CODEWITHSUNDEEP
synchronizationlockingmemcached
OneSolitaryNoob
OneSolitaryNoob

Reputation: 5767

Lock out a key in Memcache

I'm trying to find a way to prevent a particular key in memcache from being written for a specified period of time, e.g. 5 minutes.

I can imagine doing something like below, but it would require an extra "get" for every "set"

function lock($key,$expiration) {
  memcache::set($key,'DONTUSEME', $expiration);
}


function set_key($key,$val) {
  if(memcache::get($key) == 'DONETUSEME') {
     # no-op
  } else {
     memcache::set($key,$val);
  }
}

function get_key($key) {
   $val = memcache::get($key);
   if($val == 'DONTUSEME') {
      return '';
   } else {  
      return $val;
   }
}

Upvotes: 0

Views: 2159

Answers (2)

OneSolitaryNoob
OneSolitaryNoob

Reputation: 5767

A year later - memcache doesn't seem able to do this.

Redis definitely has locking functinoality, via SETNX. Redis is competitive with Memcache, performance-wise.

http://redis.io/commands/setnx

SETNX key value

Set key to hold string value if key does not exist. In that case, it is equal to SET. When key already holds a value, no operation is performed. SETNX is short for "SET if N ot e X ists.

Upvotes: 0

mikewied
mikewied

Reputation: 5343

Memcached does not allow you to lock keys. You could potentially look into Couchbase though since it does have a "get and lock" command and uses the same protocol as memcached. Couchbase is a database, but it contains a memcached caching layer on top. I can provide more details if you want to try this solution. There may also be other caching solutions that do implement a lock command, but I can not think of any off the top of my head.

Upvotes: 1

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