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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) 1996-2018, 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/plannodes.h"
18 #include "miscadmin.h"
19 #include "parser/parsetree.h"
20 #include "utils/hsearch.h"
21 #include "utils/memutils.h"
22 #include "utils/rel.h"
23 
24 
25 static TupleTableSlot *ExecCustomScan(PlanState *pstate);
26 
27 
29 ExecInitCustomScan(CustomScan *cscan, EState *estate, int eflags)
30 {
31  CustomScanState *css;
32  Relation scan_rel = NULL;
33  Index scanrelid = cscan->scan.scanrelid;
34  Index tlistvarno;
35 
36  /*
37  * Allocate the CustomScanState object. We let the custom scan provider
38  * do the palloc, in case it wants to make a larger object that embeds
39  * CustomScanState as the first field. It must set the node tag and the
40  * methods field correctly at this time. Other standard fields should be
41  * set to zero.
42  */
44  cscan->methods->CreateCustomScanState(cscan));
45 
46  /* ensure flags is filled correctly */
47  css->flags = cscan->flags;
48 
49  /* fill up fields of ScanState */
50  css->ss.ps.plan = &cscan->scan.plan;
51  css->ss.ps.state = estate;
53 
54  /* create expression context for node */
55  ExecAssignExprContext(estate, &css->ss.ps);
56 
57  /*
58  * open the base relation, if any, and acquire an appropriate lock on it
59  */
60  if (scanrelid > 0)
61  {
62  scan_rel = ExecOpenScanRelation(estate, scanrelid, eflags);
63  css->ss.ss_currentRelation = scan_rel;
64  }
65 
66  /*
67  * Determine the scan tuple type. If the custom scan provider provided a
68  * targetlist describing the scan tuples, use that; else use base
69  * relation's rowtype.
70  */
71  if (cscan->custom_scan_tlist != NIL || scan_rel == NULL)
72  {
73  TupleDesc scan_tupdesc;
74 
75  scan_tupdesc = ExecTypeFromTL(cscan->custom_scan_tlist, false);
76  ExecInitScanTupleSlot(estate, &css->ss, scan_tupdesc);
77  /* Node's targetlist will contain Vars with varno = INDEX_VAR */
78  tlistvarno = INDEX_VAR;
79  }
80  else
81  {
82  ExecInitScanTupleSlot(estate, &css->ss, RelationGetDescr(scan_rel));
83  /* Node's targetlist will contain Vars with varno = scanrelid */
84  tlistvarno = scanrelid;
85  }
86 
87  /*
88  * Initialize result slot, type and projection.
89  */
90  ExecInitResultTupleSlotTL(estate, &css->ss.ps);
91  ExecAssignScanProjectionInfoWithVarno(&css->ss, tlistvarno);
92 
93  /* initialize child expressions */
94  css->ss.ps.qual =
95  ExecInitQual(cscan->scan.plan.qual, (PlanState *) css);
96 
97  /*
98  * The callback of custom-scan provider applies the final initialization
99  * of the custom-scan-state node according to its logic.
100  */
101  css->methods->BeginCustomScan(css, estate, eflags);
102 
103  return css;
104 }
105 
106 static TupleTableSlot *
108 {
109  CustomScanState *node = castNode(CustomScanState, pstate);
110 
112 
113  Assert(node->methods->ExecCustomScan != NULL);
114  return node->methods->ExecCustomScan(node);
115 }
116 
117 void
119 {
120  Assert(node->methods->EndCustomScan != NULL);
121  node->methods->EndCustomScan(node);
122 
123  /* Free the exprcontext */
124  ExecFreeExprContext(&node->ss.ps);
125 
126  /* Clean out the tuple table */
129 
130  /* Close the heap relation */
131  if (node->ss.ss_currentRelation)
133 }
134 
135 void
137 {
138  Assert(node->methods->ReScanCustomScan != NULL);
139  node->methods->ReScanCustomScan(node);
140 }
141 
142 void
144 {
145  if (!node->methods->MarkPosCustomScan)
146  ereport(ERROR,
147  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
148  errmsg("custom scan \"%s\" does not support MarkPos",
149  node->methods->CustomName)));
150  node->methods->MarkPosCustomScan(node);
151 }
152 
153 void
155 {
156  if (!node->methods->RestrPosCustomScan)
157  ereport(ERROR,
158  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
159  errmsg("custom scan \"%s\" does not support MarkPos",
160  node->methods->CustomName)));
161  node->methods->RestrPosCustomScan(node);
162 }
163 
164 void
166 {
167  const CustomExecMethods *methods = node->methods;
168 
169  if (methods->EstimateDSMCustomScan)
170  {
171  node->pscan_len = methods->EstimateDSMCustomScan(node, pcxt);
173  shm_toc_estimate_keys(&pcxt->estimator, 1);
174  }
175 }
176 
177 void
179 {
180  const CustomExecMethods *methods = node->methods;
181 
182  if (methods->InitializeDSMCustomScan)
183  {
184  int plan_node_id = node->ss.ps.plan->plan_node_id;
185  void *coordinate;
186 
187  coordinate = shm_toc_allocate(pcxt->toc, node->pscan_len);
188  methods->InitializeDSMCustomScan(node, pcxt, coordinate);
189  shm_toc_insert(pcxt->toc, plan_node_id, coordinate);
190  }
191 }
192 
193 void
195 {
196  const CustomExecMethods *methods = node->methods;
197 
198  if (methods->ReInitializeDSMCustomScan)
199  {
200  int plan_node_id = node->ss.ps.plan->plan_node_id;
201  void *coordinate;
202 
203  coordinate = shm_toc_lookup(pcxt->toc, plan_node_id, false);
204  methods->ReInitializeDSMCustomScan(node, pcxt, coordinate);
205  }
206 }
207 
208 void
210  ParallelWorkerContext *pwcxt)
211 {
212  const CustomExecMethods *methods = node->methods;
213 
214  if (methods->InitializeWorkerCustomScan)
215  {
216  int plan_node_id = node->ss.ps.plan->plan_node_id;
217  void *coordinate;
218 
219  coordinate = shm_toc_lookup(pwcxt->toc, plan_node_id, false);
220  methods->InitializeWorkerCustomScan(node, pwcxt->toc, coordinate);
221  }
222 }
223 
224 void
226 {
227  const CustomExecMethods *methods = node->methods;
228 
229  if (methods->ShutdownCustomScan)
230  methods->ShutdownCustomScan(node);
231 }
void(* EndCustomScan)(CustomScanState *node)
Definition: extensible.h:129
#define NIL
Definition: pg_list.h:69
List * qual
Definition: plannodes.h:145
Plan plan
Definition: plannodes.h:330
void(* ShutdownCustomScan)(CustomScanState *node)
Definition: extensible.h:148
Index scanrelid
Definition: plannodes.h:331
void ExecCustomScanInitializeWorker(CustomScanState *node, ParallelWorkerContext *pwcxt)
Definition: nodeCustom.c:209
static TupleTableSlot * ExecCustomScan(PlanState *pstate)
Definition: nodeCustom.c:107
#define RelationGetDescr(relation)
Definition: rel.h:437
void ExecCustomScanReInitializeDSM(CustomScanState *node, ParallelContext *pcxt)
Definition: nodeCustom.c:194
#define castNode(_type_, nodeptr)
Definition: nodes.h:582
void ExecShutdownCustomScan(CustomScanState *node)
Definition: nodeCustom.c:225
shm_toc_estimator estimator
Definition: parallel.h:41
TupleTableSlot * ExecClearTuple(TupleTableSlot *slot)
Definition: execTuples.c:475
int plan_node_id
Definition: plannodes.h:143
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:575
TupleTableSlot * ss_ScanTupleSlot
Definition: execnodes.h:1127
Relation ss_currentRelation
Definition: execnodes.h:1125
EState * state
Definition: execnodes.h:870
#define shm_toc_estimate_chunk(e, sz)
Definition: shm_toc.h:51
void ExecFreeExprContext(PlanState *planstate)
Definition: execUtils.c:561
void(* ReScanCustomScan)(CustomScanState *node)
Definition: extensible.h:130
ExprState * ExecInitQual(List *qual, PlanState *parent)
Definition: execExpr.c:204
const struct CustomExecMethods * methods
Definition: execnodes.h:1605
TupleTableSlot *(* ExecCustomScan)(CustomScanState *node)
Definition: extensible.h:128
void ExecAssignScanProjectionInfoWithVarno(ScanState *node, Index varno)
Definition: execScan.c:248
PlanState ps
Definition: execnodes.h:1124
void ExecCustomRestrPos(CustomScanState *node)
Definition: nodeCustom.c:154
TupleTableSlot * ps_ResultTupleSlot
Definition: execnodes.h:901
#define ERROR
Definition: elog.h:43
Relation ExecOpenScanRelation(EState *estate, Index scanrelid, int eflags)
Definition: execUtils.c:638
CustomScanState * ExecInitCustomScan(CustomScan *cscan, EState *estate, int eflags)
Definition: nodeCustom.c:29
ScanState ss
Definition: execnodes.h:1600
Node *(* CreateCustomScanState)(CustomScan *cscan)
Definition: extensible.h:113
const struct CustomScanMethods * methods
Definition: plannodes.h:635
#define ereport(elevel, rest)
Definition: elog.h:122
void(* RestrPosCustomScan)(CustomScanState *node)
Definition: extensible.h:134
TupleDesc ExecTypeFromTL(List *targetList, bool hasoid)
Definition: execTuples.c:944
Scan scan
Definition: plannodes.h:627
ExecProcNodeMtd ExecProcNode
Definition: execnodes.h:874
void(* InitializeWorkerCustomScan)(CustomScanState *node, shm_toc *toc, void *coordinate)
Definition: extensible.h:145
void ExecEndCustomScan(CustomScanState *node)
Definition: nodeCustom.c:118
void ExecCustomMarkPos(CustomScanState *node)
Definition: nodeCustom.c:143
unsigned int Index
Definition: c.h:431
void ExecInitResultTupleSlotTL(EState *estate, PlanState *planstate)
Definition: execTuples.c:870
Plan * plan
Definition: execnodes.h:868
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:178
#define Assert(condition)
Definition: c.h:688
List * custom_scan_tlist
Definition: plannodes.h:633
void ExecAssignExprContext(EState *estate, PlanState *planstate)
Definition: execUtils.c:425
#define shm_toc_estimate_keys(e, cnt)
Definition: shm_toc.h:53
void ExecCloseScanRelation(Relation scanrel)
Definition: execUtils.c:696
void * shm_toc_allocate(shm_toc *toc, Size nbytes)
Definition: shm_toc.c:88
ExprState * qual
Definition: execnodes.h:886
void shm_toc_insert(shm_toc *toc, uint64 key, void *address)
Definition: shm_toc.c:171
int errmsg(const char *fmt,...)
Definition: elog.c:797
void ExecCustomScanEstimate(CustomScanState *node, ParallelContext *pcxt)
Definition: nodeCustom.c:165
void ExecInitScanTupleSlot(EState *estate, ScanState *scanstate, TupleDesc tupledesc)
Definition: execTuples.c:895
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:98
#define INDEX_VAR
Definition: primnodes.h:155
void ExecReScanCustomScan(CustomScanState *node)
Definition: nodeCustom.c:136
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:628