Horton

Re: memory leak in trigger handling (since PG12)

Tomas Vondra <tomas.vondra@enterprisedb.com>

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From: Tomas Vondra <tomas.vondra@enterprisedb.com>
To: Andres Freund <andres@anarazel.de>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2023-05-25T14:43:55Z
Lists: pgsql-hackers 
On 5/24/23 22:19, Andres Freund wrote:
>
> ...
> 
> Hm - stepping back a bit, why are we doing the work in ExecGetAllUpdatedCols()
> over and over?  Unless I am missing something, the result doesn't change
> across rows. And it doesn't look that cheap to compute, leaving aside the
> allocation that bms_union() does.
> 
> It's visible in profiles, not as a top entry, but still.
> 
> Perhaps the easiest to backpatch fix is to just avoid recomputing the value?
> But perhaps it'd be just as problmeatic, because callers might modify
> ExecGetAllUpdatedCols()'s return value in place...
> 

Yes, I think that's a perfectly valid point - I was actually wondering
about that too, but I was focused on fixing this in backbranches so I
left this as a future optimization (assuming it can be cached).


regards

-- 
Tomas Vondra
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

  1. Fix oversight in handling of modifiedCols since f24523672d

  2. Use per-tuple context in ExecGetAllUpdatedCols

  3. Generated columns