Horton

Re: An out-of-date comment in nodeIndexonlyscan.c

David Rowley <dgrowleyml@gmail.com>

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From: David Rowley <dgrowleyml@gmail.com>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Ashwin Agrawal <aagrawal@pivotal.io>, Pg Hackers <pgsql-hackers@postgresql.org>, Heikki Linnakangas <hlinnaka@iki.fi>, Kevin Grittner <kgrittn@gmail.com>
Date: 2021-06-13T12:54:18Z
Lists: pgsql-hackers 
On Mon, 14 Jun 2021 at 00:02, Thomas Munro <thomas.munro@gmail.com> wrote:
> Here's a highly experimental patch I came up with that seems to
> produce the right results in simple cases, without (yet) involving the
> planner.

+ /* Find all equality quals. */
+ for (int i = 0; i < n_scan_keys; ++i)
+ {
+ if (scan_keys[i].sk_strategy == BTEqualStrategyNumber)
+ attnos[nattnos++] = scan_keys[i].sk_attno;
+ }
+
+ /* Are all attributes covered? */
+ /* XXX is this check enough or do we need to work harder? */
+ qsort(attnos, nattnos, sizeof(AttrNumber), compare_int16);
+ nattnos = qunique(attnos, nattnos, sizeof(AttrNumber), compare_int16);
+ if (nattnos == index->rd_index->indnkeyatts)

I think a more optimal and nicer way of doing that would be setting
bits in a Bitmapset then checking bms_num_members is equal to
n_scan_keys.

David

Commits

  1. Block ALTER INDEX/TABLE index_name ALTER COLUMN colname SET (options)

  2. Fix misleading comment in nodeIndexonlyscan.c.

  3. Eliminate xmin from hash tag for predicate locks on heap tuples.

  4. Fix serializable mode with index-only scans.