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-rw-r--r--src/backend/executor/Makefile2
-rw-r--r--src/backend/executor/execAmi.c8
-rw-r--r--src/backend/executor/execCurrent.c1
-rw-r--r--src/backend/executor/execProcnode.c14
-rw-r--r--src/backend/executor/nodeSamplescan.c256
5 files changed, 280 insertions, 1 deletions
diff --git a/src/backend/executor/Makefile b/src/backend/executor/Makefile
index bc5d373d68a..08cba6fa2b5 100644
--- a/src/backend/executor/Makefile
+++ b/src/backend/executor/Makefile
@@ -21,7 +21,7 @@ OBJS = execAmi.o execCurrent.o execGrouping.o execIndexing.o execJunk.o \
nodeLimit.o nodeLockRows.o \
nodeMaterial.o nodeMergeAppend.o nodeMergejoin.o nodeModifyTable.o \
nodeNestloop.o nodeFunctionscan.o nodeRecursiveunion.o nodeResult.o \
- nodeSeqscan.o nodeSetOp.o nodeSort.o nodeUnique.o \
+ nodeSamplescan.o nodeSeqscan.o nodeSetOp.o nodeSort.o nodeUnique.o \
nodeValuesscan.o nodeCtescan.o nodeWorktablescan.o \
nodeGroup.o nodeSubplan.o nodeSubqueryscan.o nodeTidscan.o \
nodeForeignscan.o nodeWindowAgg.o tstoreReceiver.o spi.o
diff --git a/src/backend/executor/execAmi.c b/src/backend/executor/execAmi.c
index 6ebad2f03f0..4948a265cb2 100644
--- a/src/backend/executor/execAmi.c
+++ b/src/backend/executor/execAmi.c
@@ -39,6 +39,7 @@
#include "executor/nodeNestloop.h"
#include "executor/nodeRecursiveunion.h"
#include "executor/nodeResult.h"
+#include "executor/nodeSamplescan.h"
#include "executor/nodeSeqscan.h"
#include "executor/nodeSetOp.h"
#include "executor/nodeSort.h"
@@ -155,6 +156,10 @@ ExecReScan(PlanState *node)
ExecReScanSeqScan((SeqScanState *) node);
break;
+ case T_SampleScanState:
+ ExecReScanSampleScan((SampleScanState *) node);
+ break;
+
case T_IndexScanState:
ExecReScanIndexScan((IndexScanState *) node);
break;
@@ -480,6 +485,9 @@ ExecSupportsBackwardScan(Plan *node)
}
return false;
+ case T_SampleScan:
+ return false;
+
case T_Material:
case T_Sort:
/* these don't evaluate tlist */
diff --git a/src/backend/executor/execCurrent.c b/src/backend/executor/execCurrent.c
index d87be963a95..bcd287f8742 100644
--- a/src/backend/executor/execCurrent.c
+++ b/src/backend/executor/execCurrent.c
@@ -261,6 +261,7 @@ search_plan_tree(PlanState *node, Oid table_oid)
* Relation scan nodes can all be treated alike
*/
case T_SeqScanState:
+ case T_SampleScanState:
case T_IndexScanState:
case T_IndexOnlyScanState:
case T_BitmapHeapScanState:
diff --git a/src/backend/executor/execProcnode.c b/src/backend/executor/execProcnode.c
index 9892499fb7a..03c2febc3e1 100644
--- a/src/backend/executor/execProcnode.c
+++ b/src/backend/executor/execProcnode.c
@@ -102,6 +102,7 @@
#include "executor/nodeNestloop.h"
#include "executor/nodeRecursiveunion.h"
#include "executor/nodeResult.h"
+#include "executor/nodeSamplescan.h"
#include "executor/nodeSeqscan.h"
#include "executor/nodeSetOp.h"
#include "executor/nodeSort.h"
@@ -190,6 +191,11 @@ ExecInitNode(Plan *node, EState *estate, int eflags)
estate, eflags);
break;
+ case T_SampleScan:
+ result = (PlanState *) ExecInitSampleScan((SampleScan *) node,
+ estate, eflags);
+ break;
+
case T_IndexScan:
result = (PlanState *) ExecInitIndexScan((IndexScan *) node,
estate, eflags);
@@ -406,6 +412,10 @@ ExecProcNode(PlanState *node)
result = ExecSeqScan((SeqScanState *) node);
break;
+ case T_SampleScanState:
+ result = ExecSampleScan((SampleScanState *) node);
+ break;
+
case T_IndexScanState:
result = ExecIndexScan((IndexScanState *) node);
break;
@@ -644,6 +654,10 @@ ExecEndNode(PlanState *node)
ExecEndSeqScan((SeqScanState *) node);
break;
+ case T_SampleScanState:
+ ExecEndSampleScan((SampleScanState *) node);
+ break;
+
case T_IndexScanState:
ExecEndIndexScan((IndexScanState *) node);
break;
diff --git a/src/backend/executor/nodeSamplescan.c b/src/backend/executor/nodeSamplescan.c
new file mode 100644
index 00000000000..fc89d1dca03
--- /dev/null
+++ b/src/backend/executor/nodeSamplescan.c
@@ -0,0 +1,256 @@
+/*-------------------------------------------------------------------------
+ *
+ * nodeSamplescan.c
+ * Support routines for sample scans of relations (table sampling).
+ *
+ * Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ * src/backend/executor/nodeSamplescan.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "access/tablesample.h"
+#include "executor/executor.h"
+#include "executor/nodeSamplescan.h"
+#include "miscadmin.h"
+#include "parser/parsetree.h"
+#include "pgstat.h"
+#include "storage/bufmgr.h"
+#include "storage/predicate.h"
+#include "utils/rel.h"
+#include "utils/syscache.h"
+#include "utils/tqual.h"
+
+static void InitScanRelation(SampleScanState *node, EState *estate,
+ int eflags, TableSampleClause *tablesample);
+static TupleTableSlot *SampleNext(SampleScanState *node);
+
+
+/* ----------------------------------------------------------------
+ * Scan Support
+ * ----------------------------------------------------------------
+ */
+
+/* ----------------------------------------------------------------
+ * SampleNext
+ *
+ * This is a workhorse for ExecSampleScan
+ * ----------------------------------------------------------------
+ */
+static TupleTableSlot *
+SampleNext(SampleScanState *node)
+{
+ TupleTableSlot *slot;
+ TableSampleDesc *tsdesc;
+ HeapTuple tuple;
+
+ /*
+ * get information from the scan state
+ */
+ slot = node->ss.ss_ScanTupleSlot;
+ tsdesc = node->tsdesc;
+
+ tuple = tablesample_getnext(tsdesc);
+
+ if (tuple)
+ ExecStoreTuple(tuple, /* tuple to store */
+ slot, /* slot to store in */
+ tsdesc->heapScan->rs_cbuf, /* buffer associated with this tuple */
+ false); /* don't pfree this pointer */
+ else
+ ExecClearTuple(slot);
+
+ return slot;
+}
+
+/*
+ * SampleRecheck -- access method routine to recheck a tuple in EvalPlanQual
+ */
+static bool
+SampleRecheck(SampleScanState *node, TupleTableSlot *slot)
+{
+ /* No need to recheck for SampleScan */
+ return true;
+}
+
+/* ----------------------------------------------------------------
+ * ExecSampleScan(node)
+ *
+ * Scans the relation using the sampling method and returns
+ * the next qualifying tuple.
+ * We call the ExecScan() routine and pass it the appropriate
+ * access method functions.
+ * ----------------------------------------------------------------
+ */
+TupleTableSlot *
+ExecSampleScan(SampleScanState *node)
+{
+ return ExecScan((ScanState *) node,
+ (ExecScanAccessMtd) SampleNext,
+ (ExecScanRecheckMtd) SampleRecheck);
+}
+
+/* ----------------------------------------------------------------
+ * InitScanRelation
+ *
+ * Set up to access the scan relation.
+ * ----------------------------------------------------------------
+ */
+static void
+InitScanRelation(SampleScanState *node, EState *estate, int eflags,
+ TableSampleClause *tablesample)
+{
+ Relation currentRelation;
+
+ /*
+ * get the relation object id from the relid'th entry in the range table,
+ * open that relation and acquire appropriate lock on it.
+ */
+ currentRelation = ExecOpenScanRelation(estate,
+ ((SampleScan *) node->ss.ps.plan)->scanrelid,
+ eflags);
+
+ node->ss.ss_currentRelation = currentRelation;
+
+ /*
+ * Even though we aren't going to do a conventional seqscan, it is useful
+ * to create a HeapScanDesc --- many of the fields in it are usable.
+ */
+ node->ss.ss_currentScanDesc =
+ heap_beginscan_sampling(currentRelation, estate->es_snapshot, 0, NULL,
+ tablesample->tsmseqscan,
+ tablesample->tsmpagemode);
+
+ /* and report the scan tuple slot's rowtype */
+ ExecAssignScanType(&node->ss, RelationGetDescr(currentRelation));
+}
+
+
+/* ----------------------------------------------------------------
+ * ExecInitSampleScan
+ * ----------------------------------------------------------------
+ */
+SampleScanState *
+ExecInitSampleScan(SampleScan *node, EState *estate, int eflags)
+{
+ SampleScanState *scanstate;
+ RangeTblEntry *rte = rt_fetch(node->scanrelid,
+ estate->es_range_table);
+
+ Assert(outerPlan(node) == NULL);
+ Assert(innerPlan(node) == NULL);
+ Assert(rte->tablesample != NULL);
+
+ /*
+ * create state structure
+ */
+ scanstate = makeNode(SampleScanState);
+ scanstate->ss.ps.plan = (Plan *) node;
+ scanstate->ss.ps.state = estate;
+
+ /*
+ * Miscellaneous initialization
+ *
+ * create expression context for node
+ */
+ ExecAssignExprContext(estate, &scanstate->ss.ps);
+
+ /*
+ * initialize child expressions
+ */
+ scanstate->ss.ps.targetlist = (List *)
+ ExecInitExpr((Expr *) node->plan.targetlist,
+ (PlanState *) scanstate);
+ scanstate->ss.ps.qual = (List *)
+ ExecInitExpr((Expr *) node->plan.qual,
+ (PlanState *) scanstate);
+
+ /*
+ * tuple table initialization
+ */
+ ExecInitResultTupleSlot(estate, &scanstate->ss.ps);
+ ExecInitScanTupleSlot(estate, &scanstate->ss);
+
+ /*
+ * initialize scan relation
+ */
+ InitScanRelation(scanstate, estate, eflags, rte->tablesample);
+
+ scanstate->ss.ps.ps_TupFromTlist = false;
+
+ /*
+ * Initialize result tuple type and projection info.
+ */
+ ExecAssignResultTypeFromTL(&scanstate->ss.ps);
+ ExecAssignScanProjectionInfo(&scanstate->ss);
+
+ scanstate->tsdesc = tablesample_init(scanstate, rte->tablesample);
+
+ return scanstate;
+}
+
+/* ----------------------------------------------------------------
+ * ExecEndSampleScan
+ *
+ * frees any storage allocated through C routines.
+ * ----------------------------------------------------------------
+ */
+void
+ExecEndSampleScan(SampleScanState *node)
+{
+ /*
+ * Tell sampling function that we finished the scan.
+ */
+ tablesample_end(node->tsdesc);
+
+ /*
+ * Free the exprcontext
+ */
+ ExecFreeExprContext(&node->ss.ps);
+
+ /*
+ * clean out the tuple table
+ */
+ ExecClearTuple(node->ss.ps.ps_ResultTupleSlot);
+ ExecClearTuple(node->ss.ss_ScanTupleSlot);
+
+ /*
+ * close heap scan
+ */
+ heap_endscan(node->ss.ss_currentScanDesc);
+
+ /*
+ * close the heap relation.
+ */
+ ExecCloseScanRelation(node->ss.ss_currentRelation);
+}
+
+/* ----------------------------------------------------------------
+ * Join Support
+ * ----------------------------------------------------------------
+ */
+
+/* ----------------------------------------------------------------
+ * ExecReScanSampleScan
+ *
+ * Rescans the relation.
+ *
+ * ----------------------------------------------------------------
+ */
+void
+ExecReScanSampleScan(SampleScanState *node)
+{
+ heap_rescan(node->ss.ss_currentScanDesc, NULL);
+
+ /*
+ * Tell sampling function to reset its state for rescan.
+ */
+ tablesample_reset(node->tsdesc);
+
+ ExecScanReScan(&node->ss);
+}
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-22 08:52:50 +0000