1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
|
/* ------------------------------------------------------------------------
*
* nodeCustom.c
* Routines to handle execution of custom scan node
*
* Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* ------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/parallel.h"
#include "executor/executor.h"
#include "executor/nodeCustom.h"
#include "nodes/execnodes.h"
#include "nodes/plannodes.h"
#include "parser/parsetree.h"
#include "utils/hsearch.h"
#include "utils/memutils.h"
#include "utils/rel.h"
CustomScanState *
ExecInitCustomScan(CustomScan *cscan, EState *estate, int eflags)
{
CustomScanState *css;
Relation scan_rel = NULL;
Index scanrelid = cscan->scan.scanrelid;
Index tlistvarno;
/*
* Allocate the CustomScanState object. We let the custom scan provider
* do the palloc, in case it wants to make a larger object that embeds
* CustomScanState as the first field. It must set the node tag and the
* methods field correctly at this time. Other standard fields should be
* set to zero.
*/
css = castNode(CustomScanState,
cscan->methods->CreateCustomScanState(cscan));
/* ensure flags is filled correctly */
css->flags = cscan->flags;
/* fill up fields of ScanState */
css->ss.ps.plan = &cscan->scan.plan;
css->ss.ps.state = estate;
/* create expression context for node */
ExecAssignExprContext(estate, &css->ss.ps);
/* initialize child expressions */
css->ss.ps.qual =
ExecInitQual(cscan->scan.plan.qual, (PlanState *) css);
/* tuple table initialization */
ExecInitScanTupleSlot(estate, &css->ss);
ExecInitResultTupleSlot(estate, &css->ss.ps);
/*
* open the base relation, if any, and acquire an appropriate lock on it
*/
if (scanrelid > 0)
{
scan_rel = ExecOpenScanRelation(estate, scanrelid, eflags);
css->ss.ss_currentRelation = scan_rel;
}
/*
* Determine the scan tuple type. If the custom scan provider provided a
* targetlist describing the scan tuples, use that; else use base
* relation's rowtype.
*/
if (cscan->custom_scan_tlist != NIL || scan_rel == NULL)
{
TupleDesc scan_tupdesc;
scan_tupdesc = ExecTypeFromTL(cscan->custom_scan_tlist, false);
ExecAssignScanType(&css->ss, scan_tupdesc);
/* Node's targetlist will contain Vars with varno = INDEX_VAR */
tlistvarno = INDEX_VAR;
}
else
{
ExecAssignScanType(&css->ss, RelationGetDescr(scan_rel));
/* Node's targetlist will contain Vars with varno = scanrelid */
tlistvarno = scanrelid;
}
/*
* Initialize result tuple type and projection info.
*/
ExecAssignResultTypeFromTL(&css->ss.ps);
ExecAssignScanProjectionInfoWithVarno(&css->ss, tlistvarno);
/*
* The callback of custom-scan provider applies the final initialization
* of the custom-scan-state node according to its logic.
*/
css->methods->BeginCustomScan(css, estate, eflags);
return css;
}
TupleTableSlot *
ExecCustomScan(CustomScanState *node)
{
Assert(node->methods->ExecCustomScan != NULL);
return node->methods->ExecCustomScan(node);
}
void
ExecEndCustomScan(CustomScanState *node)
{
Assert(node->methods->EndCustomScan != NULL);
node->methods->EndCustomScan(node);
/* Free the exprcontext */
ExecFreeExprContext(&node->ss.ps);
/* Clean out the tuple table */
ExecClearTuple(node->ss.ps.ps_ResultTupleSlot);
ExecClearTuple(node->ss.ss_ScanTupleSlot);
/* Close the heap relation */
if (node->ss.ss_currentRelation)
ExecCloseScanRelation(node->ss.ss_currentRelation);
}
void
ExecReScanCustomScan(CustomScanState *node)
{
Assert(node->methods->ReScanCustomScan != NULL);
node->methods->ReScanCustomScan(node);
}
void
ExecCustomMarkPos(CustomScanState *node)
{
if (!node->methods->MarkPosCustomScan)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("custom scan \"%s\" does not support MarkPos",
node->methods->CustomName)));
node->methods->MarkPosCustomScan(node);
}
void
ExecCustomRestrPos(CustomScanState *node)
{
if (!node->methods->RestrPosCustomScan)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("custom scan \"%s\" does not support MarkPos",
node->methods->CustomName)));
node->methods->RestrPosCustomScan(node);
}
void
ExecCustomScanEstimate(CustomScanState *node, ParallelContext *pcxt)
{
const CustomExecMethods *methods = node->methods;
if (methods->EstimateDSMCustomScan)
{
node->pscan_len = methods->EstimateDSMCustomScan(node, pcxt);
shm_toc_estimate_chunk(&pcxt->estimator, node->pscan_len);
shm_toc_estimate_keys(&pcxt->estimator, 1);
}
}
void
ExecCustomScanInitializeDSM(CustomScanState *node, ParallelContext *pcxt)
{
const CustomExecMethods *methods = node->methods;
if (methods->InitializeDSMCustomScan)
{
int plan_node_id = node->ss.ps.plan->plan_node_id;
void *coordinate;
coordinate = shm_toc_allocate(pcxt->toc, node->pscan_len);
methods->InitializeDSMCustomScan(node, pcxt, coordinate);
shm_toc_insert(pcxt->toc, plan_node_id, coordinate);
}
}
void
ExecCustomScanInitializeWorker(CustomScanState *node, shm_toc *toc)
{
const CustomExecMethods *methods = node->methods;
if (methods->InitializeWorkerCustomScan)
{
int plan_node_id = node->ss.ps.plan->plan_node_id;
void *coordinate;
coordinate = shm_toc_lookup(toc, plan_node_id);
methods->InitializeWorkerCustomScan(node, toc, coordinate);
}
}
void
ExecShutdownCustomScan(CustomScanState *node)
{
const CustomExecMethods *methods = node->methods;
if (methods->ShutdownCustomScan)
methods->ShutdownCustomScan(node);
}
|
