PostgreSQL Source Code  git master
nodeIndexonlyscan.c File Reference
#include "postgres.h"
#include "access/genam.h"
#include "access/relscan.h"
#include "access/tableam.h"
#include "access/tupdesc.h"
#include "access/visibilitymap.h"
#include "executor/execdebug.h"
#include "executor/nodeIndexonlyscan.h"
#include "executor/nodeIndexscan.h"
#include "miscadmin.h"
#include "storage/bufmgr.h"
#include "storage/predicate.h"
#include "utils/memutils.h"
#include "utils/rel.h"
Include dependency graph for nodeIndexonlyscan.c:

Go to the source code of this file.

Functions

static TupleTableSlotIndexOnlyNext (IndexOnlyScanState *node)
 
static void StoreIndexTuple (TupleTableSlot *slot, IndexTuple itup, TupleDesc itupdesc)
 
static bool IndexOnlyRecheck (IndexOnlyScanState *node, TupleTableSlot *slot)
 
static TupleTableSlotExecIndexOnlyScan (PlanState *pstate)
 
void ExecReScanIndexOnlyScan (IndexOnlyScanState *node)
 
void ExecEndIndexOnlyScan (IndexOnlyScanState *node)
 
void ExecIndexOnlyMarkPos (IndexOnlyScanState *node)
 
void ExecIndexOnlyRestrPos (IndexOnlyScanState *node)
 
IndexOnlyScanStateExecInitIndexOnlyScan (IndexOnlyScan *node, EState *estate, int eflags)
 
void ExecIndexOnlyScanEstimate (IndexOnlyScanState *node, ParallelContext *pcxt)
 
void ExecIndexOnlyScanInitializeDSM (IndexOnlyScanState *node, ParallelContext *pcxt)
 
void ExecIndexOnlyScanReInitializeDSM (IndexOnlyScanState *node, ParallelContext *pcxt)
 
void ExecIndexOnlyScanInitializeWorker (IndexOnlyScanState *node, ParallelWorkerContext *pwcxt)
 

Function Documentation

◆ ExecEndIndexOnlyScan()

void ExecEndIndexOnlyScan ( IndexOnlyScanState node)

Definition at line 365 of file nodeIndexonlyscan.c.

366 {
367  Relation indexRelationDesc;
368  IndexScanDesc indexScanDesc;
369 
370  /*
371  * extract information from the node
372  */
373  indexRelationDesc = node->ioss_RelationDesc;
374  indexScanDesc = node->ioss_ScanDesc;
375 
376  /* Release VM buffer pin, if any. */
377  if (node->ioss_VMBuffer != InvalidBuffer)
378  {
381  }
382 
383  /*
384  * Free the exprcontext(s) ... now dead code, see ExecFreeExprContext
385  */
386 #ifdef NOT_USED
387  ExecFreeExprContext(&node->ss.ps);
388  if (node->ioss_RuntimeContext)
390 #endif
391 
392  /*
393  * clear out tuple table slots
394  */
395  if (node->ss.ps.ps_ResultTupleSlot)
398 
399  /*
400  * close the index relation (no-op if we didn't open it)
401  */
402  if (indexScanDesc)
403  index_endscan(indexScanDesc);
404  if (indexRelationDesc)
405  index_close(indexRelationDesc, NoLock);
406 }
#define InvalidBuffer
Definition: buf.h:25
void ReleaseBuffer(Buffer buffer)
Definition: bufmgr.c:4480
void FreeExprContext(ExprContext *econtext, bool isCommit)
Definition: execUtils.c:419
void ExecFreeExprContext(PlanState *planstate)
Definition: execUtils.c:658
void index_close(Relation relation, LOCKMODE lockmode)
Definition: indexam.c:158
void index_endscan(IndexScanDesc scan)
Definition: indexam.c:327
#define NoLock
Definition: lockdefs.h:34
struct IndexScanDescData * ioss_ScanDesc
Definition: execnodes.h:1618
ExprContext * ioss_RuntimeContext
Definition: execnodes.h:1616
Relation ioss_RelationDesc
Definition: execnodes.h:1617
TupleTableSlot * ps_ResultTupleSlot
Definition: execnodes.h:1075
TupleTableSlot * ss_ScanTupleSlot
Definition: execnodes.h:1477
PlanState ps
Definition: execnodes.h:1474
static TupleTableSlot * ExecClearTuple(TupleTableSlot *slot)
Definition: tuptable.h:432

References ExecClearTuple(), ExecFreeExprContext(), FreeExprContext(), index_close(), index_endscan(), InvalidBuffer, IndexOnlyScanState::ioss_RelationDesc, IndexOnlyScanState::ioss_RuntimeContext, IndexOnlyScanState::ioss_ScanDesc, IndexOnlyScanState::ioss_VMBuffer, NoLock, ScanState::ps, PlanState::ps_ResultTupleSlot, ReleaseBuffer(), IndexOnlyScanState::ss, and ScanState::ss_ScanTupleSlot.

Referenced by ExecEndNode().

◆ ExecIndexOnlyMarkPos()

void ExecIndexOnlyMarkPos ( IndexOnlyScanState node)

Definition at line 416 of file nodeIndexonlyscan.c.

417 {
418  EState *estate = node->ss.ps.state;
419  EPQState *epqstate = estate->es_epq_active;
420 
421  if (epqstate != NULL)
422  {
423  /*
424  * We are inside an EvalPlanQual recheck. If a test tuple exists for
425  * this relation, then we shouldn't access the index at all. We would
426  * instead need to save, and later restore, the state of the
427  * relsubs_done flag, so that re-fetching the test tuple is possible.
428  * However, given the assumption that no caller sets a mark at the
429  * start of the scan, we can only get here with relsubs_done[i]
430  * already set, and so no state need be saved.
431  */
432  Index scanrelid = ((Scan *) node->ss.ps.plan)->scanrelid;
433 
434  Assert(scanrelid > 0);
435  if (epqstate->relsubs_slot[scanrelid - 1] != NULL ||
436  epqstate->relsubs_rowmark[scanrelid - 1] != NULL)
437  {
438  /* Verify the claim above */
439  if (!epqstate->relsubs_done[scanrelid - 1])
440  elog(ERROR, "unexpected ExecIndexOnlyMarkPos call in EPQ recheck");
441  return;
442  }
443  }
444 
446 }
unsigned int Index
Definition: c.h:603
#define ERROR
Definition: elog.h:39
void index_markpos(IndexScanDesc scan)
Definition: indexam.c:357
Assert(fmt[strlen(fmt) - 1] !='\n')
ExecAuxRowMark ** relsubs_rowmark
Definition: execnodes.h:1212
TupleTableSlot ** relsubs_slot
Definition: execnodes.h:1184
bool * relsubs_done
Definition: execnodes.h:1219
struct EPQState * es_epq_active
Definition: execnodes.h:691
Plan * plan
Definition: execnodes.h:1037
EState * state
Definition: execnodes.h:1039

References Assert(), elog(), ERROR, EState::es_epq_active, index_markpos(), IndexOnlyScanState::ioss_ScanDesc, PlanState::plan, ScanState::ps, EPQState::relsubs_done, EPQState::relsubs_rowmark, EPQState::relsubs_slot, IndexOnlyScanState::ss, and PlanState::state.

Referenced by ExecMarkPos().

◆ ExecIndexOnlyRestrPos()

void ExecIndexOnlyRestrPos ( IndexOnlyScanState node)

Definition at line 453 of file nodeIndexonlyscan.c.

454 {
455  EState *estate = node->ss.ps.state;
456  EPQState *epqstate = estate->es_epq_active;
457 
458  if (estate->es_epq_active != NULL)
459  {
460  /* See comments in ExecIndexMarkPos */
461  Index scanrelid = ((Scan *) node->ss.ps.plan)->scanrelid;
462 
463  Assert(scanrelid > 0);
464  if (epqstate->relsubs_slot[scanrelid - 1] != NULL ||
465  epqstate->relsubs_rowmark[scanrelid - 1] != NULL)
466  {
467  /* Verify the claim above */
468  if (!epqstate->relsubs_done[scanrelid - 1])
469  elog(ERROR, "unexpected ExecIndexOnlyRestrPos call in EPQ recheck");
470  return;
471  }
472  }
473 
475 }
void index_restrpos(IndexScanDesc scan)
Definition: indexam.c:381

References Assert(), elog(), ERROR, EState::es_epq_active, index_restrpos(), IndexOnlyScanState::ioss_ScanDesc, PlanState::plan, ScanState::ps, EPQState::relsubs_done, EPQState::relsubs_rowmark, EPQState::relsubs_slot, IndexOnlyScanState::ss, and PlanState::state.

Referenced by ExecRestrPos().

◆ ExecIndexOnlyScan()

static TupleTableSlot* ExecIndexOnlyScan ( PlanState pstate)
static

Definition at line 303 of file nodeIndexonlyscan.c.

304 {
306 
307  /*
308  * If we have runtime keys and they've not already been set up, do it now.
309  */
310  if (node->ioss_NumRuntimeKeys != 0 && !node->ioss_RuntimeKeysReady)
311  ExecReScan((PlanState *) node);
312 
313  return ExecScan(&node->ss,
316 }
void ExecReScan(PlanState *node)
Definition: execAmi.c:78
TupleTableSlot * ExecScan(ScanState *node, ExecScanAccessMtd accessMtd, ExecScanRecheckMtd recheckMtd)
Definition: execScan.c:157
TupleTableSlot *(* ExecScanAccessMtd)(ScanState *node)
Definition: executor.h:472
bool(* ExecScanRecheckMtd)(ScanState *node, TupleTableSlot *slot)
Definition: executor.h:473
static TupleTableSlot * IndexOnlyNext(IndexOnlyScanState *node)
static bool IndexOnlyRecheck(IndexOnlyScanState *node, TupleTableSlot *slot)
#define castNode(_type_, nodeptr)
Definition: nodes.h:197
bool ioss_RuntimeKeysReady
Definition: execnodes.h:1615

References castNode, ExecReScan(), ExecScan(), IndexOnlyNext(), IndexOnlyRecheck(), IndexOnlyScanState::ioss_NumRuntimeKeys, IndexOnlyScanState::ioss_RuntimeKeysReady, and IndexOnlyScanState::ss.

Referenced by ExecInitIndexOnlyScan().

◆ ExecIndexOnlyScanEstimate()

void ExecIndexOnlyScanEstimate ( IndexOnlyScanState node,
ParallelContext pcxt 
)

Definition at line 642 of file nodeIndexonlyscan.c.

644 {
645  EState *estate = node->ss.ps.state;
646 
648  estate->es_snapshot);
650  shm_toc_estimate_keys(&pcxt->estimator, 1);
651 }
Size index_parallelscan_estimate(Relation indexRelation, Snapshot snapshot)
Definition: indexam.c:406
#define shm_toc_estimate_chunk(e, sz)
Definition: shm_toc.h:51
#define shm_toc_estimate_keys(e, cnt)
Definition: shm_toc.h:53
Snapshot es_snapshot
Definition: execnodes.h:616
shm_toc_estimator estimator
Definition: parallel.h:42

References EState::es_snapshot, ParallelContext::estimator, index_parallelscan_estimate(), IndexOnlyScanState::ioss_PscanLen, IndexOnlyScanState::ioss_RelationDesc, ScanState::ps, shm_toc_estimate_chunk, shm_toc_estimate_keys, IndexOnlyScanState::ss, and PlanState::state.

Referenced by ExecParallelEstimate().

◆ ExecIndexOnlyScanInitializeDSM()

void ExecIndexOnlyScanInitializeDSM ( IndexOnlyScanState node,
ParallelContext pcxt 
)

Definition at line 660 of file nodeIndexonlyscan.c.

662 {
663  EState *estate = node->ss.ps.state;
664  ParallelIndexScanDesc piscan;
665 
666  piscan = shm_toc_allocate(pcxt->toc, node->ioss_PscanLen);
668  node->ioss_RelationDesc,
669  estate->es_snapshot,
670  piscan);
671  shm_toc_insert(pcxt->toc, node->ss.ps.plan->plan_node_id, piscan);
672  node->ioss_ScanDesc =
674  node->ioss_RelationDesc,
675  node->ioss_NumScanKeys,
676  node->ioss_NumOrderByKeys,
677  piscan);
678  node->ioss_ScanDesc->xs_want_itup = true;
680 
681  /*
682  * If no run-time keys to calculate or they are ready, go ahead and pass
683  * the scankeys to the index AM.
684  */
685  if (node->ioss_NumRuntimeKeys == 0 || node->ioss_RuntimeKeysReady)
687  node->ioss_ScanKeys, node->ioss_NumScanKeys,
689 }
IndexScanDesc index_beginscan_parallel(Relation heaprel, Relation indexrel, int nkeys, int norderbys, ParallelIndexScanDesc pscan)
Definition: indexam.c:492
void index_parallelscan_initialize(Relation heapRelation, Relation indexRelation, Snapshot snapshot, ParallelIndexScanDesc target)
Definition: indexam.c:441
void index_rescan(IndexScanDesc scan, ScanKey keys, int nkeys, ScanKey orderbys, int norderbys)
Definition: indexam.c:301
void shm_toc_insert(shm_toc *toc, uint64 key, void *address)
Definition: shm_toc.c:171
void * shm_toc_allocate(shm_toc *toc, Size nbytes)
Definition: shm_toc.c:88
struct ScanKeyData * ioss_ScanKeys
Definition: execnodes.h:1609
struct ScanKeyData * ioss_OrderByKeys
Definition: execnodes.h:1611
shm_toc * toc
Definition: parallel.h:45
int plan_node_id
Definition: plannodes.h:152
Relation ss_currentRelation
Definition: execnodes.h:1475

References EState::es_snapshot, index_beginscan_parallel(), index_parallelscan_initialize(), index_rescan(), InvalidBuffer, IndexOnlyScanState::ioss_NumOrderByKeys, IndexOnlyScanState::ioss_NumRuntimeKeys, IndexOnlyScanState::ioss_NumScanKeys, IndexOnlyScanState::ioss_OrderByKeys, IndexOnlyScanState::ioss_PscanLen, IndexOnlyScanState::ioss_RelationDesc, IndexOnlyScanState::ioss_RuntimeKeysReady, IndexOnlyScanState::ioss_ScanDesc, IndexOnlyScanState::ioss_ScanKeys, IndexOnlyScanState::ioss_VMBuffer, PlanState::plan, Plan::plan_node_id, ScanState::ps, shm_toc_allocate(), shm_toc_insert(), IndexOnlyScanState::ss, ScanState::ss_currentRelation, PlanState::state, ParallelContext::toc, and IndexScanDescData::xs_want_itup.

Referenced by ExecParallelInitializeDSM().

◆ ExecIndexOnlyScanInitializeWorker()

void ExecIndexOnlyScanInitializeWorker ( IndexOnlyScanState node,
ParallelWorkerContext pwcxt 
)

Definition at line 711 of file nodeIndexonlyscan.c.

713 {
714  ParallelIndexScanDesc piscan;
715 
716  piscan = shm_toc_lookup(pwcxt->toc, node->ss.ps.plan->plan_node_id, false);
717  node->ioss_ScanDesc =
719  node->ioss_RelationDesc,
720  node->ioss_NumScanKeys,
721  node->ioss_NumOrderByKeys,
722  piscan);
723  node->ioss_ScanDesc->xs_want_itup = true;
724 
725  /*
726  * If no run-time keys to calculate or they are ready, go ahead and pass
727  * the scankeys to the index AM.
728  */
729  if (node->ioss_NumRuntimeKeys == 0 || node->ioss_RuntimeKeysReady)
731  node->ioss_ScanKeys, node->ioss_NumScanKeys,
733 }
void * shm_toc_lookup(shm_toc *toc, uint64 key, bool noError)
Definition: shm_toc.c:232

References index_beginscan_parallel(), index_rescan(), IndexOnlyScanState::ioss_NumOrderByKeys, IndexOnlyScanState::ioss_NumRuntimeKeys, IndexOnlyScanState::ioss_NumScanKeys, IndexOnlyScanState::ioss_OrderByKeys, IndexOnlyScanState::ioss_RelationDesc, IndexOnlyScanState::ioss_RuntimeKeysReady, IndexOnlyScanState::ioss_ScanDesc, IndexOnlyScanState::ioss_ScanKeys, PlanState::plan, Plan::plan_node_id, ScanState::ps, shm_toc_lookup(), IndexOnlyScanState::ss, ScanState::ss_currentRelation, ParallelWorkerContext::toc, and IndexScanDescData::xs_want_itup.

Referenced by ExecParallelInitializeWorker().

◆ ExecIndexOnlyScanReInitializeDSM()

void ExecIndexOnlyScanReInitializeDSM ( IndexOnlyScanState node,
ParallelContext pcxt 
)

Definition at line 698 of file nodeIndexonlyscan.c.

700 {
702 }
void index_parallelrescan(IndexScanDesc scan)
Definition: indexam.c:474

References index_parallelrescan(), and IndexOnlyScanState::ioss_ScanDesc.

Referenced by ExecParallelReInitializeDSM().

◆ ExecInitIndexOnlyScan()

IndexOnlyScanState* ExecInitIndexOnlyScan ( IndexOnlyScan node,
EState estate,
int  eflags 
)

Definition at line 489 of file nodeIndexonlyscan.c.

490 {
491  IndexOnlyScanState *indexstate;
492  Relation currentRelation;
493  LOCKMODE lockmode;
494  TupleDesc tupDesc;
495 
496  /*
497  * create state structure
498  */
499  indexstate = makeNode(IndexOnlyScanState);
500  indexstate->ss.ps.plan = (Plan *) node;
501  indexstate->ss.ps.state = estate;
502  indexstate->ss.ps.ExecProcNode = ExecIndexOnlyScan;
503 
504  /*
505  * Miscellaneous initialization
506  *
507  * create expression context for node
508  */
509  ExecAssignExprContext(estate, &indexstate->ss.ps);
510 
511  /*
512  * open the scan relation
513  */
514  currentRelation = ExecOpenScanRelation(estate, node->scan.scanrelid, eflags);
515 
516  indexstate->ss.ss_currentRelation = currentRelation;
517  indexstate->ss.ss_currentScanDesc = NULL; /* no heap scan here */
518 
519  /*
520  * Build the scan tuple type using the indextlist generated by the
521  * planner. We use this, rather than the index's physical tuple
522  * descriptor, because the latter contains storage column types not the
523  * types of the original datums. (It's the AM's responsibility to return
524  * suitable data anyway.)
525  */
526  tupDesc = ExecTypeFromTL(node->indextlist);
527  ExecInitScanTupleSlot(estate, &indexstate->ss, tupDesc,
528  &TTSOpsVirtual);
529 
530  /*
531  * We need another slot, in a format that's suitable for the table AM, for
532  * when we need to fetch a tuple from the table for rechecking visibility.
533  */
534  indexstate->ioss_TableSlot =
536  RelationGetDescr(currentRelation),
537  table_slot_callbacks(currentRelation));
538 
539  /*
540  * Initialize result type and projection info. The node's targetlist will
541  * contain Vars with varno = INDEX_VAR, referencing the scan tuple.
542  */
543  ExecInitResultTypeTL(&indexstate->ss.ps);
545 
546  /*
547  * initialize child expressions
548  *
549  * Note: we don't initialize all of the indexorderby expression, only the
550  * sub-parts corresponding to runtime keys (see below).
551  */
552  indexstate->ss.ps.qual =
553  ExecInitQual(node->scan.plan.qual, (PlanState *) indexstate);
554  indexstate->recheckqual =
555  ExecInitQual(node->recheckqual, (PlanState *) indexstate);
556 
557  /*
558  * If we are just doing EXPLAIN (ie, aren't going to run the plan), stop
559  * here. This allows an index-advisor plugin to EXPLAIN a plan containing
560  * references to nonexistent indexes.
561  */
562  if (eflags & EXEC_FLAG_EXPLAIN_ONLY)
563  return indexstate;
564 
565  /* Open the index relation. */
566  lockmode = exec_rt_fetch(node->scan.scanrelid, estate)->rellockmode;
567  indexstate->ioss_RelationDesc = index_open(node->indexid, lockmode);
568 
569  /*
570  * Initialize index-specific scan state
571  */
572  indexstate->ioss_RuntimeKeysReady = false;
573  indexstate->ioss_RuntimeKeys = NULL;
574  indexstate->ioss_NumRuntimeKeys = 0;
575 
576  /*
577  * build the index scan keys from the index qualification
578  */
579  ExecIndexBuildScanKeys((PlanState *) indexstate,
580  indexstate->ioss_RelationDesc,
581  node->indexqual,
582  false,
583  &indexstate->ioss_ScanKeys,
584  &indexstate->ioss_NumScanKeys,
585  &indexstate->ioss_RuntimeKeys,
586  &indexstate->ioss_NumRuntimeKeys,
587  NULL, /* no ArrayKeys */
588  NULL);
589 
590  /*
591  * any ORDER BY exprs have to be turned into scankeys in the same way
592  */
593  ExecIndexBuildScanKeys((PlanState *) indexstate,
594  indexstate->ioss_RelationDesc,
595  node->indexorderby,
596  true,
597  &indexstate->ioss_OrderByKeys,
598  &indexstate->ioss_NumOrderByKeys,
599  &indexstate->ioss_RuntimeKeys,
600  &indexstate->ioss_NumRuntimeKeys,
601  NULL, /* no ArrayKeys */
602  NULL);
603 
604  /*
605  * If we have runtime keys, we need an ExprContext to evaluate them. The
606  * node's standard context won't do because we want to reset that context
607  * for every tuple. So, build another context just like the other one...
608  * -tgl 7/11/00
609  */
610  if (indexstate->ioss_NumRuntimeKeys != 0)
611  {
612  ExprContext *stdecontext = indexstate->ss.ps.ps_ExprContext;
613 
614  ExecAssignExprContext(estate, &indexstate->ss.ps);
615  indexstate->ioss_RuntimeContext = indexstate->ss.ps.ps_ExprContext;
616  indexstate->ss.ps.ps_ExprContext = stdecontext;
617  }
618  else
619  {
620  indexstate->ioss_RuntimeContext = NULL;
621  }
622 
623  /*
624  * all done.
625  */
626  return indexstate;
627 }
ExprState * ExecInitQual(List *qual, PlanState *parent)
Definition: execExpr.c:214
void ExecAssignScanProjectionInfoWithVarno(ScanState *node, int varno)
Definition: execScan.c:284
const TupleTableSlotOps TTSOpsVirtual
Definition: execTuples.c:83
void ExecInitScanTupleSlot(EState *estate, ScanState *scanstate, TupleDesc tupledesc, const TupleTableSlotOps *tts_ops)
Definition: execTuples.c:1812
void ExecInitResultTypeTL(PlanState *planstate)
Definition: execTuples.c:1756
TupleDesc ExecTypeFromTL(List *targetList)
Definition: execTuples.c:1939
TupleTableSlot * ExecAllocTableSlot(List **tupleTable, TupleDesc desc, const TupleTableSlotOps *tts_ops)
Definition: execTuples.c:1172
void ExecAssignExprContext(EState *estate, PlanState *planstate)
Definition: execUtils.c:488
Relation ExecOpenScanRelation(EState *estate, Index scanrelid, int eflags)
Definition: execUtils.c:728
static RangeTblEntry * exec_rt_fetch(Index rti, EState *estate)
Definition: executor.h:587
#define EXEC_FLAG_EXPLAIN_ONLY
Definition: executor.h:65
Relation index_open(Oid relationId, LOCKMODE lockmode)
Definition: indexam.c:132
int LOCKMODE
Definition: lockdefs.h:26
static TupleTableSlot * ExecIndexOnlyScan(PlanState *pstate)
void ExecIndexBuildScanKeys(PlanState *planstate, Relation index, List *quals, bool isorderby, ScanKey *scanKeys, int *numScanKeys, IndexRuntimeKeyInfo **runtimeKeys, int *numRuntimeKeys, IndexArrayKeyInfo **arrayKeys, int *numArrayKeys)
#define makeNode(_type_)
Definition: nodes.h:176
#define INDEX_VAR
Definition: primnodes.h:216
#define RelationGetDescr(relation)
Definition: rel.h:530
List * es_tupleTable
Definition: execnodes.h:661
TupleTableSlot * ioss_TableSlot
Definition: execnodes.h:1619
ExprState * recheckqual
Definition: execnodes.h:1608
IndexRuntimeKeyInfo * ioss_RuntimeKeys
Definition: execnodes.h:1613
List * indexqual
Definition: plannodes.h:494
List * recheckqual
Definition: plannodes.h:495
List * indextlist
Definition: plannodes.h:497
List * indexorderby
Definition: plannodes.h:496
ExprState * qual
Definition: execnodes.h:1058
ExprContext * ps_ExprContext
Definition: execnodes.h:1076
ExecProcNodeMtd ExecProcNode
Definition: execnodes.h:1043
struct TableScanDescData * ss_currentScanDesc
Definition: execnodes.h:1476
Index scanrelid
Definition: plannodes.h:387
const TupleTableSlotOps * table_slot_callbacks(Relation relation)
Definition: tableam.c:58

References EState::es_tupleTable, EXEC_FLAG_EXPLAIN_ONLY, exec_rt_fetch(), ExecAllocTableSlot(), ExecAssignExprContext(), ExecAssignScanProjectionInfoWithVarno(), ExecIndexBuildScanKeys(), ExecIndexOnlyScan(), ExecInitQual(), ExecInitResultTypeTL(), ExecInitScanTupleSlot(), ExecOpenScanRelation(), PlanState::ExecProcNode, ExecTypeFromTL(), index_open(), INDEX_VAR, IndexOnlyScan::indexid, IndexOnlyScan::indexorderby, IndexOnlyScan::indexqual, IndexOnlyScan::indextlist, IndexOnlyScanState::ioss_NumOrderByKeys, IndexOnlyScanState::ioss_NumRuntimeKeys, IndexOnlyScanState::ioss_NumScanKeys, IndexOnlyScanState::ioss_OrderByKeys, IndexOnlyScanState::ioss_RelationDesc, IndexOnlyScanState::ioss_RuntimeContext, IndexOnlyScanState::ioss_RuntimeKeys, IndexOnlyScanState::ioss_RuntimeKeysReady, IndexOnlyScanState::ioss_ScanKeys, IndexOnlyScanState::ioss_TableSlot, makeNode, PlanState::plan, ScanState::ps, PlanState::ps_ExprContext, PlanState::qual, IndexOnlyScanState::recheckqual, IndexOnlyScan::recheckqual, RelationGetDescr, RangeTblEntry::rellockmode, IndexOnlyScan::scan, Scan::scanrelid, IndexOnlyScanState::ss, ScanState::ss_currentRelation, ScanState::ss_currentScanDesc, PlanState::state, table_slot_callbacks(), and TTSOpsVirtual.

Referenced by ExecInitNode().

◆ ExecReScanIndexOnlyScan()

void ExecReScanIndexOnlyScan ( IndexOnlyScanState node)

Definition at line 330 of file nodeIndexonlyscan.c.

331 {
332  /*
333  * If we are doing runtime key calculations (ie, any of the index key
334  * values weren't simple Consts), compute the new key values. But first,
335  * reset the context so we don't leak memory as each outer tuple is
336  * scanned. Note this assumes that we will recalculate *all* runtime keys
337  * on each call.
338  */
339  if (node->ioss_NumRuntimeKeys != 0)
340  {
341  ExprContext *econtext = node->ioss_RuntimeContext;
342 
343  ResetExprContext(econtext);
344  ExecIndexEvalRuntimeKeys(econtext,
345  node->ioss_RuntimeKeys,
346  node->ioss_NumRuntimeKeys);
347  }
348  node->ioss_RuntimeKeysReady = true;
349 
350  /* reset index scan */
351  if (node->ioss_ScanDesc)
353  node->ioss_ScanKeys, node->ioss_NumScanKeys,
355 
356  ExecScanReScan(&node->ss);
357 }
void ExecScanReScan(ScanState *node)
Definition: execScan.c:298
#define ResetExprContext(econtext)
Definition: executor.h:543
void ExecIndexEvalRuntimeKeys(ExprContext *econtext, IndexRuntimeKeyInfo *runtimeKeys, int numRuntimeKeys)

References ExecIndexEvalRuntimeKeys(), ExecScanReScan(), index_rescan(), IndexOnlyScanState::ioss_NumOrderByKeys, IndexOnlyScanState::ioss_NumRuntimeKeys, IndexOnlyScanState::ioss_NumScanKeys, IndexOnlyScanState::ioss_OrderByKeys, IndexOnlyScanState::ioss_RuntimeContext, IndexOnlyScanState::ioss_RuntimeKeys, IndexOnlyScanState::ioss_RuntimeKeysReady, IndexOnlyScanState::ioss_ScanDesc, IndexOnlyScanState::ioss_ScanKeys, ResetExprContext, and IndexOnlyScanState::ss.

Referenced by ExecReScan().

◆ IndexOnlyNext()

static TupleTableSlot * IndexOnlyNext ( IndexOnlyScanState node)
static

Definition at line 60 of file nodeIndexonlyscan.c.

61 {
62  EState *estate;
63  ExprContext *econtext;
64  ScanDirection direction;
65  IndexScanDesc scandesc;
66  TupleTableSlot *slot;
67  ItemPointer tid;
68 
69  /*
70  * extract necessary information from index scan node
71  */
72  estate = node->ss.ps.state;
73 
74  /*
75  * Determine which direction to scan the index in based on the plan's scan
76  * direction and the current direction of execution.
77  */
78  direction = ScanDirectionCombine(estate->es_direction,
79  ((IndexOnlyScan *) node->ss.ps.plan)->indexorderdir);
80  scandesc = node->ioss_ScanDesc;
81  econtext = node->ss.ps.ps_ExprContext;
82  slot = node->ss.ss_ScanTupleSlot;
83 
84  if (scandesc == NULL)
85  {
86  /*
87  * We reach here if the index only scan is not parallel, or if we're
88  * serially executing an index only scan that was planned to be
89  * parallel.
90  */
91  scandesc = index_beginscan(node->ss.ss_currentRelation,
92  node->ioss_RelationDesc,
93  estate->es_snapshot,
94  node->ioss_NumScanKeys,
95  node->ioss_NumOrderByKeys);
96 
97  node->ioss_ScanDesc = scandesc;
98 
99 
100  /* Set it up for index-only scan */
101  node->ioss_ScanDesc->xs_want_itup = true;
103 
104  /*
105  * If no run-time keys to calculate or they are ready, go ahead and
106  * pass the scankeys to the index AM.
107  */
108  if (node->ioss_NumRuntimeKeys == 0 || node->ioss_RuntimeKeysReady)
109  index_rescan(scandesc,
110  node->ioss_ScanKeys,
111  node->ioss_NumScanKeys,
112  node->ioss_OrderByKeys,
113  node->ioss_NumOrderByKeys);
114  }
115 
116  /*
117  * OK, now that we have what we need, fetch the next tuple.
118  */
119  while ((tid = index_getnext_tid(scandesc, direction)) != NULL)
120  {
121  bool tuple_from_heap = false;
122 
124 
125  /*
126  * We can skip the heap fetch if the TID references a heap page on
127  * which all tuples are known visible to everybody. In any case,
128  * we'll use the index tuple not the heap tuple as the data source.
129  *
130  * Note on Memory Ordering Effects: visibilitymap_get_status does not
131  * lock the visibility map buffer, and therefore the result we read
132  * here could be slightly stale. However, it can't be stale enough to
133  * matter.
134  *
135  * We need to detect clearing a VM bit due to an insert right away,
136  * because the tuple is present in the index page but not visible. The
137  * reading of the TID by this scan (using a shared lock on the index
138  * buffer) is serialized with the insert of the TID into the index
139  * (using an exclusive lock on the index buffer). Because the VM bit
140  * is cleared before updating the index, and locking/unlocking of the
141  * index page acts as a full memory barrier, we are sure to see the
142  * cleared bit if we see a recently-inserted TID.
143  *
144  * Deletes do not update the index page (only VACUUM will clear out
145  * the TID), so the clearing of the VM bit by a delete is not
146  * serialized with this test below, and we may see a value that is
147  * significantly stale. However, we don't care about the delete right
148  * away, because the tuple is still visible until the deleting
149  * transaction commits or the statement ends (if it's our
150  * transaction). In either case, the lock on the VM buffer will have
151  * been released (acting as a write barrier) after clearing the bit.
152  * And for us to have a snapshot that includes the deleting
153  * transaction (making the tuple invisible), we must have acquired
154  * ProcArrayLock after that time, acting as a read barrier.
155  *
156  * It's worth going through this complexity to avoid needing to lock
157  * the VM buffer, which could cause significant contention.
158  */
159  if (!VM_ALL_VISIBLE(scandesc->heapRelation,
161  &node->ioss_VMBuffer))
162  {
163  /*
164  * Rats, we have to visit the heap to check visibility.
165  */
166  InstrCountTuples2(node, 1);
167  if (!index_fetch_heap(scandesc, node->ioss_TableSlot))
168  continue; /* no visible tuple, try next index entry */
169 
171 
172  /*
173  * Only MVCC snapshots are supported here, so there should be no
174  * need to keep following the HOT chain once a visible entry has
175  * been found. If we did want to allow that, we'd need to keep
176  * more state to remember not to call index_getnext_tid next time.
177  */
178  if (scandesc->xs_heap_continue)
179  elog(ERROR, "non-MVCC snapshots are not supported in index-only scans");
180 
181  /*
182  * Note: at this point we are holding a pin on the heap page, as
183  * recorded in scandesc->xs_cbuf. We could release that pin now,
184  * but it's not clear whether it's a win to do so. The next index
185  * entry might require a visit to the same heap page.
186  */
187 
188  tuple_from_heap = true;
189  }
190 
191  /*
192  * Fill the scan tuple slot with data from the index. This might be
193  * provided in either HeapTuple or IndexTuple format. Conceivably an
194  * index AM might fill both fields, in which case we prefer the heap
195  * format, since it's probably a bit cheaper to fill a slot from.
196  */
197  if (scandesc->xs_hitup)
198  {
199  /*
200  * We don't take the trouble to verify that the provided tuple has
201  * exactly the slot's format, but it seems worth doing a quick
202  * check on the number of fields.
203  */
205  scandesc->xs_hitupdesc->natts);
206  ExecForceStoreHeapTuple(scandesc->xs_hitup, slot, false);
207  }
208  else if (scandesc->xs_itup)
209  StoreIndexTuple(slot, scandesc->xs_itup, scandesc->xs_itupdesc);
210  else
211  elog(ERROR, "no data returned for index-only scan");
212 
213  /*
214  * If the index was lossy, we have to recheck the index quals.
215  */
216  if (scandesc->xs_recheck)
217  {
218  econtext->ecxt_scantuple = slot;
219  if (!ExecQualAndReset(node->recheckqual, econtext))
220  {
221  /* Fails recheck, so drop it and loop back for another */
222  InstrCountFiltered2(node, 1);
223  continue;
224  }
225  }
226 
227  /*
228  * We don't currently support rechecking ORDER BY distances. (In
229  * principle, if the index can support retrieval of the originally
230  * indexed value, it should be able to produce an exact distance
231  * calculation too. So it's not clear that adding code here for
232  * recheck/re-sort would be worth the trouble. But we should at least
233  * throw an error if someone tries it.)
234  */
235  if (scandesc->numberOfOrderBys > 0 && scandesc->xs_recheckorderby)
236  ereport(ERROR,
237  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
238  errmsg("lossy distance functions are not supported in index-only scans")));
239 
240  /*
241  * If we didn't access the heap, then we'll need to take a predicate
242  * lock explicitly, as if we had. For now we do that at page level.
243  */
244  if (!tuple_from_heap)
247  estate->es_snapshot);
248 
249  return slot;
250  }
251 
252  /*
253  * if we get here it means the index scan failed so we are at the end of
254  * the scan..
255  */
256  return ExecClearTuple(slot);
257 }
int errcode(int sqlerrcode)
Definition: elog.c:858
int errmsg(const char *fmt,...)
Definition: elog.c:1069
#define ereport(elevel,...)
Definition: elog.h:149
void ExecForceStoreHeapTuple(HeapTuple tuple, TupleTableSlot *slot, bool shouldFree)
Definition: execTuples.c:1470
#define InstrCountTuples2(node, delta)
Definition: execnodes.h:1136
#define InstrCountFiltered2(node, delta)
Definition: execnodes.h:1146
static bool ExecQualAndReset(ExprState *state, ExprContext *econtext)
Definition: executor.h:439
ItemPointer index_getnext_tid(IndexScanDesc scan, ScanDirection direction)
Definition: indexam.c:525
IndexScanDesc index_beginscan(Relation heapRelation, Relation indexRelation, Snapshot snapshot, int nkeys, int norderbys)
Definition: indexam.c:205
bool index_fetch_heap(IndexScanDesc scan, TupleTableSlot *slot)
Definition: indexam.c:583
static BlockNumber ItemPointerGetBlockNumber(const ItemPointerData *pointer)
Definition: itemptr.h:103
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:121
static void StoreIndexTuple(TupleTableSlot *slot, IndexTuple itup, TupleDesc itupdesc)
void PredicateLockPage(Relation relation, BlockNumber blkno, Snapshot snapshot)
Definition: predicate.c:2533
#define ScanDirectionCombine(a, b)
Definition: sdir.h:36
ScanDirection
Definition: sdir.h:25
ScanDirection es_direction
Definition: execnodes.h:615
TupleTableSlot * ecxt_scantuple
Definition: execnodes.h:249
bool xs_heap_continue
Definition: relscan.h:148
HeapTuple xs_hitup
Definition: relscan.h:144
int numberOfOrderBys
Definition: relscan.h:121
bool xs_recheckorderby
Definition: relscan.h:163
IndexTuple xs_itup
Definition: relscan.h:142
struct TupleDescData * xs_hitupdesc
Definition: relscan.h:145
struct TupleDescData * xs_itupdesc
Definition: relscan.h:143
Relation heapRelation
Definition: relscan.h:117
TupleDesc tts_tupleDescriptor
Definition: tuptable.h:123
#define VM_ALL_VISIBLE(r, b, v)
Definition: visibilitymap.h:24

References Assert(), CHECK_FOR_INTERRUPTS, ExprContext::ecxt_scantuple, elog(), ereport, errcode(), errmsg(), ERROR, EState::es_direction, EState::es_snapshot, ExecClearTuple(), ExecForceStoreHeapTuple(), ExecQualAndReset(), IndexScanDescData::heapRelation, index_beginscan(), index_fetch_heap(), index_getnext_tid(), index_rescan(), InstrCountFiltered2, InstrCountTuples2, InvalidBuffer, IndexOnlyScanState::ioss_NumOrderByKeys, IndexOnlyScanState::ioss_NumRuntimeKeys, IndexOnlyScanState::ioss_NumScanKeys, IndexOnlyScanState::ioss_OrderByKeys, IndexOnlyScanState::ioss_RelationDesc, IndexOnlyScanState::ioss_RuntimeKeysReady, IndexOnlyScanState::ioss_ScanDesc, IndexOnlyScanState::ioss_ScanKeys, IndexOnlyScanState::ioss_TableSlot, IndexOnlyScanState::ioss_VMBuffer, ItemPointerGetBlockNumber(), TupleDescData::natts, IndexScanDescData::numberOfOrderBys, PlanState::plan, PredicateLockPage(), ScanState::ps, PlanState::ps_ExprContext, IndexOnlyScanState::recheckqual, ScanDirectionCombine, IndexOnlyScanState::ss, ScanState::ss_currentRelation, ScanState::ss_ScanTupleSlot, PlanState::state, StoreIndexTuple(), TupleTableSlot::tts_tupleDescriptor, VM_ALL_VISIBLE, IndexScanDescData::xs_heap_continue, IndexScanDescData::xs_hitup, IndexScanDescData::xs_hitupdesc, IndexScanDescData::xs_itup, IndexScanDescData::xs_itupdesc, IndexScanDescData::xs_recheck, IndexScanDescData::xs_recheckorderby, and IndexScanDescData::xs_want_itup.

Referenced by ExecIndexOnlyScan().

◆ IndexOnlyRecheck()

static bool IndexOnlyRecheck ( IndexOnlyScanState node,
TupleTableSlot slot 
)
static

Definition at line 292 of file nodeIndexonlyscan.c.

293 {
294  elog(ERROR, "EvalPlanQual recheck is not supported in index-only scans");
295  return false; /* keep compiler quiet */
296 }

References elog(), and ERROR.

Referenced by ExecIndexOnlyScan().

◆ StoreIndexTuple()

static void StoreIndexTuple ( TupleTableSlot slot,
IndexTuple  itup,
TupleDesc  itupdesc 
)
static

Definition at line 267 of file nodeIndexonlyscan.c.

268 {
269  /*
270  * Note: we must use the tupdesc supplied by the AM in index_deform_tuple,
271  * not the slot's tupdesc, in case the latter has different datatypes
272  * (this happens for btree name_ops in particular). They'd better have
273  * the same number of columns though, as well as being datatype-compatible
274  * which is something we can't so easily check.
275  */
276  Assert(slot->tts_tupleDescriptor->natts == itupdesc->natts);
277 
278  ExecClearTuple(slot);
279  index_deform_tuple(itup, itupdesc, slot->tts_values, slot->tts_isnull);
280  ExecStoreVirtualTuple(slot);
281 }
TupleTableSlot * ExecStoreVirtualTuple(TupleTableSlot *slot)
Definition: execTuples.c:1553
void index_deform_tuple(IndexTuple tup, TupleDesc tupleDescriptor, Datum *values, bool *isnull)
Definition: indextuple.c:456
bool * tts_isnull
Definition: tuptable.h:127
Datum * tts_values
Definition: tuptable.h:125

References Assert(), ExecClearTuple(), ExecStoreVirtualTuple(), index_deform_tuple(), TupleDescData::natts, TupleTableSlot::tts_isnull, TupleTableSlot::tts_tupleDescriptor, and TupleTableSlot::tts_values.

Referenced by IndexOnlyNext().