PostgreSQL Source Code  git master
nodeGatherMerge.c File Reference
#include "postgres.h"
#include "access/relscan.h"
#include "access/xact.h"
#include "executor/execdebug.h"
#include "executor/execParallel.h"
#include "executor/nodeGatherMerge.h"
#include "executor/nodeSubplan.h"
#include "executor/tqueue.h"
#include "lib/binaryheap.h"
#include "miscadmin.h"
#include "optimizer/optimizer.h"
#include "utils/memutils.h"
#include "utils/rel.h"
Include dependency graph for nodeGatherMerge.c:

Go to the source code of this file.

Data Structures

struct  GMReaderTupleBuffer
 

Macros

#define MAX_TUPLE_STORE   10
 

Typedefs

typedef struct GMReaderTupleBuffer GMReaderTupleBuffer
 
typedef int32 SlotNumber
 

Functions

static TupleTableSlotExecGatherMerge (PlanState *pstate)
 
static int32 heap_compare_slots (Datum a, Datum b, void *arg)
 
static TupleTableSlotgather_merge_getnext (GatherMergeState *gm_state)
 
static MinimalTuple gm_readnext_tuple (GatherMergeState *gm_state, int nreader, bool nowait, bool *done)
 
static void ExecShutdownGatherMergeWorkers (GatherMergeState *node)
 
static void gather_merge_setup (GatherMergeState *gm_state)
 
static void gather_merge_init (GatherMergeState *gm_state)
 
static void gather_merge_clear_tuples (GatherMergeState *gm_state)
 
static bool gather_merge_readnext (GatherMergeState *gm_state, int reader, bool nowait)
 
static void load_tuple_array (GatherMergeState *gm_state, int reader)
 
GatherMergeStateExecInitGatherMerge (GatherMerge *node, EState *estate, int eflags)
 
void ExecEndGatherMerge (GatherMergeState *node)
 
void ExecShutdownGatherMerge (GatherMergeState *node)
 
void ExecReScanGatherMerge (GatherMergeState *node)
 

Macro Definition Documentation

◆ MAX_TUPLE_STORE

#define MAX_TUPLE_STORE   10

Definition at line 36 of file nodeGatherMerge.c.

Typedef Documentation

◆ GMReaderTupleBuffer

◆ SlotNumber

typedef int32 SlotNumber

Definition at line 747 of file nodeGatherMerge.c.

Function Documentation

◆ ExecEndGatherMerge()

void ExecEndGatherMerge ( GatherMergeState node)

Definition at line 289 of file nodeGatherMerge.c.

290 {
291  ExecEndNode(outerPlanState(node)); /* let children clean up first */
293  ExecFreeExprContext(&node->ps);
294  if (node->ps.ps_ResultTupleSlot)
296 }
void ExecEndNode(PlanState *node)
Definition: execProcnode.c:557
void ExecFreeExprContext(PlanState *planstate)
Definition: execUtils.c:658
#define outerPlanState(node)
Definition: execnodes.h:1131
void ExecShutdownGatherMerge(GatherMergeState *node)
PlanState ps
Definition: execnodes.h:2598
TupleTableSlot * ps_ResultTupleSlot
Definition: execnodes.h:1073
static TupleTableSlot * ExecClearTuple(TupleTableSlot *slot)
Definition: tuptable.h:471

References ExecClearTuple(), ExecEndNode(), ExecFreeExprContext(), ExecShutdownGatherMerge(), outerPlanState, GatherMergeState::ps, and PlanState::ps_ResultTupleSlot.

Referenced by ExecEndNode().

◆ ExecGatherMerge()

static TupleTableSlot * ExecGatherMerge ( PlanState pstate)
static

Definition at line 188 of file nodeGatherMerge.c.

189 {
190  GatherMergeState *node = castNode(GatherMergeState, pstate);
191  TupleTableSlot *slot;
192  ExprContext *econtext;
193 
195 
196  /*
197  * As with Gather, we don't launch workers until this node is actually
198  * executed.
199  */
200  if (!node->initialized)
201  {
202  EState *estate = node->ps.state;
203  GatherMerge *gm = castNode(GatherMerge, node->ps.plan);
204 
205  /*
206  * Sometimes we might have to run without parallelism; but if parallel
207  * mode is active then we can try to fire up some workers.
208  */
209  if (gm->num_workers > 0 && estate->es_use_parallel_mode)
210  {
211  ParallelContext *pcxt;
212 
213  /* Initialize, or re-initialize, shared state needed by workers. */
214  if (!node->pei)
216  estate,
217  gm->initParam,
218  gm->num_workers,
219  node->tuples_needed);
220  else
222  node->pei,
223  gm->initParam);
224 
225  /* Try to launch workers. */
226  pcxt = node->pei->pcxt;
227  LaunchParallelWorkers(pcxt);
228  /* We save # workers launched for the benefit of EXPLAIN */
229  node->nworkers_launched = pcxt->nworkers_launched;
230 
231  /* Set up tuple queue readers to read the results. */
232  if (pcxt->nworkers_launched > 0)
233  {
235  /* Make a working array showing the active readers */
236  node->nreaders = pcxt->nworkers_launched;
237  node->reader = (TupleQueueReader **)
238  palloc(node->nreaders * sizeof(TupleQueueReader *));
239  memcpy(node->reader, node->pei->reader,
240  node->nreaders * sizeof(TupleQueueReader *));
241  }
242  else
243  {
244  /* No workers? Then never mind. */
245  node->nreaders = 0;
246  node->reader = NULL;
247  }
248  }
249 
250  /* allow leader to participate if enabled or no choice */
251  if (parallel_leader_participation || node->nreaders == 0)
252  node->need_to_scan_locally = true;
253  node->initialized = true;
254  }
255 
256  /*
257  * Reset per-tuple memory context to free any expression evaluation
258  * storage allocated in the previous tuple cycle.
259  */
260  econtext = node->ps.ps_ExprContext;
261  ResetExprContext(econtext);
262 
263  /*
264  * Get next tuple, either from one of our workers, or by running the plan
265  * ourselves.
266  */
267  slot = gather_merge_getnext(node);
268  if (TupIsNull(slot))
269  return NULL;
270 
271  /* If no projection is required, we're done. */
272  if (node->ps.ps_ProjInfo == NULL)
273  return slot;
274 
275  /*
276  * Form the result tuple using ExecProject(), and return it.
277  */
278  econtext->ecxt_outertuple = slot;
279  return ExecProject(node->ps.ps_ProjInfo);
280 }
void LaunchParallelWorkers(ParallelContext *pcxt)
Definition: parallel.c:550
ParallelExecutorInfo * ExecInitParallelPlan(PlanState *planstate, EState *estate, Bitmapset *sendParams, int nworkers, int64 tuples_needed)
Definition: execParallel.c:590
void ExecParallelReinitialize(PlanState *planstate, ParallelExecutorInfo *pei, Bitmapset *sendParams)
Definition: execParallel.c:900
void ExecParallelCreateReaders(ParallelExecutorInfo *pei)
Definition: execParallel.c:874
static TupleTableSlot * ExecProject(ProjectionInfo *projInfo)
Definition: executor.h:364
#define ResetExprContext(econtext)
Definition: executor.h:532
void * palloc(Size size)
Definition: mcxt.c:1210
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:121
static TupleTableSlot * gather_merge_getnext(GatherMergeState *gm_state)
#define castNode(_type_, nodeptr)
Definition: nodes.h:197
bool parallel_leader_participation
Definition: planner.c:74
bool es_use_parallel_mode
Definition: execnodes.h:691
TupleTableSlot * ecxt_outertuple
Definition: execnodes.h:253
struct ParallelExecutorInfo * pei
Definition: execnodes.h:2607
struct TupleQueueReader ** reader
Definition: execnodes.h:2613
bool need_to_scan_locally
Definition: execnodes.h:2601
Bitmapset * initParam
Definition: plannodes.h:1187
int num_workers
Definition: plannodes.h:1161
int nworkers_launched
Definition: parallel.h:38
ParallelContext * pcxt
Definition: execParallel.h:27
struct TupleQueueReader ** reader
Definition: execParallel.h:37
Plan * plan
Definition: execnodes.h:1035
EState * state
Definition: execnodes.h:1037
ExprContext * ps_ExprContext
Definition: execnodes.h:1074
ProjectionInfo * ps_ProjInfo
Definition: execnodes.h:1075
#define TupIsNull(slot)
Definition: tuptable.h:300

References castNode, CHECK_FOR_INTERRUPTS, ExprContext::ecxt_outertuple, EState::es_use_parallel_mode, ExecInitParallelPlan(), ExecParallelCreateReaders(), ExecParallelReinitialize(), ExecProject(), gather_merge_getnext(), GatherMergeState::initialized, GatherMerge::initParam, LaunchParallelWorkers(), GatherMergeState::need_to_scan_locally, GatherMergeState::nreaders, GatherMerge::num_workers, ParallelContext::nworkers_launched, GatherMergeState::nworkers_launched, outerPlanState, palloc(), parallel_leader_participation, ParallelExecutorInfo::pcxt, GatherMergeState::pei, PlanState::plan, GatherMergeState::ps, PlanState::ps_ExprContext, PlanState::ps_ProjInfo, ParallelExecutorInfo::reader, GatherMergeState::reader, ResetExprContext, PlanState::state, TupIsNull, and GatherMergeState::tuples_needed.

Referenced by ExecInitGatherMerge().

◆ ExecInitGatherMerge()

GatherMergeState* ExecInitGatherMerge ( GatherMerge node,
EState estate,
int  eflags 
)

Definition at line 72 of file nodeGatherMerge.c.

73 {
74  GatherMergeState *gm_state;
75  Plan *outerNode;
76  TupleDesc tupDesc;
77 
78  /* Gather merge node doesn't have innerPlan node. */
79  Assert(innerPlan(node) == NULL);
80 
81  /*
82  * create state structure
83  */
84  gm_state = makeNode(GatherMergeState);
85  gm_state->ps.plan = (Plan *) node;
86  gm_state->ps.state = estate;
87  gm_state->ps.ExecProcNode = ExecGatherMerge;
88 
89  gm_state->initialized = false;
90  gm_state->gm_initialized = false;
91  gm_state->tuples_needed = -1;
92 
93  /*
94  * Miscellaneous initialization
95  *
96  * create expression context for node
97  */
98  ExecAssignExprContext(estate, &gm_state->ps);
99 
100  /*
101  * GatherMerge doesn't support checking a qual (it's always more efficient
102  * to do it in the child node).
103  */
104  Assert(!node->plan.qual);
105 
106  /*
107  * now initialize outer plan
108  */
109  outerNode = outerPlan(node);
110  outerPlanState(gm_state) = ExecInitNode(outerNode, estate, eflags);
111 
112  /*
113  * Leader may access ExecProcNode result directly (if
114  * need_to_scan_locally), or from workers via tuple queue. So we can't
115  * trivially rely on the slot type being fixed for expressions evaluated
116  * within this node.
117  */
118  gm_state->ps.outeropsset = true;
119  gm_state->ps.outeropsfixed = false;
120 
121  /*
122  * Store the tuple descriptor into gather merge state, so we can use it
123  * while initializing the gather merge slots.
124  */
125  tupDesc = ExecGetResultType(outerPlanState(gm_state));
126  gm_state->tupDesc = tupDesc;
127 
128  /*
129  * Initialize result type and projection.
130  */
131  ExecInitResultTypeTL(&gm_state->ps);
132  ExecConditionalAssignProjectionInfo(&gm_state->ps, tupDesc, OUTER_VAR);
133 
134  /*
135  * Without projections result slot type is not trivially known, see
136  * comment above.
137  */
138  if (gm_state->ps.ps_ProjInfo == NULL)
139  {
140  gm_state->ps.resultopsset = true;
141  gm_state->ps.resultopsfixed = false;
142  }
143 
144  /*
145  * initialize sort-key information
146  */
147  if (node->numCols)
148  {
149  int i;
150 
151  gm_state->gm_nkeys = node->numCols;
152  gm_state->gm_sortkeys =
153  palloc0(sizeof(SortSupportData) * node->numCols);
154 
155  for (i = 0; i < node->numCols; i++)
156  {
157  SortSupport sortKey = gm_state->gm_sortkeys + i;
158 
159  sortKey->ssup_cxt = CurrentMemoryContext;
160  sortKey->ssup_collation = node->collations[i];
161  sortKey->ssup_nulls_first = node->nullsFirst[i];
162  sortKey->ssup_attno = node->sortColIdx[i];
163 
164  /*
165  * We don't perform abbreviated key conversion here, for the same
166  * reasons that it isn't used in MergeAppend
167  */
168  sortKey->abbreviate = false;
169 
170  PrepareSortSupportFromOrderingOp(node->sortOperators[i], sortKey);
171  }
172  }
173 
174  /* Now allocate the workspace for gather merge */
175  gather_merge_setup(gm_state);
176 
177  return gm_state;
178 }
PlanState * ExecInitNode(Plan *node, EState *estate, int eflags)
Definition: execProcnode.c:142
void ExecInitResultTypeTL(PlanState *planstate)
Definition: execTuples.c:1755
TupleDesc ExecGetResultType(PlanState *planstate)
Definition: execUtils.c:498
void ExecAssignExprContext(EState *estate, PlanState *planstate)
Definition: execUtils.c:488
void ExecConditionalAssignProjectionInfo(PlanState *planstate, TupleDesc inputDesc, int varno)
Definition: execUtils.c:563
int i
Definition: isn.c:73
Assert(fmt[strlen(fmt) - 1] !='\n')
void * palloc0(Size size)
Definition: mcxt.c:1241
MemoryContext CurrentMemoryContext
Definition: mcxt.c:135
static void gather_merge_setup(GatherMergeState *gm_state)
static TupleTableSlot * ExecGatherMerge(PlanState *pstate)
#define makeNode(_type_)
Definition: nodes.h:176
#define innerPlan(node)
Definition: plannodes.h:185
#define outerPlan(node)
Definition: plannodes.h:186
#define OUTER_VAR
Definition: primnodes.h:215
void PrepareSortSupportFromOrderingOp(Oid orderingOp, SortSupport ssup)
Definition: sortsupport.c:135
TupleDesc tupDesc
Definition: execnodes.h:2604
SortSupport gm_sortkeys
Definition: execnodes.h:2606
bool outeropsset
Definition: execnodes.h:1118
bool resultopsset
Definition: execnodes.h:1120
bool outeropsfixed
Definition: execnodes.h:1114
bool resultopsfixed
Definition: execnodes.h:1116
ExecProcNodeMtd ExecProcNode
Definition: execnodes.h:1041
List * qual
Definition: plannodes.h:157
AttrNumber ssup_attno
Definition: sortsupport.h:81
bool ssup_nulls_first
Definition: sortsupport.h:75
MemoryContext ssup_cxt
Definition: sortsupport.h:66

References SortSupportData::abbreviate, Assert(), CurrentMemoryContext, ExecAssignExprContext(), ExecConditionalAssignProjectionInfo(), ExecGatherMerge(), ExecGetResultType(), ExecInitNode(), ExecInitResultTypeTL(), PlanState::ExecProcNode, gather_merge_setup(), GatherMergeState::gm_initialized, GatherMergeState::gm_nkeys, GatherMergeState::gm_sortkeys, i, GatherMergeState::initialized, innerPlan, makeNode, GatherMerge::numCols, OUTER_VAR, PlanState::outeropsfixed, PlanState::outeropsset, outerPlan, outerPlanState, palloc0(), PlanState::plan, GatherMerge::plan, PrepareSortSupportFromOrderingOp(), GatherMergeState::ps, PlanState::ps_ProjInfo, Plan::qual, PlanState::resultopsfixed, PlanState::resultopsset, SortSupportData::ssup_attno, SortSupportData::ssup_collation, SortSupportData::ssup_cxt, SortSupportData::ssup_nulls_first, PlanState::state, GatherMergeState::tupDesc, and GatherMergeState::tuples_needed.

Referenced by ExecInitNode().

◆ ExecReScanGatherMerge()

void ExecReScanGatherMerge ( GatherMergeState node)

Definition at line 342 of file nodeGatherMerge.c.

343 {
344  GatherMerge *gm = (GatherMerge *) node->ps.plan;
346 
347  /* Make sure any existing workers are gracefully shut down */
349 
350  /* Free any unused tuples, so we don't leak memory across rescans */
352 
353  /* Mark node so that shared state will be rebuilt at next call */
354  node->initialized = false;
355  node->gm_initialized = false;
356 
357  /*
358  * Set child node's chgParam to tell it that the next scan might deliver a
359  * different set of rows within the leader process. (The overall rowset
360  * shouldn't change, but the leader process's subset might; hence nodes
361  * between here and the parallel table scan node mustn't optimize on the
362  * assumption of an unchanging rowset.)
363  */
364  if (gm->rescan_param >= 0)
365  outerPlan->chgParam = bms_add_member(outerPlan->chgParam,
366  gm->rescan_param);
367 
368  /*
369  * If chgParam of subnode is not null then plan will be re-scanned by
370  * first ExecProcNode. Note: because this does nothing if we have a
371  * rescan_param, it's currently guaranteed that parallel-aware child nodes
372  * will not see a ReScan call until after they get a ReInitializeDSM call.
373  * That ordering might not be something to rely on, though. A good rule
374  * of thumb is that ReInitializeDSM should reset only shared state, ReScan
375  * should reset only local state, and anything that depends on both of
376  * those steps being finished must wait until the first ExecProcNode call.
377  */
378  if (outerPlan->chgParam == NULL)
380 }
Bitmapset * bms_add_member(Bitmapset *a, int x)
Definition: bitmapset.c:755
void ExecReScan(PlanState *node)
Definition: execAmi.c:78
static void gather_merge_clear_tuples(GatherMergeState *gm_state)
static void ExecShutdownGatherMergeWorkers(GatherMergeState *node)
int rescan_param
Definition: plannodes.h:1164

References bms_add_member(), ExecReScan(), ExecShutdownGatherMergeWorkers(), gather_merge_clear_tuples(), GatherMergeState::gm_initialized, GatherMergeState::initialized, outerPlan, outerPlanState, PlanState::plan, GatherMergeState::ps, and GatherMerge::rescan_param.

Referenced by ExecReScan().

◆ ExecShutdownGatherMerge()

void ExecShutdownGatherMerge ( GatherMergeState node)

Definition at line 305 of file nodeGatherMerge.c.

306 {
308 
309  /* Now destroy the parallel context. */
310  if (node->pei != NULL)
311  {
312  ExecParallelCleanup(node->pei);
313  node->pei = NULL;
314  }
315 }
void ExecParallelCleanup(ParallelExecutorInfo *pei)

References ExecParallelCleanup(), ExecShutdownGatherMergeWorkers(), and GatherMergeState::pei.

Referenced by ExecEndGatherMerge(), and ExecShutdownNode_walker().

◆ ExecShutdownGatherMergeWorkers()

static void ExecShutdownGatherMergeWorkers ( GatherMergeState node)
static

Definition at line 324 of file nodeGatherMerge.c.

325 {
326  if (node->pei != NULL)
327  ExecParallelFinish(node->pei);
328 
329  /* Flush local copy of reader array */
330  if (node->reader)
331  pfree(node->reader);
332  node->reader = NULL;
333 }
void ExecParallelFinish(ParallelExecutorInfo *pei)
void pfree(void *pointer)
Definition: mcxt.c:1436

References ExecParallelFinish(), GatherMergeState::pei, pfree(), and GatherMergeState::reader.

Referenced by ExecReScanGatherMerge(), and ExecShutdownGatherMerge().

◆ gather_merge_clear_tuples()

static void gather_merge_clear_tuples ( GatherMergeState gm_state)
static

Definition at line 527 of file nodeGatherMerge.c.

528 {
529  int i;
530 
531  for (i = 0; i < gm_state->nreaders; i++)
532  {
533  GMReaderTupleBuffer *tuple_buffer = &gm_state->gm_tuple_buffers[i];
534 
535  while (tuple_buffer->readCounter < tuple_buffer->nTuples)
536  pfree(tuple_buffer->tuple[tuple_buffer->readCounter++]);
537 
538  ExecClearTuple(gm_state->gm_slots[i + 1]);
539  }
540 }
MinimalTuple * tuple
struct GMReaderTupleBuffer * gm_tuple_buffers
Definition: execnodes.h:2614
TupleTableSlot ** gm_slots
Definition: execnodes.h:2612

References ExecClearTuple(), GatherMergeState::gm_slots, GatherMergeState::gm_tuple_buffers, i, GatherMergeState::nreaders, GMReaderTupleBuffer::nTuples, pfree(), GMReaderTupleBuffer::readCounter, and GMReaderTupleBuffer::tuple.

Referenced by ExecReScanGatherMerge(), and gather_merge_getnext().

◆ gather_merge_getnext()

static TupleTableSlot * gather_merge_getnext ( GatherMergeState gm_state)
static

Definition at line 548 of file nodeGatherMerge.c.

549 {
550  int i;
551 
552  if (!gm_state->gm_initialized)
553  {
554  /*
555  * First time through: pull the first tuple from each participant, and
556  * set up the heap.
557  */
558  gather_merge_init(gm_state);
559  }
560  else
561  {
562  /*
563  * Otherwise, pull the next tuple from whichever participant we
564  * returned from last time, and reinsert that participant's index into
565  * the heap, because it might now compare differently against the
566  * other elements of the heap.
567  */
568  i = DatumGetInt32(binaryheap_first(gm_state->gm_heap));
569 
570  if (gather_merge_readnext(gm_state, i, false))
572  else
573  {
574  /* reader exhausted, remove it from heap */
575  (void) binaryheap_remove_first(gm_state->gm_heap);
576  }
577  }
578 
579  if (binaryheap_empty(gm_state->gm_heap))
580  {
581  /* All the queues are exhausted, and so is the heap */
582  gather_merge_clear_tuples(gm_state);
583  return NULL;
584  }
585  else
586  {
587  /* Return next tuple from whichever participant has the leading one */
588  i = DatumGetInt32(binaryheap_first(gm_state->gm_heap));
589  return gm_state->gm_slots[i];
590  }
591 }
Datum binaryheap_remove_first(binaryheap *heap)
Definition: binaryheap.c:173
void binaryheap_replace_first(binaryheap *heap, Datum d)
Definition: binaryheap.c:207
Datum binaryheap_first(binaryheap *heap)
Definition: binaryheap.c:158
#define binaryheap_empty(h)
Definition: binaryheap.h:52
static void gather_merge_init(GatherMergeState *gm_state)
static bool gather_merge_readnext(GatherMergeState *gm_state, int reader, bool nowait)
static Datum Int32GetDatum(int32 X)
Definition: postgres.h:212
static int32 DatumGetInt32(Datum X)
Definition: postgres.h:202
struct binaryheap * gm_heap
Definition: execnodes.h:2615

References binaryheap_empty, binaryheap_first(), binaryheap_remove_first(), binaryheap_replace_first(), DatumGetInt32(), gather_merge_clear_tuples(), gather_merge_init(), gather_merge_readnext(), GatherMergeState::gm_heap, GatherMergeState::gm_initialized, GatherMergeState::gm_slots, i, and Int32GetDatum().

Referenced by ExecGatherMerge().

◆ gather_merge_init()

static void gather_merge_init ( GatherMergeState gm_state)
static

Definition at line 444 of file nodeGatherMerge.c.

445 {
446  int nreaders = gm_state->nreaders;
447  bool nowait = true;
448  int i;
449 
450  /* Assert that gather_merge_setup made enough space */
451  Assert(nreaders <= castNode(GatherMerge, gm_state->ps.plan)->num_workers);
452 
453  /* Reset leader's tuple slot to empty */
454  gm_state->gm_slots[0] = NULL;
455 
456  /* Reset the tuple slot and tuple array for each worker */
457  for (i = 0; i < nreaders; i++)
458  {
459  /* Reset tuple array to empty */
460  gm_state->gm_tuple_buffers[i].nTuples = 0;
461  gm_state->gm_tuple_buffers[i].readCounter = 0;
462  /* Reset done flag to not-done */
463  gm_state->gm_tuple_buffers[i].done = false;
464  /* Ensure output slot is empty */
465  ExecClearTuple(gm_state->gm_slots[i + 1]);
466  }
467 
468  /* Reset binary heap to empty */
469  binaryheap_reset(gm_state->gm_heap);
470 
471  /*
472  * First, try to read a tuple from each worker (including leader) in
473  * nowait mode. After this, if not all workers were able to produce a
474  * tuple (or a "done" indication), then re-read from remaining workers,
475  * this time using wait mode. Add all live readers (those producing at
476  * least one tuple) to the heap.
477  */
478 reread:
479  for (i = 0; i <= nreaders; i++)
480  {
482 
483  /* skip this source if already known done */
484  if ((i == 0) ? gm_state->need_to_scan_locally :
485  !gm_state->gm_tuple_buffers[i - 1].done)
486  {
487  if (TupIsNull(gm_state->gm_slots[i]))
488  {
489  /* Don't have a tuple yet, try to get one */
490  if (gather_merge_readnext(gm_state, i, nowait))
492  Int32GetDatum(i));
493  }
494  else
495  {
496  /*
497  * We already got at least one tuple from this worker, but
498  * might as well see if it has any more ready by now.
499  */
500  load_tuple_array(gm_state, i);
501  }
502  }
503  }
504 
505  /* need not recheck leader, since nowait doesn't matter for it */
506  for (i = 1; i <= nreaders; i++)
507  {
508  if (!gm_state->gm_tuple_buffers[i - 1].done &&
509  TupIsNull(gm_state->gm_slots[i]))
510  {
511  nowait = false;
512  goto reread;
513  }
514  }
515 
516  /* Now heapify the heap. */
517  binaryheap_build(gm_state->gm_heap);
518 
519  gm_state->gm_initialized = true;
520 }
void binaryheap_build(binaryheap *heap)
Definition: binaryheap.c:125
void binaryheap_add_unordered(binaryheap *heap, Datum d)
Definition: binaryheap.c:109
void binaryheap_reset(binaryheap *heap)
Definition: binaryheap.c:56
static void load_tuple_array(GatherMergeState *gm_state, int reader)

References Assert(), binaryheap_add_unordered(), binaryheap_build(), binaryheap_reset(), castNode, CHECK_FOR_INTERRUPTS, GMReaderTupleBuffer::done, ExecClearTuple(), gather_merge_readnext(), GatherMergeState::gm_heap, GatherMergeState::gm_initialized, GatherMergeState::gm_slots, GatherMergeState::gm_tuple_buffers, i, Int32GetDatum(), load_tuple_array(), GatherMergeState::need_to_scan_locally, GatherMergeState::nreaders, GMReaderTupleBuffer::nTuples, PlanState::plan, GatherMergeState::ps, GMReaderTupleBuffer::readCounter, and TupIsNull.

Referenced by gather_merge_getnext().

◆ gather_merge_readnext()

static bool gather_merge_readnext ( GatherMergeState gm_state,
int  reader,
bool  nowait 
)
static

Definition at line 637 of file nodeGatherMerge.c.

638 {
639  GMReaderTupleBuffer *tuple_buffer;
640  MinimalTuple tup;
641 
642  /*
643  * If we're being asked to generate a tuple from the leader, then we just
644  * call ExecProcNode as normal to produce one.
645  */
646  if (reader == 0)
647  {
648  if (gm_state->need_to_scan_locally)
649  {
650  PlanState *outerPlan = outerPlanState(gm_state);
651  TupleTableSlot *outerTupleSlot;
652  EState *estate = gm_state->ps.state;
653 
654  /* Install our DSA area while executing the plan. */
655  estate->es_query_dsa = gm_state->pei ? gm_state->pei->area : NULL;
656  outerTupleSlot = ExecProcNode(outerPlan);
657  estate->es_query_dsa = NULL;
658 
659  if (!TupIsNull(outerTupleSlot))
660  {
661  gm_state->gm_slots[0] = outerTupleSlot;
662  return true;
663  }
664  /* need_to_scan_locally serves as "done" flag for leader */
665  gm_state->need_to_scan_locally = false;
666  }
667  return false;
668  }
669 
670  /* Otherwise, check the state of the relevant tuple buffer. */
671  tuple_buffer = &gm_state->gm_tuple_buffers[reader - 1];
672 
673  if (tuple_buffer->nTuples > tuple_buffer->readCounter)
674  {
675  /* Return any tuple previously read that is still buffered. */
676  tup = tuple_buffer->tuple[tuple_buffer->readCounter++];
677  }
678  else if (tuple_buffer->done)
679  {
680  /* Reader is known to be exhausted. */
681  return false;
682  }
683  else
684  {
685  /* Read and buffer next tuple. */
686  tup = gm_readnext_tuple(gm_state,
687  reader,
688  nowait,
689  &tuple_buffer->done);
690  if (!tup)
691  return false;
692 
693  /*
694  * Attempt to read more tuples in nowait mode and store them in the
695  * pending-tuple array for the reader.
696  */
697  load_tuple_array(gm_state, reader);
698  }
699 
700  Assert(tup);
701 
702  /* Build the TupleTableSlot for the given tuple */
703  ExecStoreMinimalTuple(tup, /* tuple to store */
704  gm_state->gm_slots[reader], /* slot in which to
705  * store the tuple */
706  true); /* pfree tuple when done with it */
707 
708  return true;
709 }
TupleTableSlot * ExecStoreMinimalTuple(MinimalTuple mtup, TupleTableSlot *slot, bool shouldFree)
Definition: execTuples.c:1446
static TupleTableSlot * ExecProcNode(PlanState *node)
Definition: executor.h:257
static MinimalTuple gm_readnext_tuple(GatherMergeState *gm_state, int nreader, bool nowait, bool *done)
struct dsa_area * es_query_dsa
Definition: execnodes.h:694

References ParallelExecutorInfo::area, Assert(), GMReaderTupleBuffer::done, EState::es_query_dsa, ExecProcNode(), ExecStoreMinimalTuple(), gm_readnext_tuple(), GatherMergeState::gm_slots, GatherMergeState::gm_tuple_buffers, load_tuple_array(), GatherMergeState::need_to_scan_locally, GMReaderTupleBuffer::nTuples, outerPlan, outerPlanState, GatherMergeState::pei, GatherMergeState::ps, GMReaderTupleBuffer::readCounter, PlanState::state, TupIsNull, and GMReaderTupleBuffer::tuple.

Referenced by gather_merge_getnext(), and gather_merge_init().

◆ gather_merge_setup()

static void gather_merge_setup ( GatherMergeState gm_state)
static

Definition at line 396 of file nodeGatherMerge.c.

397 {
398  GatherMerge *gm = castNode(GatherMerge, gm_state->ps.plan);
399  int nreaders = gm->num_workers;
400  int i;
401 
402  /*
403  * Allocate gm_slots for the number of workers + one more slot for leader.
404  * Slot 0 is always for the leader. Leader always calls ExecProcNode() to
405  * read the tuple, and then stores it directly into its gm_slots entry.
406  * For other slots, code below will call ExecInitExtraTupleSlot() to
407  * create a slot for the worker's results. Note that during any single
408  * scan, we might have fewer than num_workers available workers, in which
409  * case the extra array entries go unused.
410  */
411  gm_state->gm_slots = (TupleTableSlot **)
412  palloc0((nreaders + 1) * sizeof(TupleTableSlot *));
413 
414  /* Allocate the tuple slot and tuple array for each worker */
415  gm_state->gm_tuple_buffers = (GMReaderTupleBuffer *)
416  palloc0(nreaders * sizeof(GMReaderTupleBuffer));
417 
418  for (i = 0; i < nreaders; i++)
419  {
420  /* Allocate the tuple array with length MAX_TUPLE_STORE */
421  gm_state->gm_tuple_buffers[i].tuple =
423 
424  /* Initialize tuple slot for worker */
425  gm_state->gm_slots[i + 1] =
426  ExecInitExtraTupleSlot(gm_state->ps.state, gm_state->tupDesc,
428  }
429 
430  /* Allocate the resources for the merge */
431  gm_state->gm_heap = binaryheap_allocate(nreaders + 1,
433  gm_state);
434 }
binaryheap * binaryheap_allocate(int capacity, binaryheap_comparator compare, void *arg)
Definition: binaryheap.c:32
TupleTableSlot * ExecInitExtraTupleSlot(EState *estate, TupleDesc tupledesc, const TupleTableSlotOps *tts_ops)
Definition: execTuples.c:1831
const TupleTableSlotOps TTSOpsMinimalTuple
Definition: execTuples.c:85
static int32 heap_compare_slots(Datum a, Datum b, void *arg)
#define MAX_TUPLE_STORE

References binaryheap_allocate(), castNode, ExecInitExtraTupleSlot(), GatherMergeState::gm_heap, GatherMergeState::gm_slots, GatherMergeState::gm_tuple_buffers, heap_compare_slots(), i, MAX_TUPLE_STORE, GatherMerge::num_workers, palloc0(), PlanState::plan, GatherMergeState::ps, PlanState::state, TTSOpsMinimalTuple, GatherMergeState::tupDesc, and GMReaderTupleBuffer::tuple.

Referenced by ExecInitGatherMerge().

◆ gm_readnext_tuple()

static MinimalTuple gm_readnext_tuple ( GatherMergeState gm_state,
int  nreader,
bool  nowait,
bool done 
)
static

Definition at line 715 of file nodeGatherMerge.c.

717 {
718  TupleQueueReader *reader;
719  MinimalTuple tup;
720 
721  /* Check for async events, particularly messages from workers. */
723 
724  /*
725  * Attempt to read a tuple.
726  *
727  * Note that TupleQueueReaderNext will just return NULL for a worker which
728  * fails to initialize. We'll treat that worker as having produced no
729  * tuples; WaitForParallelWorkersToFinish will error out when we get
730  * there.
731  */
732  reader = gm_state->reader[nreader - 1];
733  tup = TupleQueueReaderNext(reader, nowait, done);
734 
735  /*
736  * Since we'll be buffering these across multiple calls, we need to make a
737  * copy.
738  */
739  return tup ? heap_copy_minimal_tuple(tup) : NULL;
740 }
MinimalTuple heap_copy_minimal_tuple(MinimalTuple mtup)
Definition: heaptuple.c:1439
MinimalTuple TupleQueueReaderNext(TupleQueueReader *reader, bool nowait, bool *done)
Definition: tqueue.c:176

References CHECK_FOR_INTERRUPTS, heap_copy_minimal_tuple(), GatherMergeState::reader, and TupleQueueReaderNext().

Referenced by gather_merge_readnext(), and load_tuple_array().

◆ heap_compare_slots()

static int32 heap_compare_slots ( Datum  a,
Datum  b,
void *  arg 
)
static

Definition at line 753 of file nodeGatherMerge.c.

754 {
756  SlotNumber slot1 = DatumGetInt32(a);
757  SlotNumber slot2 = DatumGetInt32(b);
758 
759  TupleTableSlot *s1 = node->gm_slots[slot1];
760  TupleTableSlot *s2 = node->gm_slots[slot2];
761  int nkey;
762 
763  Assert(!TupIsNull(s1));
764  Assert(!TupIsNull(s2));
765 
766  for (nkey = 0; nkey < node->gm_nkeys; nkey++)
767  {
768  SortSupport sortKey = node->gm_sortkeys + nkey;
769  AttrNumber attno = sortKey->ssup_attno;
770  Datum datum1,
771  datum2;
772  bool isNull1,
773  isNull2;
774  int compare;
775 
776  datum1 = slot_getattr(s1, attno, &isNull1);
777  datum2 = slot_getattr(s2, attno, &isNull2);
778 
779  compare = ApplySortComparator(datum1, isNull1,
780  datum2, isNull2,
781  sortKey);
782  if (compare != 0)
783  {
785  return compare;
786  }
787  }
788  return 0;
789 }
int16 AttrNumber
Definition: attnum.h:21
#define INVERT_COMPARE_RESULT(var)
Definition: c.h:1114
static int compare(const void *arg1, const void *arg2)
Definition: geqo_pool.c:145
int b
Definition: isn.c:70
int a
Definition: isn.c:69
int32 SlotNumber
void * arg
uintptr_t Datum
Definition: postgres.h:64
char * s1
char * s2
static int ApplySortComparator(Datum datum1, bool isNull1, Datum datum2, bool isNull2, SortSupport ssup)
Definition: sortsupport.h:200
static Datum slot_getattr(TupleTableSlot *slot, int attnum, bool *isnull)
Definition: tuptable.h:427

References a, ApplySortComparator(), arg, Assert(), b, compare(), DatumGetInt32(), GatherMergeState::gm_nkeys, GatherMergeState::gm_slots, GatherMergeState::gm_sortkeys, INVERT_COMPARE_RESULT, s1, s2, slot_getattr(), SortSupportData::ssup_attno, and TupIsNull.

Referenced by gather_merge_setup().

◆ load_tuple_array()

static void load_tuple_array ( GatherMergeState gm_state,
int  reader 
)
static

Definition at line 598 of file nodeGatherMerge.c.

599 {
600  GMReaderTupleBuffer *tuple_buffer;
601  int i;
602 
603  /* Don't do anything if this is the leader. */
604  if (reader == 0)
605  return;
606 
607  tuple_buffer = &gm_state->gm_tuple_buffers[reader - 1];
608 
609  /* If there's nothing in the array, reset the counters to zero. */
610  if (tuple_buffer->nTuples == tuple_buffer->readCounter)
611  tuple_buffer->nTuples = tuple_buffer->readCounter = 0;
612 
613  /* Try to fill additional slots in the array. */
614  for (i = tuple_buffer->nTuples; i < MAX_TUPLE_STORE; i++)
615  {
616  MinimalTuple tuple;
617 
618  tuple = gm_readnext_tuple(gm_state,
619  reader,
620  true,
621  &tuple_buffer->done);
622  if (!tuple)
623  break;
624  tuple_buffer->tuple[i] = tuple;
625  tuple_buffer->nTuples++;
626  }
627 }

References GMReaderTupleBuffer::done, gm_readnext_tuple(), GatherMergeState::gm_tuple_buffers, i, MAX_TUPLE_STORE, GMReaderTupleBuffer::nTuples, GMReaderTupleBuffer::readCounter, and GMReaderTupleBuffer::tuple.

Referenced by gather_merge_init(), and gather_merge_readnext().