test_lwlock_tranches.c

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/*--------------------------------------------------------------------------
 *
 * test_lwlock_tranches.c
 *      Test code for LWLock tranches allocated by extensions.
 *
 * Copyright (c) 2025, PostgreSQL Global Development Group
 *
 * IDENTIFICATION
 *      src/test/modules/test_lwlock_tranches/test_lwlock_tranches.c
 *
 * -------------------------------------------------------------------------
 */
 
#include "postgres.h"
 
#include "fmgr.h"
#include "miscadmin.h"
#include "storage/lwlock.h"
#include "utils/builtins.h"
#include "utils/wait_classes.h"
 
PG_MODULE_MAGIC;
 
#define STARTUP_TRANCHE_NAME "test_lwlock_tranches_startup"
#define DYNAMIC_TRANCHE_NAME "test_lwlock_tranches_dynamic"
 
#define NUM_STARTUP_TRANCHES (32)
#define NUM_DYNAMIC_TRANCHES (256 - NUM_STARTUP_TRANCHES)
 
#define GET_TRANCHE_NAME(a) GetLWLockIdentifier(PG_WAIT_LWLOCK, (a))
 
static shmem_request_hook_type prev_shmem_request_hook;
static void test_lwlock_tranches_shmem_request(void);
 
void
_PG_init(void)
{
    prev_shmem_request_hook = shmem_request_hook;
    shmem_request_hook = test_lwlock_tranches_shmem_request;
}
 
static void
test_lwlock_tranches_shmem_request(void)
{
    if (prev_shmem_request_hook)
        prev_shmem_request_hook();
 
    for (int i = 0; i < NUM_STARTUP_TRANCHES; i++)
        RequestNamedLWLockTranche(STARTUP_TRANCHE_NAME, 1);
}
 
/*
 * Checks that GetLWLockIdentifier() returns the expected value for tranches
 * registered via RequestNamedLWLockTranche() and LWLockNewTrancheId().
 */
PG_FUNCTION_INFO_V1(test_lwlock_tranches);
Datum
test_lwlock_tranches(PG_FUNCTION_ARGS)
{
    int         dynamic_tranches[NUM_DYNAMIC_TRANCHES];
 
    for (int i = 0; i < NUM_DYNAMIC_TRANCHES; i++)
        dynamic_tranches[i] = LWLockNewTrancheId(DYNAMIC_TRANCHE_NAME);
 
    for (int i = 0; i < NUM_STARTUP_TRANCHES; i++)
    {
        if (strcmp(GET_TRANCHE_NAME(LWTRANCHE_FIRST_USER_DEFINED + i),
                   STARTUP_TRANCHE_NAME) != 0)
            elog(ERROR, "incorrect startup lock tranche name");
    }
 
    for (int i = 0; i < NUM_DYNAMIC_TRANCHES; i++)
    {
        if (strcmp(GET_TRANCHE_NAME(dynamic_tranches[i]),
                   DYNAMIC_TRANCHE_NAME) != 0)
            elog(ERROR, "incorrect dynamic lock tranche name");
    }
 
    PG_RETURN_VOID();
}
 
/*
 * Wrapper for LWLockNewTrancheId().
 */
PG_FUNCTION_INFO_V1(test_lwlock_tranche_creation);
Datum
test_lwlock_tranche_creation(PG_FUNCTION_ARGS)
{
    char       *tranche_name = PG_ARGISNULL(0) ? NULL : TextDatumGetCString(PG_GETARG_DATUM(0));
 
    (void) LWLockNewTrancheId(tranche_name);
 
    PG_RETURN_VOID();
}
 
/*
 * Wrapper for GetNamedLWLockTranche().
 */
PG_FUNCTION_INFO_V1(test_lwlock_tranche_lookup);
Datum
test_lwlock_tranche_lookup(PG_FUNCTION_ARGS)
{
    char       *tranche_name = TextDatumGetCString(PG_GETARG_DATUM(0));
 
    (void) GetNamedLWLockTranche(tranche_name);
 
    PG_RETURN_VOID();
}
 
/*
 * Wrapper for LWLockInitialize().
 */
PG_FUNCTION_INFO_V1(test_lwlock_initialize);
Datum
test_lwlock_initialize(PG_FUNCTION_ARGS)
{
    int         tranche_id = PG_GETARG_INT32(0);
    LWLock      lock;
 
    LWLockInitialize(&lock, tranche_id);
 
    PG_RETURN_VOID();
}