Re: dshash_find_or_insert vs. OOM

Robert Haas <robertmhaas@gmail.com>

From: Robert Haas <robertmhaas@gmail.com>
To: Chao Li <li.evan.chao@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Andres Freund <andres@anarazel.de>, Thomas Munro <thomas.munro@gmail.com>
Date: 2026-03-18T17:46:14Z
Lists: pgsql-hackers

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On Tue, Mar 17, 2026 at 9:34 PM Chao Li <li.evan.chao@gmail.com> wrote:
> When OOM happens, Assert((flags & DSHASH_INSERT_NO_OOM) != 0); makes sense. But for resize(), the assert is inside resize(), while for insert_into_bucket(), the assert is in the caller. That feels a bit inconsistent to me, and I think it hurts readability a little. A reader might wonder why there is no corresponding assert after resize() unless they go read the function body.

Adjusted.

> Making this a nested block does have the benefit of keeping dsa_flags close to where it is used. But from my impression, this style is still fairly uncommon in the codebase. I worry it may implicitly signal to other hackers that this is an acceptable pattern. So unless we intentionally want to encourage that style, I would lean toward avoiding it here.

Yeah, that was dumb. Fixed.

Thanks for the review; here's v2.

-- 
Robert Haas
EDB: http://www.enterprisedb.com

Commits

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  1. dshash: Make it possible to suppress out of memory errors