On Mon, May 21, 2018 at 4:34 PM, David Rowley
<david.rowley@2ndquadrant.com> wrote:
> On 19 May 2018 at 03:58, Amit Langote <amitlangote09@gmail.com> wrote:
>> I wonder what you think about including this little performance item:
>>
>> https://www.postgresql.org/message-id/E1eotSQ-0005V0-LV@gemulon.postgresql.org
>>
>> especially considering the part of the commit message which states
>>
>> ...Still, testing shows
>> that this makes single-row inserts significantly faster on a table
>> with many partitions without harming the bulk-insert case.
>>
>> I recall seeing those inserts being as much as 2x faster as partition
>> count grows beyond hundreds. One might argue that we should think
>> about publicizing this only after we've dealt with the
>> lock-all-partitions issue that's also mentioned in the commit message
>> which is still a significant portion of the time spent and I'm totally
>> fine with that.
>
> While I do think that was a good change, I do think there's much still
> left to do to speed up usage of partitioned tables with many
> partitions.
>
> I've been working a bit in this area over the past few weeks and with
> PG11 I measured a single INSERT into a 10k RANGE partitioned table at
> just 84 tps (!), while inserting the same row into a non-partitioned
> table was about 11.1k tps. I have patches locally that take this up to
> ~9.8k tps, which I'll submit for PG12. I'm unsure if we should be
> shouting anything from the rooftops about the work done in this area
> for PG11, since it's still got a long way to go still before the
> feature is usable with higher numbers of partitions. I do think your
> change was a good one to make, but I just don't want users to think
> that we're done here when we all know that much work remains.
>
> If we're going to add an item in the release notes about this then I
> wouldn't object, providing it could be done in a way that indicates
> we've not finished here yet, but if that's the case then maybe it's
> better to say nothing at all.
You're right, it surely isn't time yet to make fanfare about this. I
will look forward to being able to review your patches. :-)
Thanks,
Amit
