Adding upstream version 1.9.1.upstream/1.9.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 37 insertions, 0 deletions

diff --git a/iredis/data/commands/xtrim.md b/iredis/data/commands/xtrim.md
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+`XTRIM` trims the stream to a given number of items, evicting older items (items
+with lower IDs) if needed. The command is conceived to accept multiple trimming
+strategies, however currently only a single one is implemented, which is
+`MAXLEN`, and works exactly as the `MAXLEN` option in `XADD`.
+
+For example the following command will trim the stream to exactly the latest
+1000 items:
+
+```
+XTRIM mystream MAXLEN 1000
+```
+
+It is possible to give the command in the following special form in order to
+make it more efficient:
+
+```
+XTRIM mystream MAXLEN ~ 1000
+```
+
+The `~` argument between the **MAXLEN** option and the actual count means that
+the user is not really requesting that the stream length is exactly 1000 items,
+but instead it could be a few tens of entries more, but never less than 1000
+items. When this option modifier is used, the trimming is performed only when
+Redis is able to remove a whole macro node. This makes it much more efficient,
+and it is usually what you want.
+
+@return
+
+@integer-reply, specifically:
+
+The command returns the number of entries deleted from the stream.
+
+```cli
+XADD mystream * field1 A field2 B field3 C field4 D
+XTRIM mystream MAXLEN 2
+XRANGE mystream - +
+```