test_resowner_basic.c

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/*--------------------------------------------------------------------------
 *
 * test_resowner_basic.c
 *      Test basic ResourceOwner functionality
 *
 * Copyright (c) 2022-2026, PostgreSQL Global Development Group
 *
 * IDENTIFICATION
 *      src/test/modules/test_resowner/test_resowner_basic.c
 *
 * -------------------------------------------------------------------------
 */
#include "postgres.h"
 
#include "fmgr.h"
#include "utils/resowner.h"
 
PG_MODULE_MAGIC;
 
static void ReleaseString(Datum res);
static char *PrintString(Datum res);
 
/*
 * A resource that tracks strings and prints the string when it's released.
 * This makes the order that the resources are released visible.
 */
static const ResourceOwnerDesc string_desc = {
    .name = "test resource",
    .release_phase = RESOURCE_RELEASE_AFTER_LOCKS,
    .release_priority = RELEASE_PRIO_FIRST,
    .ReleaseResource = ReleaseString,
    .DebugPrint = PrintString
};
 
static void
ReleaseString(Datum res)
{
    elog(NOTICE, "releasing string: %s", DatumGetCString(res));
}
 
static char *
PrintString(Datum res)
{
    return psprintf("test string \"%s\"", DatumGetCString(res));
}
 
/* demonstrates phases and priorities between a parent and child context */
PG_FUNCTION_INFO_V1(test_resowner_priorities);
Datum
test_resowner_priorities(PG_FUNCTION_ARGS)
{
    int32       nkinds = PG_GETARG_INT32(0);
    int32       nresources = PG_GETARG_INT32(1);
    ResourceOwner parent,
                child;
    ResourceOwnerDesc *before_desc;
    ResourceOwnerDesc *after_desc;
 
    if (nkinds <= 0)
        elog(ERROR, "nkinds must be greater than zero");
    if (nresources <= 0)
        elog(ERROR, "nresources must be greater than zero");
 
    parent = ResourceOwnerCreate(CurrentResourceOwner, "test parent");
    child = ResourceOwnerCreate(parent, "test child");
 
    before_desc = palloc(nkinds * sizeof(ResourceOwnerDesc));
    for (int i = 0; i < nkinds; i++)
    {
        before_desc[i].name = psprintf("test resource before locks %d", i);
        before_desc[i].release_phase = RESOURCE_RELEASE_BEFORE_LOCKS;
        before_desc[i].release_priority = RELEASE_PRIO_FIRST + i;
        before_desc[i].ReleaseResource = ReleaseString;
        before_desc[i].DebugPrint = PrintString;
    }
    after_desc = palloc(nkinds * sizeof(ResourceOwnerDesc));
    for (int i = 0; i < nkinds; i++)
    {
        after_desc[i].name = psprintf("test resource after locks %d", i);
        after_desc[i].release_phase = RESOURCE_RELEASE_AFTER_LOCKS;
        after_desc[i].release_priority = RELEASE_PRIO_FIRST + i;
        after_desc[i].ReleaseResource = ReleaseString;
        after_desc[i].DebugPrint = PrintString;
    }
 
    /* Add a bunch of resources to child, with different priorities */
    for (int i = 0; i < nresources; i++)
    {
        ResourceOwnerDesc *kind = &before_desc[i % nkinds];
 
        ResourceOwnerEnlarge(child);
        ResourceOwnerRemember(child,
                              CStringGetDatum(psprintf("child before locks priority %d", kind->release_priority)),
                              kind);
    }
    for (int i = 0; i < nresources; i++)
    {
        ResourceOwnerDesc *kind = &after_desc[i % nkinds];
 
        ResourceOwnerEnlarge(child);
        ResourceOwnerRemember(child,
                              CStringGetDatum(psprintf("child after locks priority %d", kind->release_priority)),
                              kind);
    }
 
    /* And also to the parent */
    for (int i = 0; i < nresources; i++)
    {
        ResourceOwnerDesc *kind = &after_desc[i % nkinds];
 
        ResourceOwnerEnlarge(parent);
        ResourceOwnerRemember(parent,
                              CStringGetDatum(psprintf("parent after locks priority %d", kind->release_priority)),
                              kind);
    }
    for (int i = 0; i < nresources; i++)
    {
        ResourceOwnerDesc *kind = &before_desc[i % nkinds];
 
        ResourceOwnerEnlarge(parent);
        ResourceOwnerRemember(parent,
                              CStringGetDatum(psprintf("parent before locks priority %d", kind->release_priority)),
                              kind);
    }
 
    elog(NOTICE, "releasing resources before locks");
    ResourceOwnerRelease(parent, RESOURCE_RELEASE_BEFORE_LOCKS, false, false);
    elog(NOTICE, "releasing locks");
    ResourceOwnerRelease(parent, RESOURCE_RELEASE_LOCKS, false, false);
    elog(NOTICE, "releasing resources after locks");
    ResourceOwnerRelease(parent, RESOURCE_RELEASE_AFTER_LOCKS, false, false);
 
    ResourceOwnerDelete(parent);
 
    PG_RETURN_VOID();
}
 
PG_FUNCTION_INFO_V1(test_resowner_leak);
Datum
test_resowner_leak(PG_FUNCTION_ARGS)
{
    ResourceOwner resowner;
 
    resowner = ResourceOwnerCreate(CurrentResourceOwner, "TestOwner");
 
    ResourceOwnerEnlarge(resowner);
 
    ResourceOwnerRemember(resowner, CStringGetDatum("my string"), &string_desc);
 
    /* don't call ResourceOwnerForget, so that it is leaked */
 
    ResourceOwnerRelease(resowner, RESOURCE_RELEASE_BEFORE_LOCKS, true, false);
    ResourceOwnerRelease(resowner, RESOURCE_RELEASE_LOCKS, true, false);
    ResourceOwnerRelease(resowner, RESOURCE_RELEASE_AFTER_LOCKS, true, false);
 
    ResourceOwnerDelete(resowner);
 
    PG_RETURN_VOID();
}
 
PG_FUNCTION_INFO_V1(test_resowner_remember_between_phases);
Datum
test_resowner_remember_between_phases(PG_FUNCTION_ARGS)
{
    ResourceOwner resowner;
 
    resowner = ResourceOwnerCreate(CurrentResourceOwner, "TestOwner");
 
    ResourceOwnerRelease(resowner, RESOURCE_RELEASE_BEFORE_LOCKS, true, false);
 
    /*
     * Try to remember a new resource.  Fails because we already called
     * ResourceOwnerRelease.
     */
    ResourceOwnerEnlarge(resowner);
    ResourceOwnerRemember(resowner, CStringGetDatum("my string"), &string_desc);
 
    /* unreachable */
    elog(ERROR, "ResourceOwnerEnlarge should have errored out");
 
    PG_RETURN_VOID();
}
 
PG_FUNCTION_INFO_V1(test_resowner_forget_between_phases);
Datum
test_resowner_forget_between_phases(PG_FUNCTION_ARGS)
{
    ResourceOwner resowner;
    Datum       str_resource;
 
    resowner = ResourceOwnerCreate(CurrentResourceOwner, "TestOwner");
 
    ResourceOwnerEnlarge(resowner);
    str_resource = CStringGetDatum("my string");
    ResourceOwnerRemember(resowner, str_resource, &string_desc);
 
    ResourceOwnerRelease(resowner, RESOURCE_RELEASE_BEFORE_LOCKS, true, false);
 
    /*
     * Try to forget the resource that was remembered earlier.  Fails because
     * we already called ResourceOwnerRelease.
     */
    ResourceOwnerForget(resowner, str_resource, &string_desc);
 
    /* unreachable */
    elog(ERROR, "ResourceOwnerForget should have errored out");
 
    PG_RETURN_VOID();
}