diff options
| author | Andres Freund <andres@anarazel.de> | 2025-08-11 15:41:34 -0400 |
|---|---|---|
| committer | Andres Freund <andres@anarazel.de> | 2025-08-11 15:41:34 -0400 |
| commit | b227b0bb4e032e19b3679bedac820eba3ac0d1cf (patch) | |
| tree | 16824e186982c38492eba8ca893da21406bdd198 /src | |
| parent | 01d6832c109bcc37acb30e934b7c472334b7c291 (diff) | |
Reduce ExecSeqScan* code size using pg_assume()HEADorigin/masterorigin/HEADmaster
fb9f955025f optimized code generation by using specialized variants of
ExecSeqScan* for [not] having a qual, projection etc. This allowed the
compiler to optimize the code out the code for qual / projection. However, as
observed by David Rowley at the time, the compiler couldn't prove the
opposite, i.e. that the qual etc *are* present.
By using pg_assume(), introduced in d65eb5b1b84, we can tell the compiler that
the relevant variables are non-null.
This reduces the code size to a surprising degree and seems to lead to a small
but reproducible performance gain.
Reviewed-by: Amit Langote <amitlangote09@gmail.com> Discussion:
https://postgr.es/m/CA+HiwqFk-MbwhfX_kucxzL8zLmjEt9MMcHi2YF=DyhPrSjsBEA@mail.gmail.com
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/executor/nodeSeqscan.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/src/backend/executor/nodeSeqscan.c b/src/backend/executor/nodeSeqscan.c index ed35c58c2c3..94047d29430 100644 --- a/src/backend/executor/nodeSeqscan.c +++ b/src/backend/executor/nodeSeqscan.c @@ -131,8 +131,12 @@ ExecSeqScanWithQual(PlanState *pstate) { SeqScanState *node = castNode(SeqScanState, pstate); + /* + * Use pg_assume() for != NULL tests to make the compiler realize no + * runtime check for the field is needed in ExecScanExtended(). + */ Assert(pstate->state->es_epq_active == NULL); - Assert(pstate->qual != NULL); + pg_assume(pstate->qual != NULL); Assert(pstate->ps_ProjInfo == NULL); return ExecScanExtended(&node->ss, @@ -153,7 +157,7 @@ ExecSeqScanWithProject(PlanState *pstate) Assert(pstate->state->es_epq_active == NULL); Assert(pstate->qual == NULL); - Assert(pstate->ps_ProjInfo != NULL); + pg_assume(pstate->ps_ProjInfo != NULL); return ExecScanExtended(&node->ss, (ExecScanAccessMtd) SeqNext, @@ -173,8 +177,8 @@ ExecSeqScanWithQualProject(PlanState *pstate) SeqScanState *node = castNode(SeqScanState, pstate); Assert(pstate->state->es_epq_active == NULL); - Assert(pstate->qual != NULL); - Assert(pstate->ps_ProjInfo != NULL); + pg_assume(pstate->qual != NULL); + pg_assume(pstate->ps_ProjInfo != NULL); return ExecScanExtended(&node->ss, (ExecScanAccessMtd) SeqNext, |