watch, unwatch
Description
Watches a key for modifications by another client. If the key is modified between WATCH
and EXEC
, the MULTI/EXEC transaction will fail (return FALSE
). unwatch
cancels all the watching of all keys by this client.
监控一个KEY是否被其他的客户端修改。如果KEY在调用watch()和exec()之间被修改,那么批量处理最终的exec()执行将失败。unwatch()取消对于所有KEY值的监控操作针对于这个Redis实例。通过一些实验,这个函数的效果其实并没有那么好,或者说不能够准确的去监控。
Parameters
keys: a list of keys
Example
$redis->watch('x'); /* long code here during the execution of which other clients could well modify `x` */ $ret = $redis->multi() ->incr('x') ->exec(); /* $ret = FALSE if x has been modified between the call to WATCH and the call to EXEC. */