PostgreSQL Source Code  git master
execScan.c File Reference
#include "postgres.h"
#include "executor/executor.h"
#include "miscadmin.h"
#include "utils/memutils.h"
Include dependency graph for execScan.c:

Go to the source code of this file.

Functions

static TupleTableSlotExecScanFetch (ScanState *node, ExecScanAccessMtd accessMtd, ExecScanRecheckMtd recheckMtd)
 
TupleTableSlotExecScan (ScanState *node, ExecScanAccessMtd accessMtd, ExecScanRecheckMtd recheckMtd)
 
void ExecAssignScanProjectionInfo (ScanState *node)
 
void ExecAssignScanProjectionInfoWithVarno (ScanState *node, Index varno)
 
void ExecScanReScan (ScanState *node)
 

Function Documentation

◆ ExecAssignScanProjectionInfo()

void ExecAssignScanProjectionInfo ( ScanState node)

◆ ExecAssignScanProjectionInfoWithVarno()

void ExecAssignScanProjectionInfoWithVarno ( ScanState node,
Index  varno 
)

Definition at line 248 of file execScan.c.

References ExecConditionalAssignProjectionInfo(), ScanState::ps, ScanState::ss_ScanTupleSlot, and TupleTableSlot::tts_tupleDescriptor.

Referenced by ExecInitCustomScan(), ExecInitForeignScan(), and ExecInitIndexOnlyScan().

249 {
251 
252  ExecConditionalAssignProjectionInfo(&node->ps, tupdesc, varno);
253 }
TupleTableSlot * ss_ScanTupleSlot
Definition: execnodes.h:1116
void ExecConditionalAssignProjectionInfo(PlanState *planstate, TupleDesc inputDesc, Index varno)
Definition: execUtils.c:515
PlanState ps
Definition: execnodes.h:1113
TupleDesc tts_tupleDescriptor
Definition: tuptable.h:121

◆ ExecScan()

TupleTableSlot* ExecScan ( ScanState node,
ExecScanAccessMtd  accessMtd,
ExecScanRecheckMtd  recheckMtd 
)

Definition at line 121 of file execScan.c.

References ExprContext::ecxt_scantuple, ExecClearTuple(), ExecProject(), ExecQual(), ExecScanFetch(), InstrCountFiltered1, ProjectionInfo::pi_state, ScanState::ps, PlanState::ps_ExprContext, PlanState::ps_ProjInfo, PlanState::qual, ResetExprContext, ExprState::resultslot, and TupIsNull.

Referenced by ExecBitmapHeapScan(), ExecCteScan(), ExecForeignScan(), ExecFunctionScan(), ExecIndexOnlyScan(), ExecIndexScan(), ExecNamedTuplestoreScan(), ExecSampleScan(), ExecSeqScan(), ExecSubqueryScan(), ExecTableFuncScan(), ExecTidScan(), ExecValuesScan(), and ExecWorkTableScan().

124 {
125  ExprContext *econtext;
126  ExprState *qual;
127  ProjectionInfo *projInfo;
128 
129  /*
130  * Fetch data from node
131  */
132  qual = node->ps.qual;
133  projInfo = node->ps.ps_ProjInfo;
134  econtext = node->ps.ps_ExprContext;
135 
136  /* interrupt checks are in ExecScanFetch */
137 
138  /*
139  * If we have neither a qual to check nor a projection to do, just skip
140  * all the overhead and return the raw scan tuple.
141  */
142  if (!qual && !projInfo)
143  {
144  ResetExprContext(econtext);
145  return ExecScanFetch(node, accessMtd, recheckMtd);
146  }
147 
148  /*
149  * Reset per-tuple memory context to free any expression evaluation
150  * storage allocated in the previous tuple cycle.
151  */
152  ResetExprContext(econtext);
153 
154  /*
155  * get a tuple from the access method. Loop until we obtain a tuple that
156  * passes the qualification.
157  */
158  for (;;)
159  {
160  TupleTableSlot *slot;
161 
162  slot = ExecScanFetch(node, accessMtd, recheckMtd);
163 
164  /*
165  * if the slot returned by the accessMtd contains NULL, then it means
166  * there is nothing more to scan so we just return an empty slot,
167  * being careful to use the projection result slot so it has correct
168  * tupleDesc.
169  */
170  if (TupIsNull(slot))
171  {
172  if (projInfo)
173  return ExecClearTuple(projInfo->pi_state.resultslot);
174  else
175  return slot;
176  }
177 
178  /*
179  * place the current tuple into the expr context
180  */
181  econtext->ecxt_scantuple = slot;
182 
183  /*
184  * check that the current tuple satisfies the qual-clause
185  *
186  * check for non-null qual here to avoid a function call to ExecQual()
187  * when the qual is null ... saves only a few cycles, but they add up
188  * ...
189  */
190  if (qual == NULL || ExecQual(qual, econtext))
191  {
192  /*
193  * Found a satisfactory scan tuple.
194  */
195  if (projInfo)
196  {
197  /*
198  * Form a projection tuple, store it in the result tuple slot
199  * and return it.
200  */
201  return ExecProject(projInfo);
202  }
203  else
204  {
205  /*
206  * Here, we aren't projecting, so just return scan tuple.
207  */
208  return slot;
209  }
210  }
211  else
212  InstrCountFiltered1(node, 1);
213 
214  /*
215  * Tuple fails qual, so free per-tuple memory and try again.
216  */
217  ResetExprContext(econtext);
218  }
219 }
ProjectionInfo * ps_ProjInfo
Definition: execnodes.h:885
static TupleTableSlot * ExecScanFetch(ScanState *node, ExecScanAccessMtd accessMtd, ExecScanRecheckMtd recheckMtd)
Definition: execScan.c:35
ExprContext * ps_ExprContext
Definition: execnodes.h:884
TupleTableSlot * ExecClearTuple(TupleTableSlot *slot)
Definition: execTuples.c:439
TupleTableSlot * resultslot
Definition: execnodes.h:70
static bool ExecQual(ExprState *state, ExprContext *econtext)
Definition: executor.h:356
PlanState ps
Definition: execnodes.h:1113
#define TupIsNull(slot)
Definition: tuptable.h:138
#define InstrCountFiltered1(node, delta)
Definition: execnodes.h:899
TupleTableSlot * ecxt_scantuple
Definition: execnodes.h:198
ExprState * qual
Definition: execnodes.h:868
ExprState pi_state
Definition: execnodes.h:297
static TupleTableSlot * ExecProject(ProjectionInfo *projInfo)
Definition: executor.h:319
#define ResetExprContext(econtext)
Definition: executor.h:461

◆ ExecScanFetch()

static TupleTableSlot* ExecScanFetch ( ScanState node,
ExecScanAccessMtd  accessMtd,
ExecScanRecheckMtd  recheckMtd 
)
inlinestatic

Definition at line 35 of file execScan.c.

References CHECK_FOR_INTERRUPTS, EState::es_epqScanDone, EState::es_epqTuple, EState::es_epqTupleSet, ExecClearTuple(), ExecStoreTuple(), InvalidBuffer, PlanState::plan, ScanState::ps, ScanState::ss_ScanTupleSlot, and PlanState::state.

Referenced by ExecScan().

38 {
39  EState *estate = node->ps.state;
40 
42 
43  if (estate->es_epqTuple != NULL)
44  {
45  /*
46  * We are inside an EvalPlanQual recheck. Return the test tuple if
47  * one is available, after rechecking any access-method-specific
48  * conditions.
49  */
50  Index scanrelid = ((Scan *) node->ps.plan)->scanrelid;
51 
52  if (scanrelid == 0)
53  {
54  TupleTableSlot *slot = node->ss_ScanTupleSlot;
55 
56  /*
57  * This is a ForeignScan or CustomScan which has pushed down a
58  * join to the remote side. The recheck method is responsible not
59  * only for rechecking the scan/join quals but also for storing
60  * the correct tuple in the slot.
61  */
62  if (!(*recheckMtd) (node, slot))
63  ExecClearTuple(slot); /* would not be returned by scan */
64  return slot;
65  }
66  else if (estate->es_epqTupleSet[scanrelid - 1])
67  {
68  TupleTableSlot *slot = node->ss_ScanTupleSlot;
69 
70  /* Return empty slot if we already returned a tuple */
71  if (estate->es_epqScanDone[scanrelid - 1])
72  return ExecClearTuple(slot);
73  /* Else mark to remember that we shouldn't return more */
74  estate->es_epqScanDone[scanrelid - 1] = true;
75 
76  /* Return empty slot if we haven't got a test tuple */
77  if (estate->es_epqTuple[scanrelid - 1] == NULL)
78  return ExecClearTuple(slot);
79 
80  /* Store test tuple in the plan node's scan slot */
81  ExecStoreTuple(estate->es_epqTuple[scanrelid - 1],
82  slot, InvalidBuffer, false);
83 
84  /* Check if it meets the access-method conditions */
85  if (!(*recheckMtd) (node, slot))
86  ExecClearTuple(slot); /* would not be returned by scan */
87 
88  return slot;
89  }
90  }
91 
92  /*
93  * Run the node-type-specific access method function to get the next tuple
94  */
95  return (*accessMtd) (node);
96 }
TupleTableSlot * ExecStoreTuple(HeapTuple tuple, TupleTableSlot *slot, Buffer buffer, bool shouldFree)
Definition: execTuples.c:320
HeapTuple * es_epqTuple
Definition: execnodes.h:507
TupleTableSlot * ExecClearTuple(TupleTableSlot *slot)
Definition: execTuples.c:439
#define InvalidBuffer
Definition: buf.h:25
TupleTableSlot * ss_ScanTupleSlot
Definition: execnodes.h:1116
EState * state
Definition: execnodes.h:852
PlanState ps
Definition: execnodes.h:1113
unsigned int Index
Definition: c.h:413
Plan * plan
Definition: execnodes.h:850
bool * es_epqTupleSet
Definition: execnodes.h:508
bool * es_epqScanDone
Definition: execnodes.h:509
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:98

◆ ExecScanReScan()

void ExecScanReScan ( ScanState node)

Definition at line 262 of file execScan.c.

References Assert, bms_next_member(), elog, ERROR, EState::es_epqScanDone, IsA, nodeTag, PlanState::plan, ScanState::ps, and PlanState::state.

Referenced by ExecReScanBitmapHeapScan(), ExecReScanCteScan(), ExecReScanForeignScan(), ExecReScanFunctionScan(), ExecReScanIndexOnlyScan(), ExecReScanIndexScan(), ExecReScanNamedTuplestoreScan(), ExecReScanSampleScan(), ExecReScanSeqScan(), ExecReScanSubqueryScan(), ExecReScanTableFuncScan(), ExecReScanTidScan(), ExecReScanValuesScan(), and ExecReScanWorkTableScan().

263 {
264  EState *estate = node->ps.state;
265 
266  /* Rescan EvalPlanQual tuple if we're inside an EvalPlanQual recheck */
267  if (estate->es_epqScanDone != NULL)
268  {
269  Index scanrelid = ((Scan *) node->ps.plan)->scanrelid;
270 
271  if (scanrelid > 0)
272  estate->es_epqScanDone[scanrelid - 1] = false;
273  else
274  {
275  Bitmapset *relids;
276  int rtindex = -1;
277 
278  /*
279  * If an FDW or custom scan provider has replaced the join with a
280  * scan, there are multiple RTIs; reset the epqScanDone flag for
281  * all of them.
282  */
283  if (IsA(node->ps.plan, ForeignScan))
284  relids = ((ForeignScan *) node->ps.plan)->fs_relids;
285  else if (IsA(node->ps.plan, CustomScan))
286  relids = ((CustomScan *) node->ps.plan)->custom_relids;
287  else
288  elog(ERROR, "unexpected scan node: %d",
289  (int) nodeTag(node->ps.plan));
290 
291  while ((rtindex = bms_next_member(relids, rtindex)) >= 0)
292  {
293  Assert(rtindex > 0);
294  estate->es_epqScanDone[rtindex - 1] = false;
295  }
296  }
297  }
298 }
#define IsA(nodeptr, _type_)
Definition: nodes.h:563
int bms_next_member(const Bitmapset *a, int prevbit)
Definition: bitmapset.c:1009
EState * state
Definition: execnodes.h:852
PlanState ps
Definition: execnodes.h:1113
#define ERROR
Definition: elog.h:43
unsigned int Index
Definition: c.h:413
Plan * plan
Definition: execnodes.h:850
#define Assert(condition)
Definition: c.h:670
#define nodeTag(nodeptr)
Definition: nodes.h:517
bool * es_epqScanDone
Definition: execnodes.h:509
#define elog
Definition: elog.h:219