diff options
Diffstat (limited to 'src/backend/executor/nodeIndexscan.c')
| -rw-r--r-- | src/backend/executor/nodeIndexscan.c | 153 |
1 files changed, 137 insertions, 16 deletions
diff --git a/src/backend/executor/nodeIndexscan.c b/src/backend/executor/nodeIndexscan.c index 5734550d2c7..0a9dfdbaf30 100644 --- a/src/backend/executor/nodeIndexscan.c +++ b/src/backend/executor/nodeIndexscan.c @@ -22,6 +22,9 @@ * ExecEndIndexScan releases all storage. * ExecIndexMarkPos marks scan position. * ExecIndexRestrPos restores scan position. + * ExecIndexScanEstimate estimates DSM space needed for parallel index scan + * ExecIndexScanInitializeDSM initialize DSM for parallel indexscan + * ExecIndexScanInitializeWorker attach to DSM info in parallel worker */ #include "postgres.h" @@ -514,6 +517,18 @@ ExecIndexScan(IndexScanState *node) void ExecReScanIndexScan(IndexScanState *node) { + bool reset_parallel_scan = true; + + /* + * If we are here to just update the scan keys, then don't reset parallel + * scan. We don't want each of the participating process in the parallel + * scan to update the shared parallel scan state at the start of the scan. + * It is quite possible that one of the participants has already begun + * scanning the index when another has yet to start it. + */ + if (node->iss_NumRuntimeKeys != 0 && !node->iss_RuntimeKeysReady) + reset_parallel_scan = false; + /* * If we are doing runtime key calculations (ie, any of the index key * values weren't simple Consts), compute the new key values. But first, @@ -539,10 +554,21 @@ ExecReScanIndexScan(IndexScanState *node) reorderqueue_pop(node); } - /* reset index scan */ - index_rescan(node->iss_ScanDesc, - node->iss_ScanKeys, node->iss_NumScanKeys, - node->iss_OrderByKeys, node->iss_NumOrderByKeys); + /* + * Reset (parallel) index scan. For parallel-aware nodes, the scan + * descriptor is initialized during actual execution of node and we can + * reach here before that (ex. during execution of nest loop join). So, + * avoid updating the scan descriptor at that time. + */ + if (node->iss_ScanDesc) + { + index_rescan(node->iss_ScanDesc, + node->iss_ScanKeys, node->iss_NumScanKeys, + node->iss_OrderByKeys, node->iss_NumOrderByKeys); + + if (reset_parallel_scan && node->iss_ScanDesc->parallel_scan) + index_parallelrescan(node->iss_ScanDesc); + } node->iss_ReachedEnd = false; ExecScanReScan(&node->ss); @@ -1013,22 +1039,29 @@ ExecInitIndexScan(IndexScan *node, EState *estate, int eflags) } /* - * Initialize scan descriptor. + * for parallel-aware node, we initialize the scan descriptor after + * initializing the shared memory for parallel execution. */ - indexstate->iss_ScanDesc = index_beginscan(currentRelation, - indexstate->iss_RelationDesc, - estate->es_snapshot, - indexstate->iss_NumScanKeys, + if (!node->scan.plan.parallel_aware) + { + /* + * Initialize scan descriptor. + */ + indexstate->iss_ScanDesc = index_beginscan(currentRelation, + indexstate->iss_RelationDesc, + estate->es_snapshot, + indexstate->iss_NumScanKeys, indexstate->iss_NumOrderByKeys); - /* - * If no run-time keys to calculate, go ahead and pass the scankeys to the - * index AM. - */ - if (indexstate->iss_NumRuntimeKeys == 0) - index_rescan(indexstate->iss_ScanDesc, - indexstate->iss_ScanKeys, indexstate->iss_NumScanKeys, + /* + * If no run-time keys to calculate, go ahead and pass the scankeys to + * the index AM. + */ + if (indexstate->iss_NumRuntimeKeys == 0) + index_rescan(indexstate->iss_ScanDesc, + indexstate->iss_ScanKeys, indexstate->iss_NumScanKeys, indexstate->iss_OrderByKeys, indexstate->iss_NumOrderByKeys); + } /* * all done. @@ -1590,3 +1623,91 @@ ExecIndexBuildScanKeys(PlanState *planstate, Relation index, else if (n_array_keys != 0) elog(ERROR, "ScalarArrayOpExpr index qual found where not allowed"); } + +/* ---------------------------------------------------------------- + * Parallel Scan Support + * ---------------------------------------------------------------- + */ + +/* ---------------------------------------------------------------- + * ExecIndexScanEstimate + * + * estimates the space required to serialize indexscan node. + * ---------------------------------------------------------------- + */ +void +ExecIndexScanEstimate(IndexScanState *node, + ParallelContext *pcxt) +{ + EState *estate = node->ss.ps.state; + + node->iss_PscanLen = index_parallelscan_estimate(node->iss_RelationDesc, + estate->es_snapshot); + shm_toc_estimate_chunk(&pcxt->estimator, node->iss_PscanLen); + shm_toc_estimate_keys(&pcxt->estimator, 1); +} + +/* ---------------------------------------------------------------- + * ExecIndexScanInitializeDSM + * + * Set up a parallel index scan descriptor. + * ---------------------------------------------------------------- + */ +void +ExecIndexScanInitializeDSM(IndexScanState *node, + ParallelContext *pcxt) +{ + EState *estate = node->ss.ps.state; + ParallelIndexScanDesc piscan; + + piscan = shm_toc_allocate(pcxt->toc, node->iss_PscanLen); + index_parallelscan_initialize(node->ss.ss_currentRelation, + node->iss_RelationDesc, + estate->es_snapshot, + piscan); + shm_toc_insert(pcxt->toc, node->ss.ps.plan->plan_node_id, piscan); + node->iss_ScanDesc = + index_beginscan_parallel(node->ss.ss_currentRelation, + node->iss_RelationDesc, + node->iss_NumScanKeys, + node->iss_NumOrderByKeys, + piscan); + + /* + * If no run-time keys to calculate, go ahead and pass the scankeys to the + * index AM. + */ + if (node->iss_NumRuntimeKeys == 0) + index_rescan(node->iss_ScanDesc, + node->iss_ScanKeys, node->iss_NumScanKeys, + node->iss_OrderByKeys, node->iss_NumOrderByKeys); +} + +/* ---------------------------------------------------------------- + * ExecIndexScanInitializeWorker + * + * Copy relevant information from TOC into planstate. + * ---------------------------------------------------------------- + */ +void +ExecIndexScanInitializeWorker(IndexScanState *node, shm_toc *toc) +{ + ParallelIndexScanDesc piscan; + + piscan = shm_toc_lookup(toc, node->ss.ps.plan->plan_node_id); + node->iss_ScanDesc = + index_beginscan_parallel(node->ss.ss_currentRelation, + node->iss_RelationDesc, + node->iss_NumScanKeys, + node->iss_NumOrderByKeys, + piscan); + + /* + * If no run-time keys to calculate, go ahead and pass the scankeys to the + * index AM. + */ + if (node->iss_NumRuntimeKeys == 0) + index_rescan(node->iss_ScanDesc, + node->iss_ScanKeys, node->iss_NumScanKeys, + node->iss_OrderByKeys, node->iss_NumOrderByKeys); +} |