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	Mon, 17 Mar 2025 11:22:57 -0400
From: Tom Lane <tgl@sss.pgh.pa.us>
To: kimaidou <kimaidou@gmail.com>
cc: postgres performance list <pgsql-performance@postgresql.org>
Subject: Re: Bad perf when using DECLARE CURSOR on big table
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kimaidou <kimaidou@gmail.com> writes:
> I have seen that this DECLARE has bad perf compared to a simple SQL query :

> Simple SQL query
> =====
> https://explain.dalibo.com/plan/042bc4dc2449adfe
> 96ms

> DECLARE CURSOR for the same query
> =====
> https://explain.dalibo.com/plan/bh83fc0db500a79g#
> 171 031 ms !!

Raising cursor_tuple_fraction would probably help this case.

			regards, tom lane