Thread: pgsql: Speedup Hash Joins with dedicated functions for ExprState hashin
Speedup Hash Joins with dedicated functions for ExprState hashing Hashing of a single Var is a very common operation for ExprState to perform. Here we add dedicated ExecJust* functions which helps speed up Hash Joins by removing the interpretation overhead in ExecInterpExpr(). This change currently only affects Hash Joins on a single column. Hash Joins with multiple join keys or an expression still run through ExecInterpExpr(). Some testing has shown up to 10% query performance increases on recent AMD hardware and nearly 7% increase on an Apple M2 for a query performing a hash join with a large number of lookups on a small hash table. This change was extracted from a larger patch which adjusts GROUP BY / hashed subplans / hashed set operations to use ExprState hashing. Discussion: https://postgr.es/m/CAApHDvr8Zc0ZgzVoCZLdHGOFNhiJeQ6vrUcS9V7N23zMWQb-eA@mail.gmail.com Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/50416cc4843a85fcb53507e21577cce16c75c65f Modified Files -------------- src/backend/executor/execExprInterp.c | 206 +++++++++++++++++++++++++++++++++- 1 file changed, 205 insertions(+), 1 deletion(-)