On Tue, 26 Mar 2019 at 21:23, Tsunakawa, Takayuki <tsunakawa.ta...@jp.fujitsu.com> wrote: > Thank you David for explaining. Although I may not understand the effect of > "speeding up planning with partitions" patch, this patch takes effect even > without it. That is, perform the following in the same session: > > 1. SELECT count(*) FROM table; on a table with many partitions. That bloats > the LocalLockHash. > 2. PREPARE a point query, e.g., SELECT * FROM table WHERE pkey = $1; > 3. EXECUTE the PREPAREd query repeatedly, with each EXECUTE in a separate > transaction. Without the patch, each transaction's LockReleaseAll() has to > scan the bloated large hash table.
Oh. I think I see what you're saying. Really the table in #2 would have to be some completely different table that's not partitioned. I think in that case it should make a difference. -- David Rowley http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
