From: Tom Lane <tgl@sss.pgh.pa.us>
To: linwenbo1994@gmail.com
cc: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #17883: Segmentation fault when create brin index on
 user-defined type.
In-reply-to: <17883-7bb64f11e60bc1ef@postgresql.org>
References: <17883-7bb64f11e60bc1ef@postgresql.org>
Comments: In-reply-to PG Bug reporting form <noreply@postgresql.org>
	message dated "Tue, 04 Apr 2023 05:51:56 -0000"
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Date: Tue, 04 Apr 2023 08:38:22 -0400
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PG Bug reporting form <noreply@postgresql.org> writes:
> CREATE OPERATOR CLASS sva_special_ops
> FOR TYPE text using brin
> AS
>     OPERATOR 1 <#,
>     OPERATOR 2 <=#,
>     OPERATOR 3 >=#,
>     OPERATOR 4 >#,
> function 1 si_same(text,text);

This is certainly not a valid BRIN operator class definition.
There are four required support functions, not just one, and
I seriously doubt that any of them can usefully be written in
plpgsql.  (You also got the set of operators wrong, but that's
not the issue here.)  See

https://www.postgresql.org/docs/current/brin-extensibility.html

And yes, invalid operator class definitions can crash the system.
That's why you can't create one unless you're superuser.

			regards, tom lane