Horton

Re: Yet another fast GiST build

Heikki Linnakangas <hlinnaka@iki.fi>

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From: Heikki Linnakangas <hlinnaka@iki.fi>
To: Andrey Borodin <x4mmm@yandex-team.ru>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Justin Pryzby <pryzby@telsasoft.com>, Darafei Komяpa 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
Date: 2020-10-07T12:38:20Z
Lists: pgsql-hackers 
On 07/10/2020 15:27, Andrey Borodin wrote:
> Here's draft patch with implementation of sortsupport for ints and floats.

> +static int
> +gbt_int4_cmp(Datum a, Datum b, SortSupport ssup)
> +{
> +	int32KEY   *ia = (int32KEY *) DatumGetPointer(a);
> +	int32KEY   *ib = (int32KEY *) DatumGetPointer(b);
> +
> +	if (ia->lower == ib->lower)
> +	{
> +		if (ia->upper == ib->upper)
> +			return 0;
> +
> +		return (ia->upper > ib->upper) ? 1 : -1;
> +	}
> +
> +	return (ia->lower > ib->lower) ? 1 : -1;
> +}

We're only dealing with leaf items during index build, so the 'upper' 
and 'lower' should always be equal here, right? Maybe add a comment and 
an assertion on that.

(It's pretty sad that the on-disk representation is identical for leaf 
and internal items, because that wastes a lot of disk space, but that's 
way out of scope for this patch.)

- Heikki

Commits

  1. Add sortsupport for gist_btree opclasses, for faster index builds.

  2. pageinspect: Fix relcache leak in gist_page_items().

  3. Fix test failure with wal_level=minimal.

  4. Enhance nbtree index tuple deletion.

  5. Fix portability issues in the new gist pageinspect test.

  6. Add functions to 'pageinspect' to inspect GiST indexes.

  7. Fix missing validation for the new GiST sortsupport functions.

  8. Fix compilation warning in xlog.c

  9. Set right-links during sorted GiST index build.

  10. Fix checksum calculation in the new sorting GiST build.

  11. Add support for building GiST index by sorting.