From 6a570e087696479f1be020c13891c8c6242d91e7 Mon Sep 17 00:00:00 2001 From: Tomas Vondra Date: Fri, 3 Apr 2026 14:15:28 +0200 Subject: [PATCH v8 2/5] Show Bitmap Heap Scan stats for non-parallel-aware workers Commit 5a1e6df3b84c added information about exact/lossy pages for each parallel worker. It however works only for parallel-aware scans, not for other parallel scans. For example scans on the outer side of a parallel join are not parallel-aware, and so won't report the stats. Similarly, queries run with debug_parallel_query=regress are not parallel-aware, which may cause regression failures due to changes in explain output. Fixed in a way similar to 0fbceae841cb, by invoking functions always, and only then considering parallel_aware. Probably needs to be backpatched to 18. --- src/backend/commands/explain.c | 2 +- src/backend/executor/execParallel.c | 18 ++--- src/backend/executor/nodeBitmapHeapscan.c | 86 ++++++++++++++++------- 3 files changed, 71 insertions(+), 35 deletions(-) diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c index e4b70166b0e..8275bb2af61 100644 --- a/src/backend/commands/explain.c +++ b/src/backend/commands/explain.c @@ -3949,7 +3949,7 @@ show_tidbitmap_info(BitmapHeapScanState *planstate, ExplainState *es) } /* Display stats for each parallel worker */ - if (planstate->pstate != NULL) + if (planstate->sinstrument != NULL) { for (int n = 0; n < planstate->sinstrument->num_workers; n++) { diff --git a/src/backend/executor/execParallel.c b/src/backend/executor/execParallel.c index 755191b51ef..ce377a774f8 100644 --- a/src/backend/executor/execParallel.c +++ b/src/backend/executor/execParallel.c @@ -290,9 +290,9 @@ ExecParallelEstimate(PlanState *planstate, ExecParallelEstimateContext *e) e->pcxt); break; case T_BitmapHeapScanState: - if (planstate->plan->parallel_aware) - ExecBitmapHeapEstimate((BitmapHeapScanState *) planstate, - e->pcxt); + /* even when not parallel-aware, for EXPLAIN ANALYZE */ + ExecBitmapHeapEstimate((BitmapHeapScanState *) planstate, + e->pcxt); break; case T_HashJoinState: if (planstate->plan->parallel_aware) @@ -522,9 +522,9 @@ ExecParallelInitializeDSM(PlanState *planstate, d->pcxt); break; case T_BitmapHeapScanState: - if (planstate->plan->parallel_aware) - ExecBitmapHeapInitializeDSM((BitmapHeapScanState *) planstate, - d->pcxt); + /* even when not parallel-aware, for EXPLAIN ANALYZE */ + ExecBitmapHeapInitializeDSM((BitmapHeapScanState *) planstate, + d->pcxt); break; case T_HashJoinState: if (planstate->plan->parallel_aware) @@ -1400,9 +1400,9 @@ ExecParallelInitializeWorker(PlanState *planstate, ParallelWorkerContext *pwcxt) pwcxt); break; case T_BitmapHeapScanState: - if (planstate->plan->parallel_aware) - ExecBitmapHeapInitializeWorker((BitmapHeapScanState *) planstate, - pwcxt); + /* even when not parallel-aware, for EXPLAIN ANALYZE */ + ExecBitmapHeapInitializeWorker((BitmapHeapScanState *) planstate, + pwcxt); break; case T_HashJoinState: if (planstate->plan->parallel_aware) diff --git a/src/backend/executor/nodeBitmapHeapscan.c b/src/backend/executor/nodeBitmapHeapscan.c index 73831aed451..0c580365e9c 100644 --- a/src/backend/executor/nodeBitmapHeapscan.c +++ b/src/backend/executor/nodeBitmapHeapscan.c @@ -495,9 +495,21 @@ void ExecBitmapHeapEstimate(BitmapHeapScanState *node, ParallelContext *pcxt) { - Size size; + Size size = 0; + bool instrument = (node->ss.ps.instrument != NULL); + bool parallel_aware = node->ss.ps.plan->parallel_aware; - size = MAXALIGN(sizeof(ParallelBitmapHeapState)); + if (!instrument && !parallel_aware) + { + /* No DSM required by the scan */ + return; + } + + /* parallel state is needed only in parallel-aware scans */ + if (parallel_aware) + { + size = MAXALIGN(sizeof(ParallelBitmapHeapState)); + } /* account for instrumentation, if required */ if (node->ss.ps.instrument && pcxt->nworkers > 0) @@ -521,48 +533,61 @@ ExecBitmapHeapInitializeDSM(BitmapHeapScanState *node, ParallelContext *pcxt) { ParallelBitmapHeapState *pstate; + bool instrument = node->ss.ps.instrument != NULL; + bool parallel_aware = node->ss.ps.plan->parallel_aware; SharedBitmapHeapInstrumentation *sinstrument = NULL; - dsa_area *dsa = node->ss.ps.state->es_query_dsa; char *ptr; - Size size; + Size size = 0; - /* If there's no DSA, there are no workers; initialize nothing. */ - if (dsa == NULL) + if (!instrument && !parallel_aware) + { + /* No DSM required by the scan */ return; + } - size = MAXALIGN(sizeof(ParallelBitmapHeapState)); - if (node->ss.ps.instrument && pcxt->nworkers > 0) + /* parallel state is needed only in parallel-aware scans */ + if (parallel_aware) + { + size = MAXALIGN(sizeof(ParallelBitmapHeapState)); + } + + if (instrument && pcxt->nworkers > 0) { size = add_size(size, offsetof(SharedBitmapHeapInstrumentation, sinstrument)); size = add_size(size, mul_size(pcxt->nworkers, sizeof(BitmapHeapScanInstrumentation))); } ptr = shm_toc_allocate(pcxt->toc, size); - pstate = (ParallelBitmapHeapState *) ptr; - ptr += MAXALIGN(sizeof(ParallelBitmapHeapState)); - if (node->ss.ps.instrument && pcxt->nworkers > 0) - sinstrument = (SharedBitmapHeapInstrumentation *) ptr; + shm_toc_insert(pcxt->toc, node->ss.ps.plan->plan_node_id, ptr); + + if (parallel_aware) + { + pstate = (ParallelBitmapHeapState *) ptr; + ptr += MAXALIGN(sizeof(ParallelBitmapHeapState)); - pstate->tbmiterator = 0; + pstate->tbmiterator = 0; - /* Initialize the mutex */ - SpinLockInit(&pstate->mutex); - pstate->state = BM_INITIAL; + /* Initialize the mutex */ + SpinLockInit(&pstate->mutex); + pstate->state = BM_INITIAL; - ConditionVariableInit(&pstate->cv); + ConditionVariableInit(&pstate->cv); - if (sinstrument) + node->pstate = pstate; + } + + if (instrument && pcxt->nworkers > 0) { + sinstrument = (SharedBitmapHeapInstrumentation *) ptr; + sinstrument->num_workers = pcxt->nworkers; /* ensure any unfilled slots will contain zeroes */ memset(sinstrument->sinstrument, 0, pcxt->nworkers * sizeof(BitmapHeapScanInstrumentation)); - } - shm_toc_insert(pcxt->toc, node->ss.ps.plan->plan_node_id, pstate); - node->pstate = pstate; - node->sinstrument = sinstrument; + node->sinstrument = sinstrument; + } } /* ---------------------------------------------------------------- @@ -600,16 +625,27 @@ void ExecBitmapHeapInitializeWorker(BitmapHeapScanState *node, ParallelWorkerContext *pwcxt) { + bool instrument = node->ss.ps.instrument != NULL; + bool parallel_aware = node->ss.ps.plan->parallel_aware; char *ptr; + if (!instrument && !parallel_aware) + { + /* No DSM required by the scan */ + return; + } + Assert(node->ss.ps.state->es_query_dsa != NULL); ptr = shm_toc_lookup(pwcxt->toc, node->ss.ps.plan->plan_node_id, false); - node->pstate = (ParallelBitmapHeapState *) ptr; - ptr += MAXALIGN(sizeof(ParallelBitmapHeapState)); + if (parallel_aware) + { + node->pstate = (ParallelBitmapHeapState *) ptr; + ptr += MAXALIGN(sizeof(ParallelBitmapHeapState)); + } - if (node->ss.ps.instrument) + if (instrument) node->sinstrument = (SharedBitmapHeapInstrumentation *) ptr; } -- 2.53.0