entries are between the arbitrary ID (excluding it) and the stream's last entry. +In such cases, the `entries_read` can be set to the stream's `entries_added` subtracted with the number of entries. + +@return + +@simple-string-reply: `OK` on success. |