Horton

Re: Showing primitive index scan count in EXPLAIN ANALYZE (for skip scan and SAOP scans)

Peter Geoghegan <pg@bowt.ie>

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From: Peter Geoghegan <pg@bowt.ie>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Matthias van de Meent <boekewurm+postgres@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2025-03-06T18:58:04Z
Lists: pgsql-hackers 
On Thu, Mar 6, 2025 at 1:54 PM Robert Haas <robertmhaas@gmail.com> wrote:
> Hmm, it seems weird that you can't get a hold of that structure to me.
> Why can't you just go find it in the DSM?

Sorry, I was unclear.

One reason is that there isn't necessarily anything to find.
Certainly, when I try this out with a debugger, even the B-Tree scan
doesn't have doesn't even have IndexScanDescData.parallel_scan set. It
isn't actually a parallel B-Tree scan. It is a
serial/non-parallel-aware index scan that is run from a parallel
worker, and feeds its output into a gather merge node despite all
this.

-- 
Peter Geoghegan

Commits

  1. Show index search count in EXPLAIN ANALYZE, take 2.

  2. Show index search count in EXPLAIN ANALYZE.

  3. Allow usage of match_orclause_to_indexcol() for joins

  4. Fix nbtree pgstats accounting with parallel scans.

  5. Enhance nbtree ScalarArrayOp execution.

  6. Fix EXPLAIN ANALYZE of hash join when the leader doesn't participate.