From: | Etsuro Fujita <efujita(at)postgresql(dot)org> |
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To: | pgsql-committers(at)lists(dot)postgresql(dot)org |
Subject: | pgsql: postgres_fdw: Fix cost estimation for aggregate pushdown. |
Date: | 2019-05-09 09:42:22 |
Message-ID: | E1hOfZG-0004td-54@gemulon.postgresql.org |
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Lists: | pgsql-committers |
postgres_fdw: Fix cost estimation for aggregate pushdown.
In commit 7012b132d0, which added support for aggregate pushdown in
postgres_fdw, the expense of evaluating the final scan/join target
computed by make_group_input_target() was not accounted for at all in
costing aggregate pushdown paths with local statistics. The right fix
for this would be to have a separate upper stage to adjust the final
scan/join relation (see comments for apply_scanjoin_target_to_paths());
but for now, fix by adding the tlist eval cost when costing aggregate
pushdown paths with local statistics.
Apply this to HEAD only to avoid destabilizing existing plan choices.
Author: Etsuro Fujita
Reviewed-By: Antonin Houska
Discussion: https://postgr.es/m/5C66A056.60007%40lab.ntt.co.jp
Branch
------
master
Details
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https://git.postgresql.org/pg/commitdiff/edbcbe277d795ecc339b0e4fa29bae42ce1a7be9
Modified Files
--------------
contrib/postgres_fdw/postgres_fdw.c | 16 +++++++++++++---
src/backend/optimizer/plan/planner.c | 4 ++++
2 files changed, 17 insertions(+), 3 deletions(-)
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