| From: | David Rowley <drowley(at)postgresql(dot)org> |
|---|---|
| To: | pgsql-committers(at)lists(dot)postgresql(dot)org |
| Subject: | pgsql: Clarify the 'rows' parameter in create_append_path |
| Date: | 2024-02-15 00:13:50 |
| Message-ID: | E1raPNu-006GlZ-3O@gemulon.postgresql.org |
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| Thread: | |
| Lists: | pgsql-committers |
Clarify the 'rows' parameter in create_append_path
This is extracted from a larger patch to improve the UNION planner.
While working on that, I found myself having to check what the 'rows'
parameter is for. It's not obvious that passing a negative number is the
way to have the rows estimate calculated and to find that out you need
to read code in create_append_path() and in cost_append().
Discussion: https://postgr.es/m/CAApHDvpb_63XQodmxKUF8vb9M7CxyUyT4sWvEgqeQU-GB7QFoQ@mail.gmail.com
Branch
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master
Details
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https://git.postgresql.org/pg/commitdiff/87027cb55bf7b33416880f7f5f5e67f4202d5881
Modified Files
--------------
src/backend/optimizer/util/pathnode.c | 4 ++++
1 file changed, 4 insertions(+)
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