PostgreSQL Source Code git master
delay_execution.c
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1/*-------------------------------------------------------------------------
2 *
3 * delay_execution.c
4 * Test module to allow delay between parsing and execution of a query.
5 *
6 * The delay is implemented by taking and immediately releasing a specified
7 * advisory lock. If another process has previously taken that lock, the
8 * current process will be blocked until the lock is released; otherwise,
9 * there's no effect. This allows an isolationtester script to reliably
10 * test behaviors where some specified action happens in another backend
11 * between parsing and execution of any desired query.
12 *
13 * Copyright (c) 2020-2025, PostgreSQL Global Development Group
14 *
15 * IDENTIFICATION
16 * src/test/modules/delay_execution/delay_execution.c
17 *
18 *-------------------------------------------------------------------------
19 */
20
21#include "postgres.h"
22
23#include <limits.h>
24
25#include "optimizer/planner.h"
26#include "utils/fmgrprotos.h"
27#include "utils/guc.h"
28#include "utils/inval.h"
29
30
32
33/* GUC: advisory lock ID to use. Zero disables the feature. */
34static int post_planning_lock_id = 0;
35
36/* Save previous planner hook user to be a good citizen */
38
39
40/* planner_hook function to provide the desired delay */
41static PlannedStmt *
42delay_execution_planner(Query *parse, const char *query_string,
43 int cursorOptions, ParamListInfo boundParams)
44{
45 PlannedStmt *result;
46
47 /* Invoke the planner, possibly via a previous hook user */
49 result = prev_planner_hook(parse, query_string, cursorOptions,
50 boundParams);
51 else
52 result = standard_planner(parse, query_string, cursorOptions,
53 boundParams);
54
55 /* If enabled, delay by taking and releasing the specified lock */
56 if (post_planning_lock_id != 0)
57 {
62
63 /*
64 * Ensure that we notice any pending invalidations, since the advisory
65 * lock functions don't do this.
66 */
68 }
69
70 return result;
71}
72
73/* Module load function */
74void
76{
77 /* Set up the GUC to control which lock is used */
78 DefineCustomIntVariable("delay_execution.post_planning_lock_id",
79 "Sets the advisory lock ID to be locked/unlocked after planning.",
80 "Zero disables the delay.",
82 0,
83 0, INT_MAX,
85 0,
86 NULL,
87 NULL,
88 NULL);
89
90 MarkGUCPrefixReserved("delay_execution");
91
92 /* Install our hook */
95}
int64_t int64
Definition: c.h:485
static planner_hook_type prev_planner_hook
void _PG_init(void)
PG_MODULE_MAGIC
static PlannedStmt * delay_execution_planner(Query *parse, const char *query_string, int cursorOptions, ParamListInfo boundParams)
static int post_planning_lock_id
Datum Int64GetDatum(int64 X)
Definition: fmgr.c:1807
#define DirectFunctionCall1(func, arg1)
Definition: fmgr.h:641
void MarkGUCPrefixReserved(const char *className)
Definition: guc.c:5279
void DefineCustomIntVariable(const char *name, const char *short_desc, const char *long_desc, int *valueAddr, int bootValue, int minValue, int maxValue, GucContext context, int flags, GucIntCheckHook check_hook, GucIntAssignHook assign_hook, GucShowHook show_hook)
Definition: guc.c:5158
@ PGC_USERSET
Definition: guc.h:79
void AcceptInvalidationMessages(void)
Definition: inval.c:864
Datum pg_advisory_unlock_int8(PG_FUNCTION_ARGS)
Definition: lockfuncs.c:772
Datum pg_advisory_lock_int8(PG_FUNCTION_ARGS)
Definition: lockfuncs.c:626
planner_hook_type planner_hook
Definition: planner.c:72
PlannedStmt * standard_planner(Query *parse, const char *query_string, int cursorOptions, ParamListInfo boundParams)
Definition: planner.c:297
PlannedStmt *(* planner_hook_type)(Query *parse, const char *query_string, int cursorOptions, ParamListInfo boundParams)
Definition: planner.h:26
static struct subre * parse(struct vars *v, int stopper, int type, struct state *init, struct state *final)
Definition: regcomp.c:717