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nodeSamplescan.h File Reference
#include "nodes/execnodes.h"
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Functions

SampleScanStateExecInitSampleScan (SampleScan *node, EState *estate, int eflags)
 
void ExecEndSampleScan (SampleScanState *node)
 
void ExecReScanSampleScan (SampleScanState *node)
 

Function Documentation

◆ ExecEndSampleScan()

void ExecEndSampleScan ( SampleScanState node)

Definition at line 179 of file nodeSamplescan.c.

180{
181 /*
182 * Tell sampling function that we finished the scan.
183 */
184 if (node->tsmroutine->EndSampleScan)
185 node->tsmroutine->EndSampleScan(node);
186
187 /*
188 * close heap scan
189 */
190 if (node->ss.ss_currentScanDesc)
192}
ScanState ss
Definition: execnodes.h:1594
struct TsmRoutine * tsmroutine
Definition: execnodes.h:1598
struct TableScanDescData * ss_currentScanDesc
Definition: execnodes.h:1574
EndSampleScan_function EndSampleScan
Definition: tsmapi.h:75
static void table_endscan(TableScanDesc scan)
Definition: tableam.h:1024

References TsmRoutine::EndSampleScan, SampleScanState::ss, ScanState::ss_currentScanDesc, table_endscan(), and SampleScanState::tsmroutine.

Referenced by ExecEndNode().

◆ ExecInitSampleScan()

SampleScanState * ExecInitSampleScan ( SampleScan node,
EState estate,
int  eflags 
)

Definition at line 93 of file nodeSamplescan.c.

94{
95 SampleScanState *scanstate;
96 TableSampleClause *tsc = node->tablesample;
97 TsmRoutine *tsm;
98
99 Assert(outerPlan(node) == NULL);
100 Assert(innerPlan(node) == NULL);
101
102 /*
103 * create state structure
104 */
105 scanstate = makeNode(SampleScanState);
106 scanstate->ss.ps.plan = (Plan *) node;
107 scanstate->ss.ps.state = estate;
108 scanstate->ss.ps.ExecProcNode = ExecSampleScan;
109
110 /*
111 * Miscellaneous initialization
112 *
113 * create expression context for node
114 */
115 ExecAssignExprContext(estate, &scanstate->ss.ps);
116
117 /*
118 * open the scan relation
119 */
120 scanstate->ss.ss_currentRelation =
122 node->scan.scanrelid,
123 eflags);
124
125 /* we won't set up the HeapScanDesc till later */
126 scanstate->ss.ss_currentScanDesc = NULL;
127
128 /* and create slot with appropriate rowtype */
129 ExecInitScanTupleSlot(estate, &scanstate->ss,
132
133 /*
134 * Initialize result type and projection.
135 */
136 ExecInitResultTypeTL(&scanstate->ss.ps);
137 ExecAssignScanProjectionInfo(&scanstate->ss);
138
139 /*
140 * initialize child expressions
141 */
142 scanstate->ss.ps.qual =
143 ExecInitQual(node->scan.plan.qual, (PlanState *) scanstate);
144
145 scanstate->args = ExecInitExprList(tsc->args, (PlanState *) scanstate);
146 scanstate->repeatable =
147 ExecInitExpr(tsc->repeatable, (PlanState *) scanstate);
148
149 /*
150 * If we don't have a REPEATABLE clause, select a random seed. We want to
151 * do this just once, since the seed shouldn't change over rescans.
152 */
153 if (tsc->repeatable == NULL)
155
156 /*
157 * Finally, initialize the TABLESAMPLE method handler.
158 */
159 tsm = GetTsmRoutine(tsc->tsmhandler);
160 scanstate->tsmroutine = tsm;
161 scanstate->tsm_state = NULL;
162
163 if (tsm->InitSampleScan)
164 tsm->InitSampleScan(scanstate, eflags);
165
166 /* We'll do BeginSampleScan later; we can't evaluate params yet */
167 scanstate->begun = false;
168
169 return scanstate;
170}
#define Assert(condition)
Definition: c.h:812
ExprState * ExecInitExpr(Expr *node, PlanState *parent)
Definition: execExpr.c:138
ExprState * ExecInitQual(List *qual, PlanState *parent)
Definition: execExpr.c:224
List * ExecInitExprList(List *nodes, PlanState *parent)
Definition: execExpr.c:330
void ExecAssignScanProjectionInfo(ScanState *node)
Definition: execScan.c:270
void ExecInitScanTupleSlot(EState *estate, ScanState *scanstate, TupleDesc tupledesc, const TupleTableSlotOps *tts_ops)
Definition: execTuples.c:1998
void ExecInitResultTypeTL(PlanState *planstate)
Definition: execTuples.c:1942
void ExecAssignExprContext(EState *estate, PlanState *planstate)
Definition: execUtils.c:485
Relation ExecOpenScanRelation(EState *estate, Index scanrelid, int eflags)
Definition: execUtils.c:742
static TupleTableSlot * ExecSampleScan(PlanState *pstate)
#define makeNode(_type_)
Definition: nodes.h:155
uint32 pg_prng_uint32(pg_prng_state *state)
Definition: pg_prng.c:227
pg_prng_state pg_global_prng_state
Definition: pg_prng.c:34
#define innerPlan(node)
Definition: plannodes.h:182
#define outerPlan(node)
Definition: plannodes.h:183
#define RelationGetDescr(relation)
Definition: rel.h:531
ExprState * qual
Definition: execnodes.h:1146
Plan * plan
Definition: execnodes.h:1125
EState * state
Definition: execnodes.h:1127
ExecProcNodeMtd ExecProcNode
Definition: execnodes.h:1131
ExprState * repeatable
Definition: execnodes.h:1596
void * tsm_state
Definition: execnodes.h:1599
struct TableSampleClause * tablesample
Definition: plannodes.h:410
Scan scan
Definition: plannodes.h:408
Relation ss_currentRelation
Definition: execnodes.h:1573
PlanState ps
Definition: execnodes.h:1572
Index scanrelid
Definition: plannodes.h:390
InitSampleScan_function InitSampleScan
Definition: tsmapi.h:71
const TupleTableSlotOps * table_slot_callbacks(Relation relation)
Definition: tableam.c:58
TsmRoutine * GetTsmRoutine(Oid tsmhandler)
Definition: tablesample.c:27

References SampleScanState::args, TableSampleClause::args, Assert, SampleScanState::begun, ExecAssignExprContext(), ExecAssignScanProjectionInfo(), ExecInitExpr(), ExecInitExprList(), ExecInitQual(), ExecInitResultTypeTL(), ExecInitScanTupleSlot(), ExecOpenScanRelation(), PlanState::ExecProcNode, ExecSampleScan(), GetTsmRoutine(), TsmRoutine::InitSampleScan, innerPlan, makeNode, outerPlan, pg_global_prng_state, pg_prng_uint32(), PlanState::plan, ScanState::ps, PlanState::qual, RelationGetDescr, SampleScanState::repeatable, TableSampleClause::repeatable, SampleScan::scan, Scan::scanrelid, SampleScanState::seed, SampleScanState::ss, ScanState::ss_currentRelation, ScanState::ss_currentScanDesc, PlanState::state, table_slot_callbacks(), SampleScan::tablesample, SampleScanState::tsm_state, TableSampleClause::tsmhandler, and SampleScanState::tsmroutine.

Referenced by ExecInitNode().

◆ ExecReScanSampleScan()

void ExecReScanSampleScan ( SampleScanState node)

Definition at line 202 of file nodeSamplescan.c.

203{
204 /* Remember we need to do BeginSampleScan again (if we did it at all) */
205 node->begun = false;
206 node->done = false;
207 node->haveblock = false;
208 node->donetuples = 0;
209
210 ExecScanReScan(&node->ss);
211}
void ExecScanReScan(ScanState *node)
Definition: execScan.c:297

References SampleScanState::begun, SampleScanState::done, SampleScanState::donetuples, ExecScanReScan(), SampleScanState::haveblock, and SampleScanState::ss.

Referenced by ExecReScan().