Date: Sun, 20 Sep 2020 17:44:46 -0500
From: Justin Pryzby <pryzby@telsasoft.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>,
	"Andrey M. Borodin" <x4mmm@yandex-team.ru>,
	Darafei =?utf-8?Q?Kom=D1=8Fpa?= Praliaskouski <me@komzpa.net>,
	Pavel Borisov <pashkin.elfe@gmail.com>,
	Thomas Munro <thomas.munro@gmail.com>,
	Michael Paquier <michael@paquier.xyz>,
	Alexander Korotkov <a.korotkov@postgrespro.ru>,
	pgsql-hackers@postgresql.org
Subject: Re: Yet another fast GiST build
Message-ID: <20200920224446.GF30557@telsasoft.com>
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On Sun, Sep 20, 2020 at 05:10:05PM -0400, Tom Lane wrote:
> I wrote:
> > It appears that hyrax (CLOBBER_CACHE_ALWAYS) is not very happy
> > with this:
> > https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=hyrax&dt=2020-09-19%2021%3A27%3A23
> 
> I reproduced that and traced it to a missing RelationOpenSmgr call.
> Fixed now.

This also appears to break checksums.

postgres=#  CREATE TABLE pvactst (i INT, a INT[], p POINT) with (autovacuum_enabled = off);
postgres=#  CREATE INDEX gist_pvactst ON pvactst USING gist (p);
postgres=#  INSERT INTO pvactst SELECT i, array[1,2,3], point(i, i+1) FROM generate_series(1,1000) i;
WARNING:  page verification failed, calculated checksum 34313 but expected 0
ERROR:  invalid page in block 0 of relation base/12859/16389

I was able to make this work like so:

@@ -449,6 +450,7 @@ gist_indexsortbuild(GISTBuildState *state)
 
        /* Write out the root */
        PageSetLSN(pagestate->page, GistBuildLSN);
+       PageSetChecksumInplace(pagestate->page, GIST_ROOT_BLKNO, state->indexrel->rd_smgr);
        smgrwrite(state->indexrel->rd_smgr, MAIN_FORKNUM, GIST_ROOT_BLKNO,
                          pagestate->page, true);
        if (RelationNeedsWAL(state->indexrel))
@@ -555,6 +557,7 @@ gist_indexsortbuild_flush_ready_pages(GISTBuildState *state)
 
                PageSetLSN(page, GistBuildLSN);
 
+               PageSetChecksumInplace(page, state->pages_written, state->indexrel->rd_smgr);
                smgrextend(state->indexrel->rd_smgr,
                                   MAIN_FORKNUM,
                                   state->pages_written++,

-- 
Justin