Inanc Seylan <inanc.seylan@gmail.com> writes:
> It is IMMUTABLE. I attach the output of EXPLAIN both with and without
> the simple function (returning true only) in the query.
EXPLAIN ANALYZE would have been far more helpful. However, the thing
that jumps out at me here is all the seqscans on table "symbols".
Do you not have an index on symbols.id? If you do, perhaps there is
a datatype-mismatch problem preventing it from being used.
regards, tom lane