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nodeBitmapIndexscan.c
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1 /*-------------------------------------------------------------------------
2  *
3  * nodeBitmapIndexscan.c
4  * Routines to support bitmapped index scans of relations
5  *
6  * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
7  * Portions Copyright (c) 1994, Regents of the University of California
8  *
9  *
10  * IDENTIFICATION
11  * src/backend/executor/nodeBitmapIndexscan.c
12  *
13  *-------------------------------------------------------------------------
14  */
15 /*
16  * INTERFACE ROUTINES
17  * MultiExecBitmapIndexScan scans a relation using index.
18  * ExecInitBitmapIndexScan creates and initializes state info.
19  * ExecReScanBitmapIndexScan prepares to rescan the plan.
20  * ExecEndBitmapIndexScan releases all storage.
21  */
22 #include "postgres.h"
23 
24 #include "access/genam.h"
25 #include "executor/execdebug.h"
27 #include "executor/nodeIndexscan.h"
28 #include "miscadmin.h"
29 #include "utils/memutils.h"
30 
31 
32 /* ----------------------------------------------------------------
33  * ExecBitmapIndexScan
34  *
35  * stub for pro forma compliance
36  * ----------------------------------------------------------------
37  */
38 static TupleTableSlot *
40 {
41  elog(ERROR, "BitmapIndexScan node does not support ExecProcNode call convention");
42  return NULL;
43 }
44 
45 /* ----------------------------------------------------------------
46  * MultiExecBitmapIndexScan(node)
47  * ----------------------------------------------------------------
48  */
49 Node *
51 {
52  TIDBitmap *tbm;
53  IndexScanDesc scandesc;
54  double nTuples = 0;
55  bool doscan;
56 
57  /* must provide our own instrumentation support */
58  if (node->ss.ps.instrument)
60 
61  /*
62  * extract necessary information from index scan node
63  */
64  scandesc = node->biss_ScanDesc;
65 
66  /*
67  * If we have runtime keys and they've not already been set up, do it now.
68  * Array keys are also treated as runtime keys; note that if ExecReScan
69  * returns with biss_RuntimeKeysReady still false, then there is an empty
70  * array key so we should do nothing.
71  */
72  if (!node->biss_RuntimeKeysReady &&
73  (node->biss_NumRuntimeKeys != 0 || node->biss_NumArrayKeys != 0))
74  {
75  ExecReScan((PlanState *) node);
76  doscan = node->biss_RuntimeKeysReady;
77  }
78  else
79  doscan = true;
80 
81  /*
82  * Prepare the result bitmap. Normally we just create a new one to pass
83  * back; however, our parent node is allowed to store a pre-made one into
84  * node->biss_result, in which case we just OR our tuple IDs into the
85  * existing bitmap. (This saves needing explicit UNION steps.)
86  */
87  if (node->biss_result)
88  {
89  tbm = node->biss_result;
90  node->biss_result = NULL; /* reset for next time */
91  }
92  else
93  {
94  /* XXX should we use less than work_mem for this? */
95  tbm = tbm_create(work_mem * 1024L,
96  ((BitmapIndexScan *) node->ss.ps.plan)->isshared ?
97  node->ss.ps.state->es_query_dsa : NULL);
98  }
99 
100  /*
101  * Get TIDs from index and insert into bitmap
102  */
103  while (doscan)
104  {
105  nTuples += (double) index_getbitmap(scandesc, tbm);
106 
108 
110  node->biss_NumArrayKeys);
111  if (doscan) /* reset index scan */
113  node->biss_ScanKeys, node->biss_NumScanKeys,
114  NULL, 0);
115  }
116 
117  /* must provide our own instrumentation support */
118  if (node->ss.ps.instrument)
119  InstrStopNode(node->ss.ps.instrument, nTuples);
120 
121  return (Node *) tbm;
122 }
123 
124 /* ----------------------------------------------------------------
125  * ExecReScanBitmapIndexScan(node)
126  *
127  * Recalculates the values of any scan keys whose value depends on
128  * information known at runtime, then rescans the indexed relation.
129  * ----------------------------------------------------------------
130  */
131 void
133 {
134  ExprContext *econtext = node->biss_RuntimeContext;
135 
136  /*
137  * Reset the runtime-key context so we don't leak memory as each outer
138  * tuple is scanned. Note this assumes that we will recalculate *all*
139  * runtime keys on each call.
140  */
141  if (econtext)
142  ResetExprContext(econtext);
143 
144  /*
145  * If we are doing runtime key calculations (ie, any of the index key
146  * values weren't simple Consts), compute the new key values.
147  *
148  * Array keys are also treated as runtime keys; note that if we return
149  * with biss_RuntimeKeysReady still false, then there is an empty array
150  * key so no index scan is needed.
151  */
152  if (node->biss_NumRuntimeKeys != 0)
153  ExecIndexEvalRuntimeKeys(econtext,
154  node->biss_RuntimeKeys,
155  node->biss_NumRuntimeKeys);
156  if (node->biss_NumArrayKeys != 0)
157  node->biss_RuntimeKeysReady =
158  ExecIndexEvalArrayKeys(econtext,
159  node->biss_ArrayKeys,
160  node->biss_NumArrayKeys);
161  else
162  node->biss_RuntimeKeysReady = true;
163 
164  /* reset index scan */
165  if (node->biss_RuntimeKeysReady)
167  node->biss_ScanKeys, node->biss_NumScanKeys,
168  NULL, 0);
169 }
170 
171 /* ----------------------------------------------------------------
172  * ExecEndBitmapIndexScan
173  * ----------------------------------------------------------------
174  */
175 void
177 {
178  Relation indexRelationDesc;
179  IndexScanDesc indexScanDesc;
180 
181  /*
182  * extract information from the node
183  */
184  indexRelationDesc = node->biss_RelationDesc;
185  indexScanDesc = node->biss_ScanDesc;
186 
187  /*
188  * close the index relation (no-op if we didn't open it)
189  */
190  if (indexScanDesc)
191  index_endscan(indexScanDesc);
192  if (indexRelationDesc)
193  index_close(indexRelationDesc, NoLock);
194 }
195 
196 /* ----------------------------------------------------------------
197  * ExecInitBitmapIndexScan
198  *
199  * Initializes the index scan's state information.
200  * ----------------------------------------------------------------
201  */
203 ExecInitBitmapIndexScan(BitmapIndexScan *node, EState *estate, int eflags)
204 {
205  BitmapIndexScanState *indexstate;
206  LOCKMODE lockmode;
207 
208  /* check for unsupported flags */
209  Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
210 
211  /*
212  * create state structure
213  */
214  indexstate = makeNode(BitmapIndexScanState);
215  indexstate->ss.ps.plan = (Plan *) node;
216  indexstate->ss.ps.state = estate;
217  indexstate->ss.ps.ExecProcNode = ExecBitmapIndexScan;
218 
219  /* normally we don't make the result bitmap till runtime */
220  indexstate->biss_result = NULL;
221 
222  /*
223  * We do not open or lock the base relation here. We assume that an
224  * ancestor BitmapHeapScan node is holding AccessShareLock (or better) on
225  * the heap relation throughout the execution of the plan tree.
226  */
227 
228  indexstate->ss.ss_currentRelation = NULL;
229  indexstate->ss.ss_currentScanDesc = NULL;
230 
231  /*
232  * Miscellaneous initialization
233  *
234  * We do not need a standard exprcontext for this node, though we may
235  * decide below to create a runtime-key exprcontext
236  */
237 
238  /*
239  * initialize child expressions
240  *
241  * We don't need to initialize targetlist or qual since neither are used.
242  *
243  * Note: we don't initialize all of the indexqual expression, only the
244  * sub-parts corresponding to runtime keys (see below).
245  */
246 
247  /*
248  * If we are just doing EXPLAIN (ie, aren't going to run the plan), stop
249  * here. This allows an index-advisor plugin to EXPLAIN a plan containing
250  * references to nonexistent indexes.
251  */
252  if (eflags & EXEC_FLAG_EXPLAIN_ONLY)
253  return indexstate;
254 
255  /* Open the index relation. */
256  lockmode = exec_rt_fetch(node->scan.scanrelid, estate)->rellockmode;
257  indexstate->biss_RelationDesc = index_open(node->indexid, lockmode);
258 
259  /*
260  * Initialize index-specific scan state
261  */
262  indexstate->biss_RuntimeKeysReady = false;
263  indexstate->biss_RuntimeKeys = NULL;
264  indexstate->biss_NumRuntimeKeys = 0;
265 
266  /*
267  * build the index scan keys from the index qualification
268  */
269  ExecIndexBuildScanKeys((PlanState *) indexstate,
270  indexstate->biss_RelationDesc,
271  node->indexqual,
272  false,
273  &indexstate->biss_ScanKeys,
274  &indexstate->biss_NumScanKeys,
275  &indexstate->biss_RuntimeKeys,
276  &indexstate->biss_NumRuntimeKeys,
277  &indexstate->biss_ArrayKeys,
278  &indexstate->biss_NumArrayKeys);
279 
280  /*
281  * If we have runtime keys or array keys, we need an ExprContext to
282  * evaluate them. We could just create a "standard" plan node exprcontext,
283  * but to keep the code looking similar to nodeIndexscan.c, it seems
284  * better to stick with the approach of using a separate ExprContext.
285  */
286  if (indexstate->biss_NumRuntimeKeys != 0 ||
287  indexstate->biss_NumArrayKeys != 0)
288  {
289  ExprContext *stdecontext = indexstate->ss.ps.ps_ExprContext;
290 
291  ExecAssignExprContext(estate, &indexstate->ss.ps);
292  indexstate->biss_RuntimeContext = indexstate->ss.ps.ps_ExprContext;
293  indexstate->ss.ps.ps_ExprContext = stdecontext;
294  }
295  else
296  {
297  indexstate->biss_RuntimeContext = NULL;
298  }
299 
300  /*
301  * Initialize scan descriptor.
302  */
303  indexstate->biss_ScanDesc =
305  estate->es_snapshot,
306  indexstate->biss_NumScanKeys);
307 
308  /*
309  * If no run-time keys to calculate, go ahead and pass the scankeys to the
310  * index AM.
311  */
312  if (indexstate->biss_NumRuntimeKeys == 0 &&
313  indexstate->biss_NumArrayKeys == 0)
314  index_rescan(indexstate->biss_ScanDesc,
315  indexstate->biss_ScanKeys, indexstate->biss_NumScanKeys,
316  NULL, 0);
317 
318  /*
319  * all done.
320  */
321  return indexstate;
322 }
#define ERROR
Definition: elog.h:39
void ExecReScan(PlanState *node)
Definition: execAmi.c:78
void ExecAssignExprContext(EState *estate, PlanState *planstate)
Definition: execUtils.c:488
#define EXEC_FLAG_BACKWARD
Definition: executor.h:68
static RangeTblEntry * exec_rt_fetch(Index rti, EState *estate)
Definition: executor.h:586
#define ResetExprContext(econtext)
Definition: executor.h:543
#define EXEC_FLAG_EXPLAIN_ONLY
Definition: executor.h:65
#define EXEC_FLAG_MARK
Definition: executor.h:69
int work_mem
Definition: globals.c:128
IndexScanDesc index_beginscan_bitmap(Relation indexRelation, Snapshot snapshot, int nkeys)
Definition: indexam.c:288
void index_close(Relation relation, LOCKMODE lockmode)
Definition: indexam.c:177
void index_endscan(IndexScanDesc scan)
Definition: indexam.c:379
Relation index_open(Oid relationId, LOCKMODE lockmode)
Definition: indexam.c:133
int64 index_getbitmap(IndexScanDesc scan, TIDBitmap *bitmap)
Definition: indexam.c:721
void index_rescan(IndexScanDesc scan, ScanKey keys, int nkeys, ScanKey orderbys, int norderbys)
Definition: indexam.c:353
void InstrStartNode(Instrumentation *instr)
Definition: instrument.c:68
void InstrStopNode(Instrumentation *instr, double nTuples)
Definition: instrument.c:84
Assert(fmt[strlen(fmt) - 1] !='\n')
int LOCKMODE
Definition: lockdefs.h:26
#define NoLock
Definition: lockdefs.h:34
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:122
BitmapIndexScanState * ExecInitBitmapIndexScan(BitmapIndexScan *node, EState *estate, int eflags)
void ExecEndBitmapIndexScan(BitmapIndexScanState *node)
Node * MultiExecBitmapIndexScan(BitmapIndexScanState *node)
static TupleTableSlot * ExecBitmapIndexScan(PlanState *pstate)
void ExecReScanBitmapIndexScan(BitmapIndexScanState *node)
void ExecIndexBuildScanKeys(PlanState *planstate, Relation index, List *quals, bool isorderby, ScanKey *scanKeys, int *numScanKeys, IndexRuntimeKeyInfo **runtimeKeys, int *numRuntimeKeys, IndexArrayKeyInfo **arrayKeys, int *numArrayKeys)
bool ExecIndexEvalArrayKeys(ExprContext *econtext, IndexArrayKeyInfo *arrayKeys, int numArrayKeys)
void ExecIndexEvalRuntimeKeys(ExprContext *econtext, IndexRuntimeKeyInfo *runtimeKeys, int numRuntimeKeys)
bool ExecIndexAdvanceArrayKeys(IndexArrayKeyInfo *arrayKeys, int numArrayKeys)
#define makeNode(_type_)
Definition: nodes.h:155
ExprContext * biss_RuntimeContext
Definition: execnodes.h:1657
IndexArrayKeyInfo * biss_ArrayKeys
Definition: execnodes.h:1654
IndexRuntimeKeyInfo * biss_RuntimeKeys
Definition: execnodes.h:1652
TIDBitmap * biss_result
Definition: execnodes.h:1649
struct ScanKeyData * biss_ScanKeys
Definition: execnodes.h:1650
struct IndexScanDescData * biss_ScanDesc
Definition: execnodes.h:1659
Relation biss_RelationDesc
Definition: execnodes.h:1658
List * indexqual
Definition: plannodes.h:523
struct dsa_area * es_query_dsa
Definition: execnodes.h:702
Snapshot es_snapshot
Definition: execnodes.h:622
Definition: nodes.h:129
Instrumentation * instrument
Definition: execnodes.h:1053
Plan * plan
Definition: execnodes.h:1043
EState * state
Definition: execnodes.h:1045
ExprContext * ps_ExprContext
Definition: execnodes.h:1082
ExecProcNodeMtd ExecProcNode
Definition: execnodes.h:1049
Relation ss_currentRelation
Definition: execnodes.h:1481
PlanState ps
Definition: execnodes.h:1480
struct TableScanDescData * ss_currentScanDesc
Definition: execnodes.h:1482
Index scanrelid
Definition: plannodes.h:387
TIDBitmap * tbm_create(long maxbytes, dsa_area *dsa)
Definition: tidbitmap.c:266