Re: speeding up planning with partitions

On 2019/03/25 20:34, Amit Langote wrote:
> Performance loss for smaller number of partitions is in the noise range,
> but what we gain for large number of partitions seems pretty significant
> to me:

I didn't specify the benchmark setup instructions:

partitioned table creation (N: 2...8192):

create table rt (a int, b int, c int) partition by range (a);
select 'create table rt' || x::text || ' partition of rt for values from
(' || (x)::text || ') to (' || (x+1)::text || ');' from generate_series(1,
N) x;
\gexec

select.sql:

\set param random(1, N)
select * from rt where a = :param;

pgbench -n -T 120 -f select.sql

> nparts no live_parts live_parts
> ====== ============= ==========
> 2 3397 3391
> 8 3365 3337
> 32 3316 3379
> 128 3338 3399
> 512 3273 3321
> 1024 3439 3517
> 4096 3113 3227
> 8192 2849 3215
>
> Attached find updated patches.

Rebased patches attached.

Thanks,
Amit