From: Tom Lane <tgl@sss.pgh.pa.us>
To: Etsuro Fujita <etsuro.fujita@gmail.com>
cc: Alexander Lakhin <exclusion@gmail.com>, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #17828: postgres_fdw leaks file descriptors on error and
 aborts aborted transaction in lack of fds
In-reply-to: 
 <CAPmGK15DF6EE7O6hTLbe5-fHvPDwEx9vm-BOCN3dsKOjZCo7bw@mail.gmail.com>
References: <17828-122da8cba23236be@postgresql.org>
 <423731.1678381075@sss.pgh.pa.us>
 <1adf8fee-5a9a-69c2-057a-87bbddebab9d@gmail.com>
 <CAPmGK15anMZdx_nYx8mTY+t0dPJiL3QFot-S4sGm7EJT_WnmhQ@mail.gmail.com>
 <CAPmGK15DF6EE7O6hTLbe5-fHvPDwEx9vm-BOCN3dsKOjZCo7bw@mail.gmail.com>
Comments: In-reply-to Etsuro Fujita <etsuro.fujita@gmail.com>
	message dated "Thu, 08 Feb 2024 21:06:38 +0900"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <974581.1707411864.1@sss.pgh.pa.us>
Date: Thu, 08 Feb 2024 12:04:24 -0500
Message-ID: <974582.1707411864@sss.pgh.pa.us>
Archived-At: 
 <https://www.postgresql.org/message-id/974582.1707411864%40sss.pgh.pa.us>
Precedence: bulk

Etsuro Fujita <etsuro.fujita@gmail.com> writes:
> IIUC I think the assertion failure was caused by an
> error-during-error-recovery loop caused by the "epoll_create1 failed:
> Too many open files" error raised in WaitLatchOrSocket called from
> pgfdw_get_cleanup_result, which is called during abort cleanup.  I
> think a simple fix to avoid such a loop is to modify the PG_CATCH
> block in pgfdw_get_cleanup_result so that it just ignores the passed
> error, not re-throwing it, and restores InterruptHoldoffCount and the
> memory context, like the attached.  In the patch I also modified
> callers of pgfdw_get_cleanup_result to issue a warning when ignoring
> the error.  I might be missing something, though.

I do not think ignoring the passed error is *ever* acceptable.
You have no idea what the error condition is or whether your
hack is sufficient to recover from it.

			regards, tom lane