On Thu, 12 Oct 2023 at 23:06, Ashutosh Bapat <ashutosh.bapat....@gmail.com> wrote: > Q7 select distinct a,b from (select string_agg(left(a, 100), ', ') > over (order by a rows 2 preceding) a, b from t_text) q > HEAD: 16070.62 ms > patched: 16182.16 ms
Did you time the SELECT or EXPLAIN ANALYZE? With SELECT, I'm unable to recreate this slowdown. Using your setup: $ cat bench.sql set enable_hashagg=0; set work_mem='10GB'; select distinct a,b from (select string_agg(left(a, 100), ', ') over (order by a rows 2 preceding) a, b from t_text) q; Master @ 13d00729d $ pgbench -n -f bench.sql -T 300 postgres | grep latency latency average = 7739.250 ms Master + use_subnode_slot_type_for_nodeunique.patch $ pgbench -n -f bench.sql -T 300 postgres | grep latency latency average = 7718.007 ms It's hard to imagine why there would be a slowdown as this query uses a TTSOpsMinimalTuple slot type in the patch and the unpatched version. David
