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nodeCustom.c
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1 /* ------------------------------------------------------------------------
2  *
3  * nodeCustom.c
4  * Routines to handle execution of custom scan node
5  *
6  * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
7  * Portions Copyright (c) 1994, Regents of the University of California
8  *
9  * ------------------------------------------------------------------------
10  */
11 #include "postgres.h"
12 
13 #include "access/parallel.h"
14 #include "executor/executor.h"
15 #include "executor/nodeCustom.h"
16 #include "miscadmin.h"
17 #include "nodes/execnodes.h"
18 #include "nodes/extensible.h"
19 #include "nodes/plannodes.h"
20 #include "parser/parsetree.h"
21 #include "utils/hsearch.h"
22 #include "utils/memutils.h"
23 #include "utils/rel.h"
24 
25 static TupleTableSlot *ExecCustomScan(PlanState *pstate);
26 
27 
29 ExecInitCustomScan(CustomScan *cscan, EState *estate, int eflags)
30 {
31  CustomScanState *css;
32  const TupleTableSlotOps *slotOps;
33  Relation scan_rel = NULL;
34  Index scanrelid = cscan->scan.scanrelid;
35  int tlistvarno;
36 
37  /*
38  * Allocate the CustomScanState object. We let the custom scan provider
39  * do the palloc, in case it wants to make a larger object that embeds
40  * CustomScanState as the first field. It must set the node tag and the
41  * methods field correctly at this time. Other standard fields should be
42  * set to zero.
43  */
45  cscan->methods->CreateCustomScanState(cscan));
46 
47  /* ensure flags is filled correctly */
48  css->flags = cscan->flags;
49 
50  /* fill up fields of ScanState */
51  css->ss.ps.plan = &cscan->scan.plan;
52  css->ss.ps.state = estate;
54 
55  /* create expression context for node */
56  ExecAssignExprContext(estate, &css->ss.ps);
57 
58  /*
59  * open the scan relation, if any
60  */
61  if (scanrelid > 0)
62  {
63  scan_rel = ExecOpenScanRelation(estate, scanrelid, eflags);
64  css->ss.ss_currentRelation = scan_rel;
65  }
66 
67  /*
68  * Use a custom slot if specified in CustomScanState or use virtual slot
69  * otherwise.
70  */
71  slotOps = css->slotOps;
72  if (!slotOps)
73  slotOps = &TTSOpsVirtual;
74 
75  /*
76  * Determine the scan tuple type. If the custom scan provider provided a
77  * targetlist describing the scan tuples, use that; else use base
78  * relation's rowtype.
79  */
80  if (cscan->custom_scan_tlist != NIL || scan_rel == NULL)
81  {
82  TupleDesc scan_tupdesc;
83 
84  scan_tupdesc = ExecTypeFromTL(cscan->custom_scan_tlist);
85  ExecInitScanTupleSlot(estate, &css->ss, scan_tupdesc, slotOps);
86  /* Node's targetlist will contain Vars with varno = INDEX_VAR */
87  tlistvarno = INDEX_VAR;
88  }
89  else
90  {
91  ExecInitScanTupleSlot(estate, &css->ss, RelationGetDescr(scan_rel),
92  slotOps);
93  /* Node's targetlist will contain Vars with varno = scanrelid */
94  tlistvarno = scanrelid;
95  }
96 
97  /*
98  * Initialize result slot, type and projection.
99  */
101  ExecAssignScanProjectionInfoWithVarno(&css->ss, tlistvarno);
102 
103  /* initialize child expressions */
104  css->ss.ps.qual =
105  ExecInitQual(cscan->scan.plan.qual, (PlanState *) css);
106 
107  /*
108  * The callback of custom-scan provider applies the final initialization
109  * of the custom-scan-state node according to its logic.
110  */
111  css->methods->BeginCustomScan(css, estate, eflags);
112 
113  return css;
114 }
115 
116 static TupleTableSlot *
118 {
119  CustomScanState *node = castNode(CustomScanState, pstate);
120 
122 
123  Assert(node->methods->ExecCustomScan != NULL);
124  return node->methods->ExecCustomScan(node);
125 }
126 
127 void
129 {
130  Assert(node->methods->EndCustomScan != NULL);
131  node->methods->EndCustomScan(node);
132 
133  /* Free the exprcontext */
134  ExecFreeExprContext(&node->ss.ps);
135 
136  /* Clean out the tuple table */
139 }
140 
141 void
143 {
144  Assert(node->methods->ReScanCustomScan != NULL);
145  node->methods->ReScanCustomScan(node);
146 }
147 
148 void
150 {
151  if (!node->methods->MarkPosCustomScan)
152  ereport(ERROR,
153  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
154  errmsg("custom scan \"%s\" does not support MarkPos",
155  node->methods->CustomName)));
156  node->methods->MarkPosCustomScan(node);
157 }
158 
159 void
161 {
162  if (!node->methods->RestrPosCustomScan)
163  ereport(ERROR,
164  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
165  errmsg("custom scan \"%s\" does not support MarkPos",
166  node->methods->CustomName)));
167  node->methods->RestrPosCustomScan(node);
168 }
169 
170 void
172 {
173  const CustomExecMethods *methods = node->methods;
174 
175  if (methods->EstimateDSMCustomScan)
176  {
177  node->pscan_len = methods->EstimateDSMCustomScan(node, pcxt);
179  shm_toc_estimate_keys(&pcxt->estimator, 1);
180  }
181 }
182 
183 void
185 {
186  const CustomExecMethods *methods = node->methods;
187 
188  if (methods->InitializeDSMCustomScan)
189  {
190  int plan_node_id = node->ss.ps.plan->plan_node_id;
191  void *coordinate;
192 
193  coordinate = shm_toc_allocate(pcxt->toc, node->pscan_len);
194  methods->InitializeDSMCustomScan(node, pcxt, coordinate);
195  shm_toc_insert(pcxt->toc, plan_node_id, coordinate);
196  }
197 }
198 
199 void
201 {
202  const CustomExecMethods *methods = node->methods;
203 
204  if (methods->ReInitializeDSMCustomScan)
205  {
206  int plan_node_id = node->ss.ps.plan->plan_node_id;
207  void *coordinate;
208 
209  coordinate = shm_toc_lookup(pcxt->toc, plan_node_id, false);
210  methods->ReInitializeDSMCustomScan(node, pcxt, coordinate);
211  }
212 }
213 
214 void
216  ParallelWorkerContext *pwcxt)
217 {
218  const CustomExecMethods *methods = node->methods;
219 
220  if (methods->InitializeWorkerCustomScan)
221  {
222  int plan_node_id = node->ss.ps.plan->plan_node_id;
223  void *coordinate;
224 
225  coordinate = shm_toc_lookup(pwcxt->toc, plan_node_id, false);
226  methods->InitializeWorkerCustomScan(node, pwcxt->toc, coordinate);
227  }
228 }
229 
230 void
232 {
233  const CustomExecMethods *methods = node->methods;
234 
235  if (methods->ShutdownCustomScan)
236  methods->ShutdownCustomScan(node);
237 }
unsigned int Index
Definition: c.h:598
int errcode(int sqlerrcode)
Definition: elog.c:858
int errmsg(const char *fmt,...)
Definition: elog.c:1069
#define ERROR
Definition: elog.h:39
#define ereport(elevel,...)
Definition: elog.h:149
ExprState * ExecInitQual(List *qual, PlanState *parent)
Definition: execExpr.c:213
void ExecAssignScanProjectionInfoWithVarno(ScanState *node, int varno)
Definition: execScan.c:285
const TupleTableSlotOps TTSOpsVirtual
Definition: execTuples.c:83
void ExecInitScanTupleSlot(EState *estate, ScanState *scanstate, TupleDesc tupledesc, const TupleTableSlotOps *tts_ops)
Definition: execTuples.c:1811
void ExecInitResultTupleSlotTL(PlanState *planstate, const TupleTableSlotOps *tts_ops)
Definition: execTuples.c:1799
TupleDesc ExecTypeFromTL(List *targetList)
Definition: execTuples.c:1938
void ExecAssignExprContext(EState *estate, PlanState *planstate)
Definition: execUtils.c:488
Relation ExecOpenScanRelation(EState *estate, Index scanrelid, int eflags)
Definition: execUtils.c:728
void ExecFreeExprContext(PlanState *planstate)
Definition: execUtils.c:658
Assert(fmt[strlen(fmt) - 1] !='\n')
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:121
void ExecCustomScanInitializeDSM(CustomScanState *node, ParallelContext *pcxt)
Definition: nodeCustom.c:184
void ExecShutdownCustomScan(CustomScanState *node)
Definition: nodeCustom.c:231
void ExecCustomScanEstimate(CustomScanState *node, ParallelContext *pcxt)
Definition: nodeCustom.c:171
CustomScanState * ExecInitCustomScan(CustomScan *cscan, EState *estate, int eflags)
Definition: nodeCustom.c:29
void ExecCustomRestrPos(CustomScanState *node)
Definition: nodeCustom.c:160
void ExecReScanCustomScan(CustomScanState *node)
Definition: nodeCustom.c:142
void ExecCustomScanReInitializeDSM(CustomScanState *node, ParallelContext *pcxt)
Definition: nodeCustom.c:200
void ExecEndCustomScan(CustomScanState *node)
Definition: nodeCustom.c:128
void ExecCustomScanInitializeWorker(CustomScanState *node, ParallelWorkerContext *pwcxt)
Definition: nodeCustom.c:215
void ExecCustomMarkPos(CustomScanState *node)
Definition: nodeCustom.c:149
static TupleTableSlot * ExecCustomScan(PlanState *pstate)
Definition: nodeCustom.c:117
#define castNode(_type_, nodeptr)
Definition: nodes.h:197
#define NIL
Definition: pg_list.h:68
#define INDEX_VAR
Definition: primnodes.h:216
#define RelationGetDescr(relation)
Definition: rel.h:529
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
void * shm_toc_lookup(shm_toc *toc, uint64 key, bool noError)
Definition: shm_toc.c:232
#define shm_toc_estimate_chunk(e, sz)
Definition: shm_toc.h:51
#define shm_toc_estimate_keys(e, cnt)
Definition: shm_toc.h:53
void(* BeginCustomScan)(CustomScanState *node, EState *estate, int eflags)
Definition: extensible.h:129
TupleTableSlot *(* ExecCustomScan)(CustomScanState *node)
Definition: extensible.h:132
void(* EndCustomScan)(CustomScanState *node)
Definition: extensible.h:133
void(* ShutdownCustomScan)(CustomScanState *node)
Definition: extensible.h:152
const char * CustomName
Definition: extensible.h:126
void(* ReInitializeDSMCustomScan)(CustomScanState *node, ParallelContext *pcxt, void *coordinate)
Definition: extensible.h:146
void(* InitializeDSMCustomScan)(CustomScanState *node, ParallelContext *pcxt, void *coordinate)
Definition: extensible.h:143
void(* RestrPosCustomScan)(CustomScanState *node)
Definition: extensible.h:138
Size(* EstimateDSMCustomScan)(CustomScanState *node, ParallelContext *pcxt)
Definition: extensible.h:141
void(* MarkPosCustomScan)(CustomScanState *node)
Definition: extensible.h:137
void(* InitializeWorkerCustomScan)(CustomScanState *node, shm_toc *toc, void *coordinate)
Definition: extensible.h:149
void(* ReScanCustomScan)(CustomScanState *node)
Definition: extensible.h:134
Node *(* CreateCustomScanState)(CustomScan *cscan)
Definition: extensible.h:117
const struct TupleTableSlotOps * slotOps
Definition: execnodes.h:1973
const struct CustomExecMethods * methods
Definition: execnodes.h:1972
ScanState ss
Definition: execnodes.h:1967
uint32 flags
Definition: plannodes.h:743
List * custom_scan_tlist
Definition: plannodes.h:748
Scan scan
Definition: plannodes.h:742
const struct CustomScanMethods * methods
Definition: plannodes.h:756
shm_toc_estimator estimator
Definition: parallel.h:42
shm_toc * toc
Definition: parallel.h:45
ExprState * qual
Definition: execnodes.h:1056
Plan * plan
Definition: execnodes.h:1035
EState * state
Definition: execnodes.h:1037
TupleTableSlot * ps_ResultTupleSlot
Definition: execnodes.h:1073
ExecProcNodeMtd ExecProcNode
Definition: execnodes.h:1041
int plan_node_id
Definition: plannodes.h:155
Relation ss_currentRelation
Definition: execnodes.h:1462
TupleTableSlot * ss_ScanTupleSlot
Definition: execnodes.h:1464
PlanState ps
Definition: execnodes.h:1461
Index scanrelid
Definition: plannodes.h:390
static TupleTableSlot * ExecClearTuple(TupleTableSlot *slot)
Definition: tuptable.h:471