sas=> explain update user set usrid = 'aaaaaaaa' where usrseqid=usrseqid('zlb');
NOTICE: QUERY PLAN:
Seq Scan on user (cost=344.07 size=658 width=154)
EXPLAIN
sas=> explain update user set usrid = 'aaaaaaaa' where usrseqid=(select usrseqid('zlb'));
NOTICE: QUERY PLAN:
Index Scan on user (cost=1.05 size=1 width=154)
InitPlan
-> Result (cost=0.00 size=0 width=0)
EXPLAIN
sas=>
as you can see, it uses the index when the RHS of the comparison in the where
clause is a subquery, but a sequential scan when it isn't. is this a bug?