Re: Anyone seen this kind of lock pileup?

On 11/17/10 18:37, Josh Berkus wrote:
> All,
>
> Having an interesting issue on one 8.4 database. Due to poor application
> design, the application is requesting 8-15 exclusive (update) locks on
> the same row on parallel connections pretty much simultaneously (i.e. <
> 50ms apart).
>
> What's odd about this is that the resulting "lock pileup" takes a
> mysterious 2-3.5 seconds to clear, despite the fact that none of the
> connections are *doing* anything during that time, nor are there
> deadlock errors. In theory at least, the locks should clear out in
> reverse order in less than a second; none of the individual statements
> takes more than 10ms to execute.

Just a random guess: a timeout-supported livelock? (of course if there
is any timeout-and-retry protocol going on and the timeout intervals are
non-randomized).