Horton

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

Kyotaro Horiguchi <horikyota.ntt@gmail.com>

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From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
To: k.jamison@fujitsu.com
Cc: tsunakawa.takay@fujitsu.com, andres@anarazel.de, amit.kapila16@gmail.com, tgl@sss.pgh.pa.us, thomas.munro@gmail.com, robertmhaas@gmail.com, tomas.vondra@2ndquadrant.com, pgsql-hackers@postgresql.org
Date: 2020-11-26T07:40:17Z
Lists: pgsql-hackers 
At Thu, 26 Nov 2020 16:18:55 +0900 (JST), Kyotaro Horiguchi <horikyota.ntt@gmail.com> wrote in 
> +	/* Zero the array of blocks because these will all be dropped anyway */
> +	MemSet(firstDelBlocks, 0, sizeof(BlockNumber) * n * (MAX_FORKNUM + 1));
> 
> We don't need to prepare nforks, forks and firstDelBlocks for all
> relations before looping over relations.  In other words, we can fill
> in the arrays for a relation at every iteration of relations.

Or even we could call FindAndDropRelFileNodeBuffers() for each
forks. It dones't matter in the performance perspective whether the
function loops over forks or the function is called for each forks.

regrds.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center

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