Hello, please look into following example:
postgres=# create table test_array_selectivity as select
array[id]::int[] as a from generate_series(1, 1000) gs(id);
SELECT 1000
postgres=# explain analyze select * from test_array_selectivity where a
@> array[1];
On Sat, May 28, 2022 at 01:40:14AM +0800, 徐志宇徐 wrote:
> vm.swappiness=0
I think this is related to the problem.
swappiness=0 means to *never* use swap, even if that means that processes are
killed.
If you really wanted that, you should remove the swap space.
Swap is extremely slow and worth avo
Alexey Ermakov writes:
> so if we store mostly one element in array and they're almost all
> distinct then in tables with more then stats_target/0.0063 (~1.58M for
> maximum stats target 1) rows we'll get 0.005 constant for selectivity.
Yeah. There's a comment in array_selfuncs.c about
*
