pgsql: Further adjustments to Hashagg EXPLAIN ANALYZE output - Mailing list pgsql-committers

From David Rowley
Subject pgsql: Further adjustments to Hashagg EXPLAIN ANALYZE output
Date
Msg-id E1jqQQP-00047y-19@gemulon.postgresql.org
Whole thread Raw
List pgsql-committers
Further adjustments to Hashagg EXPLAIN ANALYZE output

The "Disk Usage" and "HashAgg Batches" properties in the EXPLAIN ANALYZE
output for HashAgg were previously only shown if the number of batches
was greater than 0.  Here we change this so that these properties are
always shown for EXPLAIN ANALYZE formats other than "text".  The idea here
is that since the HashAgg could have spilled to disk if there had been
more data or groups to aggregate, then it's relevant that we're clear in
the EXPLAIN ANALYZE output when no spilling occurred in this particular
execution of the given plan.

For the "text" EXPLAIN format, we still hide these properties when no
spilling occurs.  This EXPLAIN format is designed to be easy for humans
to read.  To maintain the readability we have a higher threshold for which
properties we display for this format.

Discussion: https://postgr.es/m/CAApHDvo_dmNozQQTmN-2jGp1vT%3Ddxx7Q0vd%2BMvD1cGpv2HU%3DSg%40mail.gmail.com
Backpatch-through: 13, where the hashagg spilling code was added.

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/40efbf8706cdd96e06bc4d1754272e46d9857875

Modified Files
--------------
src/backend/commands/explain.c | 21 +++++++--------------
1 file changed, 7 insertions(+), 14 deletions(-)


pgsql-committers by date:

Previous
From: Michael Meskes
Date:
Subject: pgsql: Fix ecpg crash with bytea and cursor variables.
Next
From: David Rowley
Date:
Subject: pgsql: Further adjustments to Hashagg EXPLAIN ANALYZE output