Proposal: add a debug message about using geqo

From: KAWAMOTO Masaya <kawamoto(at)sraoss(dot)co(dot)jp>
To: pgsql-hackers(at)postgresql(dot)org
Subject: Proposal: add a debug message about using geqo
Date: 2022-05-10 01:05:48
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During query tuning, users may want to check if GEQO is used or not
to generate a plan. However, users can not know it by simply counting
the number of tables that appear in SQL. I know we can know it by
enabling GEQO_DEBUG flag, but it needs recompiling, so I think it is

So, I would like to propose to add a debug level message that shows
when PostgreSQL use GEQO. That enables users to easily see it by
just changing log_min_messages.

Use cases are as follows:
- When investigating about the result of planning, user can determine
whether the plan is chosen by the standard planning or GEQO.

- When tuning PostgreSQL, user can determine the suitable value of
geqo_threshold parameter.

Best regards.

KAWAMOTO Masaya <kawamoto(at)sraoss(dot)co(dot)jp>
SRA OSS, Inc. Japan

Attachment Content-Type Size
debugmessage_about_geqo.patch application/octet-stream 709 bytes


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