On 2018-Oct-11, Tom Lane wrote: > I have been fooling around with a patch to allow pull-up of sub-selects > that lack any FROM, along the lines discussed in > https://www.postgresql.org/message-id/15944.1521127...@sss.pgh.pa.us > I find that it is smart enough to reduce that EXISTS to a plain > expression, yielding > > QUERY PLAN > ---------------------------------------------------- > Subquery Scan on tenk1_vw_sec > -> Index Only Scan using tenk1_unique1 on tenk1 > Index Cond: (unique1 = 0) > (3 rows)
Hmm, I have the feeling that this would nullify some tests in partition_prune also, which IIRC pretend to invoke runtime pruning with things like "WHERE partcol = (select 1)". -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
