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[PATCH v3 3/6] Convert ParallelBitmapHeapState->state to an atomic variable. 1+ messages / 1 participants [nested] [flat]
* [PATCH v3 3/6] Convert ParallelBitmapHeapState->state to an atomic variable. @ 2026-09-08 17:40 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 1+ messages in thread From: Nathan Bossart @ 2026-09-08 17:40 UTC (permalink / raw) Currently, this variable is a SharedBitmapState protected by a spinlock. By converting it to an atomic variable, we can remove the spinlock. --- src/backend/executor/nodeBitmapHeapscan.c | 23 +++++++---------------- 1 file changed, 7 insertions(+), 16 deletions(-) diff --git a/src/backend/executor/nodeBitmapHeapscan.c b/src/backend/executor/nodeBitmapHeapscan.c index 83d6478bc2b..a9e83f30687 100644 --- a/src/backend/executor/nodeBitmapHeapscan.c +++ b/src/backend/executor/nodeBitmapHeapscan.c @@ -79,7 +79,6 @@ typedef enum /* ---------------- * ParallelBitmapHeapState information * tbmiterator iterator for scanning current pages - * mutex mutual exclusion for state * state current state of the TIDBitmap * cv conditional wait variable * ---------------- @@ -87,8 +86,7 @@ typedef enum typedef struct ParallelBitmapHeapState { dsa_pointer tbmiterator; - slock_t mutex; - SharedBitmapState state; + pg_atomic_uint32 state; ConditionVariable cv; } ParallelBitmapHeapState; @@ -228,9 +226,7 @@ BitmapHeapNext(BitmapHeapScanState *node) static inline void BitmapDoneInitializingSharedState(ParallelBitmapHeapState *pstate) { - SpinLockAcquire(&pstate->mutex); - pstate->state = BM_FINISHED; - SpinLockRelease(&pstate->mutex); + pg_atomic_write_membarrier_u32(&pstate->state, BM_FINISHED); ConditionVariableBroadcast(&pstate->cv); } @@ -476,15 +472,12 @@ ExecInitBitmapHeapScan(BitmapHeapScan *node, EState *estate, int eflags) static bool BitmapShouldInitializeSharedState(ParallelBitmapHeapState *pstate) { - SharedBitmapState state; + uint32 state; while (1) { - SpinLockAcquire(&pstate->mutex); - state = pstate->state; - if (pstate->state == BM_INITIAL) - pstate->state = BM_INPROGRESS; - SpinLockRelease(&pstate->mutex); + state = BM_INITIAL; + pg_atomic_compare_exchange_u32(&pstate->state, &state, BM_INPROGRESS); /* Exit if bitmap is done, or if we're the leader. */ if (state != BM_INPROGRESS) @@ -538,9 +531,7 @@ ExecBitmapHeapInitializeDSM(BitmapHeapScanState *node, pstate->tbmiterator = 0; - /* Initialize the mutex */ - SpinLockInit(&pstate->mutex); - pstate->state = BM_INITIAL; + pg_atomic_init_u32(&pstate->state, BM_INITIAL); ConditionVariableInit(&pstate->cv); @@ -565,7 +556,7 @@ ExecBitmapHeapReInitializeDSM(BitmapHeapScanState *node, if (dsa == NULL) return; - pstate->state = BM_INITIAL; + pg_atomic_write_u32(&pstate->state, BM_INITIAL); if (DsaPointerIsValid(pstate->tbmiterator)) tbm_free_shared_area(dsa, pstate->tbmiterator); -- 2.55.0 --hwKv7DgSDwjNaYBK Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename=v3-0004-Convert-PROC_HDR-startupBufferPinWaitBuf-to-an-at.patch ^ permalink raw reply [nested|flat] 1+ messages in thread
only message in thread Thread overview: 1+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2026-09-08 17:40 [PATCH v3 3/6] Convert ParallelBitmapHeapState->state to an atomic variable. Nathan Bossart <nathan@postgresql.org>
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