Horton

RE: [Patch] Optimize dropping of relation buffers using dlist

tsunakawa.takay@fujitsu.com <tsunakawa.takay@fujitsu.com>

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From: "tsunakawa.takay@fujitsu.com" <tsunakawa.takay@fujitsu.com>
To: "k.jamison@fujitsu.com" <k.jamison@fujitsu.com>
Cc: 'Amit Kapila' <amit.kapila16@gmail.com>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Andres Freund <andres@anarazel.de>, Robert Haas <robertmhaas@gmail.com>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2020-09-28T08:07:40Z
Lists: pgsql-hackers 
	From: Jamison, Kirk/ジャミソン カーク <k.jamison@fujitsu.com>
> Is my understanding above correct?

No.  I simply meant DropRelFileNodeBuffers() calls the following function, and avoids the optimization if it returns InvalidBlockNumber.


BlockNumber
smgrcachednblocks(SMgrRelation reln, ForkNumber forknum)
{
	return reln->smgr_cached_nblocks[forknum];
}


Regards
Takayuki Tsunakawa

Commits

  1. Fix size overflow in calculation introduced by commits d6ad34f3 and bea449c6.

  2. Optimize DropRelFileNodesAllBuffers() for recovery.

  3. Optimize DropRelFileNodeBuffers() for recovery.

  4. Cache smgrnblocks() results in recovery.

  5. Add a check to prevent overwriting valid data if smgrnblocks() gives a