On Thu, 17 Jan 2019 at 17:18, Amit Langote <langote_amit...@lab.ntt.co.jp> wrote: > > On 2019/01/04 9:53, David Rowley wrote: > > Without PREPAREd statements, if the planner itself was unable to prune > > the partitions it would already have obtained the lock during > > planning, so AcquireExecutorLocks(), in this case, would bump into the > > local lock hash table entry and forego trying to obtain the lock > > itself. That's not free, but it's significantly faster than obtaining > > a lock. > > Hmm, AcquireExecutorLocks is only called if prepared statements are used > and that too if a generic cached plan is reused. > > GetCachedPlan -> CheckCachedPlan -> AcquireExecutorLocks
ah okay. Thanks for the correction, but either way, it's really only useful when run-time pruning prunes partitions before initialising the Append/MergeAppend node. -- David Rowley http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
