Re: Optimizing FastPathTransferRelationLocks()

On 2025/03/11 20:55, Ashutosh Bapat wrote:
> Hi Fujii-san,
> 
> It seems that this was forgotten somehow.
> 
> The patch still applies.
> 
> Examining c4d5cb71d229095a39fda1121a75ee40e6069a2a, it seems that this patch
> could have been part of that commit as well. But may be it wasn't so apparent
> that time. I think it's a good improvement.

Thanks for reviewing the patch!


> On Tue, Nov 19, 2024 at 10:14 PM Fujii Masao
> <masao.fujii@oss.nttdata.com> wrote:
>>
>> The latest version of the patch is attached.
> 
> @@ -2773,6 +2773,10 @@ FastPathTransferRelationLocks(LockMethod
> lockMethodTable, const LOCKTAG *locktag
> LWLock *partitionLock = LockHashPartitionLock(hashcode);
> Oid relid = locktag->locktag_field2;
> uint32 i;
> + uint32 group;
> +
> + /* fast-path group the lock belongs to */
> + group = FAST_PATH_REL_GROUP(relid);
> 
> We could just combine variable declaration and initialization; similar
> to partitionLock.

I’ve updated the patch as suggested. Updated patch is attached.


> The performance gain from this patch might be tiny and may not be
> visible. Still, have you tried to measure the performance improvement?

I haven’t measured the actual performance gain since the patch optimizes
the logic in a clear and logical way. While we might see some improvement
in artificial scenarios — like with a large max_connections and
all backends slots having their databaseIds set, I’m not sure
how meaningful that would be.

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION