• antirez's avatar
    Safer script stop condition on OOM. · c6c71abe
    antirez authored
    Here the idea is that we do not want freeMemoryIfNeeded() to propagate a
    DEL command before the script and change what happens in the script
    execution once it reaches the slave. For example see this potential
    issue (in the words of @soloestoy):
    
    On master, we run the following script:
    
        if redis.call('get','key')
        then
            redis.call('set','xxx','yyy')
        end
        redis.call('set','c','d')
    
    Then when redis attempts to execute redis.call('set','xxx','yyy'), we call freeMemoryIfNeeded(), and the key may get deleted, and because redis.call('set','xxx','yyy') has already been executed on master, this script will be replicated to slave.
    
    But the slave received "DEL key" before the script, and will ignore maxmemory, so after that master has xxx and c, slave has only one key c.
    
    Note that this patch (and other related work) was authored collaboratively in
    issue #5250 with the help of @soloestoy and @oranagra.
    
    Related to issue #5250.
    c6c71abe
scripting.c 87.6 KB