Hi,
On 3/19/19 11:15 PM, Imai, Yoshikazu wrote:
Here the details.
[creating partitioned tables (with 1024 partitions)]
drop table if exists rt;
create table rt (a int, b int, c int) partition by range (a);
\o /dev/null
select 'create table rt' || x::text || ' partition of rt for values from (' ||
(x)::text || ') to (' || (x+1)::text || ');' from generate_series(1, 1024) x;
\gexec
\o
[select1024.sql]
\set a random (1, 1024)
select * from rt where a = :a;
[pgbench]
pgbench -n -f select1024.sql -T 60
My tests - using hash partitions - shows that the extra time is spent in
make_partition_pruneinfo() for the relid_subplan_map variable.
64 partitions: make_partition_pruneinfo() 2.52%
8192 partitions: make_partition_pruneinfo() 5.43%
TPS goes down ~8% between the two. The test setup is similar to the above.
Given that Tom is planning to change the List implementation [1] in 13 I
think using the palloc0 structure is ok for 12 before trying other
implementation options.
perf sent off-list.
[1] https://www.postgresql.org/message-id/24783.1551568303%40sss.pgh.pa.us
Best regards,
Jesper
