From: Tom Lane <tgl@sss.pgh.pa.us>
To: hu_yajun@qq.com
cc: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #17936: Memory Leak when OPERATOR FAMILY use LANGUAGE SQL
 function
In-reply-to: <17936-ccbf22f31c04b6cf@postgresql.org>
References: <17936-ccbf22f31c04b6cf@postgresql.org>
Comments: In-reply-to PG Bug reporting form <noreply@postgresql.org>
	message dated "Tue, 16 May 2023 13:16:43 -0000"
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Date: Tue, 16 May 2023 09:52:08 -0400
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PG Bug reporting form <noreply@postgresql.org> writes:
>    I guess I found a memory leak problem when OPERATOR FAMILY use LANGUAGE
> SQL function.
> ** Problem **
> I build postgresql with tag REL_15_3, and run following SQL.
> --
> CREATE OR REPLACE FUNCTION pg_catalog.text_cmp_bpchar(text, bpchar)
> RETURNS int4
> AS'select pg_catalog.bttextcmp($1, $2::text)'
> LANGUAGE SQL IMMUTABLE STRICT PARALLEL SAFE;

> ALTER OPERATOR FAMILY text_ops USING btree ADD
> OPERATOR 3   =(bpchar, bpchar),
> FUNCTION 1  pg_catalog.text_cmp_bpchar(text, bpchar);

Don't do that.  Btree expects comparison support functions not to leak
memory.  There's zero interest in relaxing that requirement, and also
zero interest in making generic SQL-language functions meet it.

			regards, tom lane