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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) 1996-2019, 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 "nodes/execnodes.h"
17 #include "nodes/extensible.h"
18 #include "nodes/plannodes.h"
19 #include "miscadmin.h"
20 #include "parser/parsetree.h"
21 #include "utils/hsearch.h"
22 #include "utils/memutils.h"
23 #include "utils/rel.h"
24 
25 
26 static TupleTableSlot *ExecCustomScan(PlanState *pstate);
27 
28 
30 ExecInitCustomScan(CustomScan *cscan, EState *estate, int eflags)
31 {
32  CustomScanState *css;
33  Relation scan_rel = NULL;
34  Index scanrelid = cscan->scan.scanrelid;
35  Index 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  * Determine the scan tuple type. If the custom scan provider provided a
69  * targetlist describing the scan tuples, use that; else use base
70  * relation's rowtype.
71  */
72  if (cscan->custom_scan_tlist != NIL || scan_rel == NULL)
73  {
74  TupleDesc scan_tupdesc;
75 
76  scan_tupdesc = ExecTypeFromTL(cscan->custom_scan_tlist);
77  ExecInitScanTupleSlot(estate, &css->ss, scan_tupdesc, &TTSOpsVirtual);
78  /* Node's targetlist will contain Vars with varno = INDEX_VAR */
79  tlistvarno = INDEX_VAR;
80  }
81  else
82  {
83  ExecInitScanTupleSlot(estate, &css->ss, RelationGetDescr(scan_rel),
84  &TTSOpsVirtual);
85  /* Node's targetlist will contain Vars with varno = scanrelid */
86  tlistvarno = scanrelid;
87  }
88 
89  /*
90  * Initialize result slot, type and projection.
91  */
93  ExecAssignScanProjectionInfoWithVarno(&css->ss, tlistvarno);
94 
95  /* initialize child expressions */
96  css->ss.ps.qual =
97  ExecInitQual(cscan->scan.plan.qual, (PlanState *) css);
98 
99  /*
100  * The callback of custom-scan provider applies the final initialization
101  * of the custom-scan-state node according to its logic.
102  */
103  css->methods->BeginCustomScan(css, estate, eflags);
104 
105  return css;
106 }
107 
108 static TupleTableSlot *
110 {
111  CustomScanState *node = castNode(CustomScanState, pstate);
112 
114 
115  Assert(node->methods->ExecCustomScan != NULL);
116  return node->methods->ExecCustomScan(node);
117 }
118 
119 void
121 {
122  Assert(node->methods->EndCustomScan != NULL);
123  node->methods->EndCustomScan(node);
124 
125  /* Free the exprcontext */
126  ExecFreeExprContext(&node->ss.ps);
127 
128  /* Clean out the tuple table */
131 }
132 
133 void
135 {
136  Assert(node->methods->ReScanCustomScan != NULL);
137  node->methods->ReScanCustomScan(node);
138 }
139 
140 void
142 {
143  if (!node->methods->MarkPosCustomScan)
144  ereport(ERROR,
145  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
146  errmsg("custom scan \"%s\" does not support MarkPos",
147  node->methods->CustomName)));
148  node->methods->MarkPosCustomScan(node);
149 }
150 
151 void
153 {
154  if (!node->methods->RestrPosCustomScan)
155  ereport(ERROR,
156  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
157  errmsg("custom scan \"%s\" does not support MarkPos",
158  node->methods->CustomName)));
159  node->methods->RestrPosCustomScan(node);
160 }
161 
162 void
164 {
165  const CustomExecMethods *methods = node->methods;
166 
167  if (methods->EstimateDSMCustomScan)
168  {
169  node->pscan_len = methods->EstimateDSMCustomScan(node, pcxt);
171  shm_toc_estimate_keys(&pcxt->estimator, 1);
172  }
173 }
174 
175 void
177 {
178  const CustomExecMethods *methods = node->methods;
179 
180  if (methods->InitializeDSMCustomScan)
181  {
182  int plan_node_id = node->ss.ps.plan->plan_node_id;
183  void *coordinate;
184 
185  coordinate = shm_toc_allocate(pcxt->toc, node->pscan_len);
186  methods->InitializeDSMCustomScan(node, pcxt, coordinate);
187  shm_toc_insert(pcxt->toc, plan_node_id, coordinate);
188  }
189 }
190 
191 void
193 {
194  const CustomExecMethods *methods = node->methods;
195 
196  if (methods->ReInitializeDSMCustomScan)
197  {
198  int plan_node_id = node->ss.ps.plan->plan_node_id;
199  void *coordinate;
200 
201  coordinate = shm_toc_lookup(pcxt->toc, plan_node_id, false);
202  methods->ReInitializeDSMCustomScan(node, pcxt, coordinate);
203  }
204 }
205 
206 void
208  ParallelWorkerContext *pwcxt)
209 {
210  const CustomExecMethods *methods = node->methods;
211 
212  if (methods->InitializeWorkerCustomScan)
213  {
214  int plan_node_id = node->ss.ps.plan->plan_node_id;
215  void *coordinate;
216 
217  coordinate = shm_toc_lookup(pwcxt->toc, plan_node_id, false);
218  methods->InitializeWorkerCustomScan(node, pwcxt->toc, coordinate);
219  }
220 }
221 
222 void
224 {
225  const CustomExecMethods *methods = node->methods;
226 
227  if (methods->ShutdownCustomScan)
228  methods->ShutdownCustomScan(node);
229 }
void(* EndCustomScan)(CustomScanState *node)
Definition: extensible.h:129
#define NIL
Definition: pg_list.h:65
List * qual
Definition: plannodes.h:141
Plan plan
Definition: plannodes.h:340
void(* ShutdownCustomScan)(CustomScanState *node)
Definition: extensible.h:148
Index scanrelid
Definition: plannodes.h:341
void ExecCustomScanInitializeWorker(CustomScanState *node, ParallelWorkerContext *pwcxt)
Definition: nodeCustom.c:207
static TupleTableSlot * ExecClearTuple(TupleTableSlot *slot)
Definition: tuptable.h:426
static TupleTableSlot * ExecCustomScan(PlanState *pstate)
Definition: nodeCustom.c:109
#define RelationGetDescr(relation)
Definition: rel.h:445
void ExecCustomScanReInitializeDSM(CustomScanState *node, ParallelContext *pcxt)
Definition: nodeCustom.c:192
#define castNode(_type_, nodeptr)
Definition: nodes.h:594
void ExecShutdownCustomScan(CustomScanState *node)
Definition: nodeCustom.c:223
shm_toc_estimator estimator
Definition: parallel.h:41
const TupleTableSlotOps TTSOpsVirtual
Definition: execTuples.c:84
int plan_node_id
Definition: plannodes.h:139
void(* ReInitializeDSMCustomScan)(CustomScanState *node, ParallelContext *pcxt, void *coordinate)
Definition: extensible.h:142
Size(* EstimateDSMCustomScan)(CustomScanState *node, ParallelContext *pcxt)
Definition: extensible.h:137
int errcode(int sqlerrcode)
Definition: elog.c:570
TupleTableSlot * ss_ScanTupleSlot
Definition: execnodes.h:1334
Relation ss_currentRelation
Definition: execnodes.h:1332
EState * state
Definition: execnodes.h:942
#define shm_toc_estimate_chunk(e, sz)
Definition: shm_toc.h:51
void ExecFreeExprContext(PlanState *planstate)
Definition: execUtils.c:614
void(* ReScanCustomScan)(CustomScanState *node)
Definition: extensible.h:130
ExprState * ExecInitQual(List *qual, PlanState *parent)
Definition: execExpr.c:207
const struct CustomExecMethods * methods
Definition: execnodes.h:1815
TupleTableSlot *(* ExecCustomScan)(CustomScanState *node)
Definition: extensible.h:128
void ExecAssignScanProjectionInfoWithVarno(ScanState *node, Index varno)
Definition: execScan.c:285
PlanState ps
Definition: execnodes.h:1331
void ExecCustomRestrPos(CustomScanState *node)
Definition: nodeCustom.c:152
TupleTableSlot * ps_ResultTupleSlot
Definition: execnodes.h:978
#define ERROR
Definition: elog.h:43
Relation ExecOpenScanRelation(EState *estate, Index scanrelid, int eflags)
Definition: execUtils.c:693
CustomScanState * ExecInitCustomScan(CustomScan *cscan, EState *estate, int eflags)
Definition: nodeCustom.c:30
ScanState ss
Definition: execnodes.h:1810
void ExecInitScanTupleSlot(EState *estate, ScanState *scanstate, TupleDesc tupledesc, const TupleTableSlotOps *tts_ops)
Definition: execTuples.c:1776
Node *(* CreateCustomScanState)(CustomScan *cscan)
Definition: extensible.h:113
const struct CustomScanMethods * methods
Definition: plannodes.h:646
#define ereport(elevel, rest)
Definition: elog.h:141
void(* RestrPosCustomScan)(CustomScanState *node)
Definition: extensible.h:134
Scan scan
Definition: plannodes.h:638
ExecProcNodeMtd ExecProcNode
Definition: execnodes.h:946
void(* InitializeWorkerCustomScan)(CustomScanState *node, shm_toc *toc, void *coordinate)
Definition: extensible.h:145
void ExecEndCustomScan(CustomScanState *node)
Definition: nodeCustom.c:120
void ExecCustomMarkPos(CustomScanState *node)
Definition: nodeCustom.c:141
unsigned int Index
Definition: c.h:475
Plan * plan
Definition: execnodes.h:940
const char * CustomName
Definition: extensible.h:122
void(* InitializeDSMCustomScan)(CustomScanState *node, ParallelContext *pcxt, void *coordinate)
Definition: extensible.h:139
void ExecCustomScanInitializeDSM(CustomScanState *node, ParallelContext *pcxt)
Definition: nodeCustom.c:176
#define Assert(condition)
Definition: c.h:732
List * custom_scan_tlist
Definition: plannodes.h:644
void ExecAssignExprContext(EState *estate, PlanState *planstate)
Definition: execUtils.c:444
#define shm_toc_estimate_keys(e, cnt)
Definition: shm_toc.h:53
TupleDesc ExecTypeFromTL(List *targetList)
Definition: execTuples.c:1904
void ExecInitResultTupleSlotTL(PlanState *planstate, const TupleTableSlotOps *tts_ops)
Definition: execTuples.c:1764
void * shm_toc_allocate(shm_toc *toc, Size nbytes)
Definition: shm_toc.c:88
ExprState * qual
Definition: execnodes.h:961
void shm_toc_insert(shm_toc *toc, uint64 key, void *address)
Definition: shm_toc.c:171
int errmsg(const char *fmt,...)
Definition: elog.c:784
void ExecCustomScanEstimate(CustomScanState *node, ParallelContext *pcxt)
Definition: nodeCustom.c:163
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:99
#define INDEX_VAR
Definition: primnodes.h:159
void ExecReScanCustomScan(CustomScanState *node)
Definition: nodeCustom.c:134
void * shm_toc_lookup(shm_toc *toc, uint64 key, bool noError)
Definition: shm_toc.c:232
shm_toc * toc
Definition: parallel.h:44
void(* MarkPosCustomScan)(CustomScanState *node)
Definition: extensible.h:133
uint32 flags
Definition: plannodes.h:639