From: Japin Li <japinli@hotmail.com>
To: "Jack Bonatakis" <jack@bonatak.is>
Cc: pgsql-hackers@lists.postgresql.org
Subject: Re: Fix a server crash problem from pg_get_database_ddl
In-Reply-To: <28b82ab2-5721-4e7c-bf71-979c3f198a2e@app.fastmail.com> (Jack
	Bonatakis's message of "Wed, 15 Apr 2026 20:44:38 -0400")
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On Wed, 15 Apr 2026 at 20:44, "Jack Bonatakis" <jack@bonatak.is> wrote:
> I have reproduced this error against the current master:
>
> ```
> CREATE TABLESPACE ts1 LOCATION '/workspace/tablespaces/pg_bug_ts1';
> CREATE DATABASE db1 TABLESPACE ts1;
> DELETE FROM pg_tablespace WHERE spcname = 'ts1';
> SELECT * FROM pg_get_database_ddl('db1'::regdatabase);
>
> server closed the connection unexpectedly
> This probably means the server terminated abnormally
> before or while processing the request.
> The connection to the server was lost. Attempting reset: Failed.
> ```
> Backend logs show:
>
> ```
> [1] LOG:  client backend (PID 15420) was terminated by signal 11: Segmentation fault
> [1] DETAIL:  Failed process was running: SELECT * FROM pg_get_database_ddl('db1'::regdatabase);
> [1] LOG:  terminating any other active server processes
> ```
> After applying the patch:
>
> ```
> SELECT * FROM pg_get_database_ddl('db1'::regdatabase);
> ERROR:  tablespace with OID 16393 does not exist
> HINT:  To recover, try ALTER DATABASE ... SET TABLESPACE ... to a valid tablespace.
> ```
> and backend logs show:
>
> ```
> [56] ERROR:  tablespace with OID 16393 does not exist
> [56] HINT:  To recover, try ALTER DATABASE ... SET TABLESPACE ... to a valid tablespace.
> [56] STATEMENT:  SELECT * FROM pg_get_database_ddl('db1'::regdatabase);
> ```
> All tests pass.
>
> The only note I'd have on the code change is that there is no accompanying test. It seems like a TAP test would be
> reasonable, but I am quite new and will defer to whether you think that's the right call or even necessary. 
>
> Jack

This seems similar to [1]. Could you please confirm?

[1] https://www.postgresql.org/message-id/CAJTYsWXcd324VELk%3D9KdsfTsua9So3Yexqv7N3B23h9zAUD40g%40mail.gmail.com.

-- 
Regards,
Japin Li
ChengDu WenWu Information Technology Co., Ltd.