Re: Speed up transaction completion faster after many relations are accessed in a transaction
Tom Lane <tgl@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
To: David Rowley <david.rowley@2ndquadrant.com>
Cc: "Tsunakawa, Takayuki" <tsunakawa.takay@jp.fujitsu.com>,
"pgsql-hackers@lists.postgresql.org"
<pgsql-hackers@lists.postgresql.org>
Date: 2019-02-18T23:57:50Z
Lists: pgsql-hackers
David Rowley <david.rowley@2ndquadrant.com> writes: > On Tue, 19 Feb 2019 at 12:42, Tom Lane <tgl@sss.pgh.pa.us> wrote: >> My own thought about how to improve this situation was just to destroy >> and recreate LockMethodLocalHash at transaction end (or start) >> if its size exceeded $some-value. Leaving it permanently bloated seems >> like possibly a bad idea, even if we get rid of all the hash_seq_searches >> on it. > That seems like a good idea. Although, it would be good to know that > it didn't add too much overhead dropping and recreating the table when > every transaction happened to obtain more locks than $some-value. If > it did, then maybe we could track the average locks per of recent > transactions and just ditch the table after the locks are released if > the locks held by the last transaction exceeded the average * > 1.something. No need to go near shared memory to do that. Yeah, I'd deliberately avoided saying how we'd choose $some-value ;-). Making it adaptive might not be a bad plan. regards, tom lane
Commits
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Reorder LOCALLOCK structure members to compact the size
- 28988a84cf19 12.0 landed
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Be more careful to not lose sync in the FE/BE protocol.
- 2b3a8b20c2da 9.5.0 cited