PostgreSQL Source Code: src/backend/executor/nodeCustom.c Source File

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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) 1996-2025, 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 "utils/rel.h"
21
22static TupleTableSlot *ExecCustomScan(PlanState *pstate);
23
24
25CustomScanState *
26 ExecInitCustomScan(CustomScan *cscan, EState *estate, int eflags)
27{
28 CustomScanState *css;
29 const TupleTableSlotOps *slotOps;
30 Relation scan_rel = NULL;
31 Index scanrelid = cscan->scan.scanrelid;
32 int tlistvarno;
33
34 /*
35 * Allocate the CustomScanState object. We let the custom scan provider
36 * do the palloc, in case it wants to make a larger object that embeds
37 * CustomScanState as the first field. It must set the node tag and the
38 * methods field correctly at this time. Other standard fields should be
39 * set to zero.
40 */
41 css = castNode(CustomScanState,
42 cscan->methods->CreateCustomScanState(cscan));
43
44 /* ensure flags is filled correctly */
45 css->flags = cscan->flags;
46
47 /* fill up fields of ScanState */
48 css->ss.ps.plan = &cscan->scan.plan;
49 css->ss.ps.state = estate;
50 css->ss.ps.ExecProcNode = ExecCustomScan;
51
52 /* create expression context for node */
53 ExecAssignExprContext(estate, &css->ss.ps);
54
55 /*
56 * open the scan relation, if any
57 */
58 if (scanrelid > 0)
59 {
60 scan_rel = ExecOpenScanRelation(estate, scanrelid, eflags);
61 css->ss.ss_currentRelation = scan_rel;
62 }
63
64 /*
65 * Use a custom slot if specified in CustomScanState or use virtual slot
66 * otherwise.
67 */
68 slotOps = css->slotOps;
69 if (!slotOps)
70 slotOps = &TTSOpsVirtual;
71
72 /*
73 * Determine the scan tuple type. If the custom scan provider provided a
74 * targetlist describing the scan tuples, use that; else use base
75 * relation's rowtype.
76 */
77 if (cscan->custom_scan_tlist != NIL || scan_rel == NULL)
78 {
79 TupleDesc scan_tupdesc;
80
81 scan_tupdesc = ExecTypeFromTL(cscan->custom_scan_tlist);
82 ExecInitScanTupleSlot(estate, &css->ss, scan_tupdesc, slotOps);
83 /* Node's targetlist will contain Vars with varno = INDEX_VAR */
84 tlistvarno = INDEX_VAR;
85 }
86 else
87 {
88 ExecInitScanTupleSlot(estate, &css->ss, RelationGetDescr(scan_rel),
89 slotOps);
90 /* Node's targetlist will contain Vars with varno = scanrelid */
91 tlistvarno = scanrelid;
92 }
93
94 /*
95 * Initialize result slot, type and projection.
96 */
97 ExecInitResultTupleSlotTL(&css->ss.ps, &TTSOpsVirtual);
98 ExecAssignScanProjectionInfoWithVarno(&css->ss, tlistvarno);
99
100 /* initialize child expressions */
101 css->ss.ps.qual =
102 ExecInitQual(cscan->scan.plan.qual, (PlanState *) css);
103
104 /*
105 * The callback of custom-scan provider applies the final initialization
106 * of the custom-scan-state node according to its logic.
107 */
108 css->methods->BeginCustomScan(css, estate, eflags);
109
110 return css;
111}
112
113static TupleTableSlot *
114 ExecCustomScan(PlanState *pstate)
115{
116 CustomScanState *node = castNode(CustomScanState, pstate);
117
118 CHECK_FOR_INTERRUPTS();
119
120 Assert(node->methods->ExecCustomScan != NULL);
121 return node->methods->ExecCustomScan(node);
122}
123
124void
125 ExecEndCustomScan(CustomScanState *node)
126{
127 Assert(node->methods->EndCustomScan != NULL);
128 node->methods->EndCustomScan(node);
129}
130
131void
132 ExecReScanCustomScan(CustomScanState *node)
133{
134 Assert(node->methods->ReScanCustomScan != NULL);
135 node->methods->ReScanCustomScan(node);
136}
137
138void
139 ExecCustomMarkPos(CustomScanState *node)
140{
141 if (!node->methods->MarkPosCustomScan)
142 ereport(ERROR,
143 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
144 errmsg("custom scan \"%s\" does not support MarkPos",
145 node->methods->CustomName)));
146 node->methods->MarkPosCustomScan(node);
147}
148
149void
150 ExecCustomRestrPos(CustomScanState *node)
151{
152 if (!node->methods->RestrPosCustomScan)
153 ereport(ERROR,
154 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
155 errmsg("custom scan \"%s\" does not support MarkPos",
156 node->methods->CustomName)));
157 node->methods->RestrPosCustomScan(node);
158}
159
160void
161 ExecCustomScanEstimate(CustomScanState *node, ParallelContext *pcxt)
162{
163 const CustomExecMethods *methods = node->methods;
164
165 if (methods->EstimateDSMCustomScan)
166 {
167 node->pscan_len = methods->EstimateDSMCustomScan(node, pcxt);
168 shm_toc_estimate_chunk(&pcxt->estimator, node->pscan_len);
169 shm_toc_estimate_keys(&pcxt->estimator, 1);
170 }
171}
172
173void
174 ExecCustomScanInitializeDSM(CustomScanState *node, ParallelContext *pcxt)
175{
176 const CustomExecMethods *methods = node->methods;
177
178 if (methods->InitializeDSMCustomScan)
179 {
180 int plan_node_id = node->ss.ps.plan->plan_node_id;
181 void *coordinate;
182
183 coordinate = shm_toc_allocate(pcxt->toc, node->pscan_len);
184 methods->InitializeDSMCustomScan(node, pcxt, coordinate);
185 shm_toc_insert(pcxt->toc, plan_node_id, coordinate);
186 }
187}
188
189void
190 ExecCustomScanReInitializeDSM(CustomScanState *node, ParallelContext *pcxt)
191{
192 const CustomExecMethods *methods = node->methods;
193
194 if (methods->ReInitializeDSMCustomScan)
195 {
196 int plan_node_id = node->ss.ps.plan->plan_node_id;
197 void *coordinate;
198
199 coordinate = shm_toc_lookup(pcxt->toc, plan_node_id, false);
200 methods->ReInitializeDSMCustomScan(node, pcxt, coordinate);
201 }
202}
203
204void
205 ExecCustomScanInitializeWorker(CustomScanState *node,
206 ParallelWorkerContext *pwcxt)
207{
208 const CustomExecMethods *methods = node->methods;
209
210 if (methods->InitializeWorkerCustomScan)
211 {
212 int plan_node_id = node->ss.ps.plan->plan_node_id;
213 void *coordinate;
214
215 coordinate = shm_toc_lookup(pwcxt->toc, plan_node_id, false);
216 methods->InitializeWorkerCustomScan(node, pwcxt->toc, coordinate);
217 }
218}
219
220void
221 ExecShutdownCustomScan(CustomScanState *node)
222{
223 const CustomExecMethods *methods = node->methods;
224
225 if (methods->ShutdownCustomScan)
226 methods->ShutdownCustomScan(node);
227}
unsigned int Index
Definition: c.h:619
int errcode(int sqlerrcode)
Definition: elog.c:854
int errmsg(const char *fmt,...)
Definition: elog.c:1071
#define ERROR
Definition: elog.h:39
#define ereport(elevel,...)
Definition: elog.h:150
ExprState * ExecInitQual(List *qual, PlanState *parent)
Definition: execExpr.c:229
void ExecAssignScanProjectionInfoWithVarno(ScanState *node, int varno)
Definition: execScan.c:94
const TupleTableSlotOps TTSOpsVirtual
Definition: execTuples.c:84
void ExecInitScanTupleSlot(EState *estate, ScanState *scanstate, TupleDesc tupledesc, const TupleTableSlotOps *tts_ops)
Definition: execTuples.c:2000
void ExecInitResultTupleSlotTL(PlanState *planstate, const TupleTableSlotOps *tts_ops)
Definition: execTuples.c:1988
TupleDesc ExecTypeFromTL(List *targetList)
Definition: execTuples.c:2127
void ExecAssignExprContext(EState *estate, PlanState *planstate)
Definition: execUtils.c:485
Relation ExecOpenScanRelation(EState *estate, Index scanrelid, int eflags)
Definition: execUtils.c:742
Assert(PointerIsAligned(start, uint64))
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:122
void ExecCustomScanInitializeDSM(CustomScanState *node, ParallelContext *pcxt)
Definition: nodeCustom.c:174
void ExecShutdownCustomScan(CustomScanState *node)
Definition: nodeCustom.c:221
void ExecCustomScanEstimate(CustomScanState *node, ParallelContext *pcxt)
Definition: nodeCustom.c:161
void ExecCustomRestrPos(CustomScanState *node)
Definition: nodeCustom.c:150
void ExecReScanCustomScan(CustomScanState *node)
Definition: nodeCustom.c:132
void ExecCustomScanReInitializeDSM(CustomScanState *node, ParallelContext *pcxt)
Definition: nodeCustom.c:190
void ExecEndCustomScan(CustomScanState *node)
Definition: nodeCustom.c:125
void ExecCustomScanInitializeWorker(CustomScanState *node, ParallelWorkerContext *pwcxt)
Definition: nodeCustom.c:205
void ExecCustomMarkPos(CustomScanState *node)
Definition: nodeCustom.c:139
CustomScanState * ExecInitCustomScan(CustomScan *cscan, EState *estate, int eflags)
Definition: nodeCustom.c:26
static TupleTableSlot * ExecCustomScan(PlanState *pstate)
Definition: nodeCustom.c:114
#define castNode(_type_, nodeptr)
Definition: nodes.h:182
#define NIL
Definition: pg_list.h:68
#define INDEX_VAR
Definition: primnodes.h:244
#define RelationGetDescr(relation)
Definition: rel.h:540
void * shm_toc_allocate(shm_toc *toc, Size nbytes)
Definition: shm_toc.c:88
void shm_toc_insert(shm_toc *toc, uint64 key, void *address)
Definition: shm_toc.c:171
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
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
TupleTableSlot *(* ExecCustomScan)(CustomScanState *node)
Definition: extensible.h:132
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:2137
const struct CustomExecMethods * methods
Definition: execnodes.h:2136
Size pscan_len
Definition: execnodes.h:2135
uint32 flags
Definition: execnodes.h:2132
ScanState ss
Definition: execnodes.h:2131
uint32 flags
Definition: plannodes.h:908
List * custom_scan_tlist
Definition: plannodes.h:916
Scan scan
Definition: plannodes.h:906
const struct CustomScanMethods * methods
Definition: plannodes.h:925
Definition: execnodes.h:655
shm_toc_estimator estimator
Definition: parallel.h:41
shm_toc * toc
Definition: parallel.h:44
shm_toc * toc
Definition: parallel.h:53
ExprState * qual
Definition: execnodes.h:1180
Plan * plan
Definition: execnodes.h:1159
EState * state
Definition: execnodes.h:1161
ExecProcNodeMtd ExecProcNode
Definition: execnodes.h:1165
int plan_node_id
Definition: plannodes.h:218
Definition: rel.h:56
Relation ss_currentRelation
Definition: execnodes.h:1616
PlanState ps
Definition: execnodes.h:1615
Index scanrelid
Definition: plannodes.h:516

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