But I think if I can set the timeout for 1 or 2 seconds the probability of the race condition should be much less.
Thanks, Kevin On Wednesday, September 25, 2013 9:25:50 PM UTC+8, Trond Norbye wrote: > > A distributed system may always have race conditions and you need to find > a solution for them. Your delayed delete would not solve that because you > don't know how slow the other stuff may be. > > Trond > On Sep 25, 2013 3:13 PM, "Kevin Fang" <kevint...@gmail.com <javascript:>> > wrote: > >> Hi guys, >> >> I have one question about the 'delete' command. >> Before 1.4.0, the command used to be >> delete <key> [<time>] [noreply]\r\n >> there is a <time> parameter which supports lingering delete. >> But after 1.4.0 the feature was completely removed. Now there is no >> <time> parameter. >> >> However, I think this parameter is useful. It could avoid the data >> inconsistency that caused by the reorder of 'delete' and 'set' operation. >> Think about this senario. >> 1. App server A 'get' key k1 from the cache server. Not exist. It's a >> Cache miss >> 2. App server A query database. Then try to 'set' the k1 to the cache >> server >> 3. App server B update the record related to k1 in the database. Then try >> to 'delete' k1 on all cache servers. >> 4. For some network issue the 'set' operation sent by A is very slow. It >> reaches the cache after the 'delete' operation sent by B. >> 5. After the 'set' operation. The value of k1 becomes stale data, and may >> never be updated any more. >> >> My question is. If there is no <time> parameter for delete operation. How >> to avoid the above senario? What's the best practice? >> >> Thanks, >> Kevin >> >> -- >> >> --- >> You received this message because you are subscribed to the Google Groups >> "memcached" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to memcached+...@googlegroups.com <javascript:>. >> For more options, visit https://groups.google.com/groups/opt_out. >> > -- --- You received this message because you are subscribed to the Google Groups "memcached" group. To unsubscribe from this group and stop receiving emails from it, send an email to memcached+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
