lockfuncs.c File Reference

#include "postgres.h"
#include "access/htup_details.h"
#include "access/xact.h"
#include "catalog/pg_type.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "storage/predicate_internals.h"
#include "utils/array.h"
#include "utils/builtins.h"

Include dependency graph for lockfuncs.c:

Go to the source code of this file.

Data Structures
struct	PG_Lock_Status

Macros
#define	NUM_LOCK_STATUS_COLUMNS   16
#define	SET_LOCKTAG_INT64(tag, key64)
#define	SET_LOCKTAG_INT32(tag, key1, key2)    SET_LOCKTAG_ADVISORY(tag, MyDatabaseId, key1, key2, 2)

Functions
	StaticAssertDecl (lengthof(LockTagTypeNames)==(LOCKTAG_LAST_TYPE+1), "array length mismatch")
	StaticAssertDecl (lengthof(PredicateLockTagTypeNames)==(PREDLOCKTAG_TUPLE+1), "array length mismatch")
static Datum	VXIDGetDatum (BackendId bid, LocalTransactionId lxid)
Datum	pg_lock_status (PG_FUNCTION_ARGS)
Datum	pg_blocking_pids (PG_FUNCTION_ARGS)
Datum	pg_safe_snapshot_blocking_pids (PG_FUNCTION_ARGS)
Datum	pg_isolation_test_session_is_blocked (PG_FUNCTION_ARGS)
Datum	pg_advisory_lock_int8 (PG_FUNCTION_ARGS)
Datum	pg_advisory_xact_lock_int8 (PG_FUNCTION_ARGS)
Datum	pg_advisory_lock_shared_int8 (PG_FUNCTION_ARGS)
Datum	pg_advisory_xact_lock_shared_int8 (PG_FUNCTION_ARGS)
Datum	pg_try_advisory_lock_int8 (PG_FUNCTION_ARGS)
Datum	pg_try_advisory_xact_lock_int8 (PG_FUNCTION_ARGS)
Datum	pg_try_advisory_lock_shared_int8 (PG_FUNCTION_ARGS)
Datum	pg_try_advisory_xact_lock_shared_int8 (PG_FUNCTION_ARGS)
Datum	pg_advisory_unlock_int8 (PG_FUNCTION_ARGS)
Datum	pg_advisory_unlock_shared_int8 (PG_FUNCTION_ARGS)
Datum	pg_advisory_lock_int4 (PG_FUNCTION_ARGS)
Datum	pg_advisory_xact_lock_int4 (PG_FUNCTION_ARGS)
Datum	pg_advisory_lock_shared_int4 (PG_FUNCTION_ARGS)
Datum	pg_advisory_xact_lock_shared_int4 (PG_FUNCTION_ARGS)
Datum	pg_try_advisory_lock_int4 (PG_FUNCTION_ARGS)
Datum	pg_try_advisory_xact_lock_int4 (PG_FUNCTION_ARGS)
Datum	pg_try_advisory_lock_shared_int4 (PG_FUNCTION_ARGS)
Datum	pg_try_advisory_xact_lock_shared_int4 (PG_FUNCTION_ARGS)
Datum	pg_advisory_unlock_int4 (PG_FUNCTION_ARGS)
Datum	pg_advisory_unlock_shared_int4 (PG_FUNCTION_ARGS)
Datum	pg_advisory_unlock_all (PG_FUNCTION_ARGS)

Variables
const char *const	LockTagTypeNames []
static const char *const	PredicateLockTagTypeNames []

Macro Definition Documentation

NUM_LOCK_STATUS_COLUMNS

#define NUM_LOCK_STATUS_COLUMNS   16

Definition at line 67 of file lockfuncs.c.

SET_LOCKTAG_INT32

#define SET_LOCKTAG_INT32	(		tag,
			key1,
			key2
	)		SET_LOCKTAG_ADVISORY(tag, MyDatabaseId, key1, key2, 2)

Definition at line 697 of file lockfuncs.c.

SET_LOCKTAG_INT64

#define SET_LOCKTAG_INT64	(		tag,
			key64
	)

Value:

    SET_LOCKTAG_ADVISORY(tag, \
                         MyDatabaseId, \
                         (uint32) ((key64) >> 32), \
                         (uint32) (key64), \
                         1)

Definition at line 691 of file lockfuncs.c.

Function Documentation

pg_advisory_lock_int4()

Datum pg_advisory_lock_int4

(

PG_FUNCTION_ARGS

)

Definition at line 886 of file lockfuncs.c.

{
    int32       key1 = PG_GETARG_INT32(0);
    int32       key2 = PG_GETARG_INT32(1);
    LOCKTAG     tag;
 
    SET_LOCKTAG_INT32(tag, key1, key2);
 
    (void) LockAcquire(&tag, ExclusiveLock, true, false);
 
    PG_RETURN_VOID();
}

References ExclusiveLock, LockAcquire(), PG_GETARG_INT32, PG_RETURN_VOID, and SET_LOCKTAG_INT32.

pg_advisory_lock_int8()

Datum pg_advisory_lock_int8

(

PG_FUNCTION_ARGS

)

Definition at line 704 of file lockfuncs.c.

{
    int64       key = PG_GETARG_INT64(0);
    LOCKTAG     tag;
 
    SET_LOCKTAG_INT64(tag, key);
 
    (void) LockAcquire(&tag, ExclusiveLock, true, false);
 
    PG_RETURN_VOID();
}

References ExclusiveLock, sort-test::key, LockAcquire(), PG_GETARG_INT64, PG_RETURN_VOID, and SET_LOCKTAG_INT64.

Referenced by delay_execution_planner().

pg_advisory_lock_shared_int4()

Datum pg_advisory_lock_shared_int4

(

PG_FUNCTION_ARGS

)

Definition at line 921 of file lockfuncs.c.

{
    int32       key1 = PG_GETARG_INT32(0);
    int32       key2 = PG_GETARG_INT32(1);
    LOCKTAG     tag;
 
    SET_LOCKTAG_INT32(tag, key1, key2);
 
    (void) LockAcquire(&tag, ShareLock, true, false);
 
    PG_RETURN_VOID();
}

References LockAcquire(), PG_GETARG_INT32, PG_RETURN_VOID, SET_LOCKTAG_INT32, and ShareLock.

pg_advisory_lock_shared_int8()

Datum pg_advisory_lock_shared_int8

(

PG_FUNCTION_ARGS

)

Definition at line 737 of file lockfuncs.c.

{
    int64       key = PG_GETARG_INT64(0);
    LOCKTAG     tag;
 
    SET_LOCKTAG_INT64(tag, key);
 
    (void) LockAcquire(&tag, ShareLock, true, false);
 
    PG_RETURN_VOID();
}

References sort-test::key, LockAcquire(), PG_GETARG_INT64, PG_RETURN_VOID, SET_LOCKTAG_INT64, and ShareLock.

pg_advisory_unlock_all()

Datum pg_advisory_unlock_all

(

PG_FUNCTION_ARGS

)

Definition at line 1078 of file lockfuncs.c.

{
    LockReleaseSession(USER_LOCKMETHOD);
 
    PG_RETURN_VOID();
}

References LockReleaseSession(), PG_RETURN_VOID, and USER_LOCKMETHOD.

pg_advisory_unlock_int4()

Datum pg_advisory_unlock_int4

(

PG_FUNCTION_ARGS

)

Definition at line 1040 of file lockfuncs.c.

{
    int32       key1 = PG_GETARG_INT32(0);
    int32       key2 = PG_GETARG_INT32(1);
    LOCKTAG     tag;
    bool        res;
 
    SET_LOCKTAG_INT32(tag, key1, key2);
 
    res = LockRelease(&tag, ExclusiveLock, true);
 
    PG_RETURN_BOOL(res);
}

References ExclusiveLock, LockRelease(), PG_GETARG_INT32, PG_RETURN_BOOL, res, and SET_LOCKTAG_INT32.

pg_advisory_unlock_int8()

Datum pg_advisory_unlock_int8

(

PG_FUNCTION_ARGS

)

Definition at line 850 of file lockfuncs.c.

{
    int64       key = PG_GETARG_INT64(0);
    LOCKTAG     tag;
    bool        res;
 
    SET_LOCKTAG_INT64(tag, key);
 
    res = LockRelease(&tag, ExclusiveLock, true);
 
    PG_RETURN_BOOL(res);
}

References ExclusiveLock, sort-test::key, LockRelease(), PG_GETARG_INT64, PG_RETURN_BOOL, res, and SET_LOCKTAG_INT64.

Referenced by delay_execution_planner().

pg_advisory_unlock_shared_int4()

Datum pg_advisory_unlock_shared_int4

(

PG_FUNCTION_ARGS

)

Definition at line 1060 of file lockfuncs.c.

{
    int32       key1 = PG_GETARG_INT32(0);
    int32       key2 = PG_GETARG_INT32(1);
    LOCKTAG     tag;
    bool        res;
 
    SET_LOCKTAG_INT32(tag, key1, key2);
 
    res = LockRelease(&tag, ShareLock, true);
 
    PG_RETURN_BOOL(res);
}

References LockRelease(), PG_GETARG_INT32, PG_RETURN_BOOL, res, SET_LOCKTAG_INT32, and ShareLock.

pg_advisory_unlock_shared_int8()

Datum pg_advisory_unlock_shared_int8

(

PG_FUNCTION_ARGS

)

Definition at line 869 of file lockfuncs.c.

{
    int64       key = PG_GETARG_INT64(0);
    LOCKTAG     tag;
    bool        res;
 
    SET_LOCKTAG_INT64(tag, key);
 
    res = LockRelease(&tag, ShareLock, true);
 
    PG_RETURN_BOOL(res);
}

References sort-test::key, LockRelease(), PG_GETARG_INT64, PG_RETURN_BOOL, res, SET_LOCKTAG_INT64, and ShareLock.

pg_advisory_xact_lock_int4()

Datum pg_advisory_xact_lock_int4

(

PG_FUNCTION_ARGS

)

Definition at line 904 of file lockfuncs.c.

{
    int32       key1 = PG_GETARG_INT32(0);
    int32       key2 = PG_GETARG_INT32(1);
    LOCKTAG     tag;
 
    SET_LOCKTAG_INT32(tag, key1, key2);
 
    (void) LockAcquire(&tag, ExclusiveLock, false, false);
 
    PG_RETURN_VOID();
}

References ExclusiveLock, LockAcquire(), PG_GETARG_INT32, PG_RETURN_VOID, and SET_LOCKTAG_INT32.

pg_advisory_xact_lock_int8()

Datum pg_advisory_xact_lock_int8

(

PG_FUNCTION_ARGS

)

Definition at line 721 of file lockfuncs.c.

{
    int64       key = PG_GETARG_INT64(0);
    LOCKTAG     tag;
 
    SET_LOCKTAG_INT64(tag, key);
 
    (void) LockAcquire(&tag, ExclusiveLock, false, false);
 
    PG_RETURN_VOID();
}

References ExclusiveLock, sort-test::key, LockAcquire(), PG_GETARG_INT64, PG_RETURN_VOID, and SET_LOCKTAG_INT64.

pg_advisory_xact_lock_shared_int4()

Datum pg_advisory_xact_lock_shared_int4

(

PG_FUNCTION_ARGS

)

Definition at line 939 of file lockfuncs.c.

{
    int32       key1 = PG_GETARG_INT32(0);
    int32       key2 = PG_GETARG_INT32(1);
    LOCKTAG     tag;
 
    SET_LOCKTAG_INT32(tag, key1, key2);
 
    (void) LockAcquire(&tag, ShareLock, false, false);
 
    PG_RETURN_VOID();
}

References LockAcquire(), PG_GETARG_INT32, PG_RETURN_VOID, SET_LOCKTAG_INT32, and ShareLock.

pg_advisory_xact_lock_shared_int8()

Datum pg_advisory_xact_lock_shared_int8

(

PG_FUNCTION_ARGS

)

Definition at line 754 of file lockfuncs.c.

{
    int64       key = PG_GETARG_INT64(0);
    LOCKTAG     tag;
 
    SET_LOCKTAG_INT64(tag, key);
 
    (void) LockAcquire(&tag, ShareLock, false, false);
 
    PG_RETURN_VOID();
}

References sort-test::key, LockAcquire(), PG_GETARG_INT64, PG_RETURN_VOID, SET_LOCKTAG_INT64, and ShareLock.

pg_blocking_pids()

Datum pg_blocking_pids

(

PG_FUNCTION_ARGS

)

Definition at line 466 of file lockfuncs.c.

{
    int         blocked_pid = PG_GETARG_INT32(0);
    Datum      *arrayelems;
    int         narrayelems;
    BlockedProcsData *lockData; /* state data from lmgr */
    int         i,
                j;
 
    /* Collect a snapshot of lock manager state */
    lockData = GetBlockerStatusData(blocked_pid);
 
    /* We can't need more output entries than there are reported PROCLOCKs */
    arrayelems = (Datum *) palloc(lockData->nlocks * sizeof(Datum));
    narrayelems = 0;
 
    /* For each blocked proc in the lock group ... */
    for (i = 0; i < lockData->nprocs; i++)
    {
        BlockedProcData *bproc = &lockData->procs[i];
        LockInstanceData *instances = &lockData->locks[bproc->first_lock];
        int        *preceding_waiters = &lockData->waiter_pids[bproc->first_waiter];
        LockInstanceData *blocked_instance;
        LockMethod  lockMethodTable;
        int         conflictMask;
 
        /*
         * Locate the blocked proc's own entry in the LockInstanceData array.
         * There should be exactly one matching entry.
         */
        blocked_instance = NULL;
        for (j = 0; j < bproc->num_locks; j++)
        {
            LockInstanceData *instance = &(instances[j]);
 
            if (instance->pid == bproc->pid)
            {
                Assert(blocked_instance == NULL);
                blocked_instance = instance;
            }
        }
        Assert(blocked_instance != NULL);
 
        lockMethodTable = GetLockTagsMethodTable(&(blocked_instance->locktag));
        conflictMask = lockMethodTable->conflictTab[blocked_instance->waitLockMode];
 
        /* Now scan the PROCLOCK data for conflicting procs */
        for (j = 0; j < bproc->num_locks; j++)
        {
            LockInstanceData *instance = &(instances[j]);
 
            /* A proc never blocks itself, so ignore that entry */
            if (instance == blocked_instance)
                continue;
            /* Members of same lock group never block each other, either */
            if (instance->leaderPid == blocked_instance->leaderPid)
                continue;
 
            if (conflictMask & instance->holdMask)
            {
                /* hard block: blocked by lock already held by this entry */
            }
            else if (instance->waitLockMode != NoLock &&
                     (conflictMask & LOCKBIT_ON(instance->waitLockMode)))
            {
                /* conflict in lock requests; who's in front in wait queue? */
                bool        ahead = false;
                int         k;
 
                for (k = 0; k < bproc->num_waiters; k++)
                {
                    if (preceding_waiters[k] == instance->pid)
                    {
                        /* soft block: this entry is ahead of blocked proc */
                        ahead = true;
                        break;
                    }
                }
                if (!ahead)
                    continue;   /* not blocked by this entry */
            }
            else
            {
                /* not blocked by this entry */
                continue;
            }
 
            /* blocked by this entry, so emit a record */
            arrayelems[narrayelems++] = Int32GetDatum(instance->leaderPid);
        }
    }
 
    /* Assert we didn't overrun arrayelems[] */
    Assert(narrayelems <= lockData->nlocks);
 
    PG_RETURN_ARRAYTYPE_P(construct_array_builtin(arrayelems, narrayelems, INT4OID));
}

References Assert(), LockMethodData::conflictTab, construct_array_builtin(), BlockedProcData::first_lock, BlockedProcData::first_waiter, GetBlockerStatusData(), GetLockTagsMethodTable(), LockInstanceData::holdMask, i, Int32GetDatum(), j, LockInstanceData::leaderPid, LOCKBIT_ON, BlockedProcsData::locks, LockInstanceData::locktag, BlockedProcsData::nlocks, NoLock, BlockedProcsData::nprocs, BlockedProcData::num_locks, BlockedProcData::num_waiters, palloc(), PG_GETARG_INT32, PG_RETURN_ARRAYTYPE_P, LockInstanceData::pid, BlockedProcData::pid, BlockedProcsData::procs, BlockedProcsData::waiter_pids, and LockInstanceData::waitLockMode.

Referenced by pg_isolation_test_session_is_blocked().

pg_isolation_test_session_is_blocked()

Datum pg_isolation_test_session_is_blocked

(

PG_FUNCTION_ARGS

)

Definition at line 615 of file lockfuncs.c.

{
    int         blocked_pid = PG_GETARG_INT32(0);
    ArrayType  *interesting_pids_a = PG_GETARG_ARRAYTYPE_P(1);
    ArrayType  *blocking_pids_a;
    int32      *interesting_pids;
    int32      *blocking_pids;
    int         num_interesting_pids;
    int         num_blocking_pids;
    int         dummy;
    int         i,
                j;
 
    /* Validate the passed-in array */
    Assert(ARR_ELEMTYPE(interesting_pids_a) == INT4OID);
    if (array_contains_nulls(interesting_pids_a))
        elog(ERROR, "array must not contain nulls");
    interesting_pids = (int32 *) ARR_DATA_PTR(interesting_pids_a);
    num_interesting_pids = ArrayGetNItems(ARR_NDIM(interesting_pids_a),
                                          ARR_DIMS(interesting_pids_a));
 
    /*
     * Get the PIDs of all sessions blocking the given session's attempt to
     * acquire heavyweight locks.
     */
    blocking_pids_a =
        DatumGetArrayTypeP(DirectFunctionCall1(pg_blocking_pids, blocked_pid));
 
    Assert(ARR_ELEMTYPE(blocking_pids_a) == INT4OID);
    Assert(!array_contains_nulls(blocking_pids_a));
    blocking_pids = (int32 *) ARR_DATA_PTR(blocking_pids_a);
    num_blocking_pids = ArrayGetNItems(ARR_NDIM(blocking_pids_a),
                                       ARR_DIMS(blocking_pids_a));
 
    /*
     * Check if any of these are in the list of interesting PIDs, that being
     * the sessions that the isolation tester is running.  We don't use
     * "arrayoverlaps" here, because it would lead to cache lookups and one of
     * our goals is to run quickly with debug_discard_caches > 0.  We expect
     * blocking_pids to be usually empty and otherwise a very small number in
     * isolation tester cases, so make that the outer loop of a naive search
     * for a match.
     */
    for (i = 0; i < num_blocking_pids; i++)
        for (j = 0; j < num_interesting_pids; j++)
        {
            if (blocking_pids[i] == interesting_pids[j])
                PG_RETURN_BOOL(true);
        }
 
    /*
     * Check if blocked_pid is waiting for a safe snapshot.  We could in
     * theory check the resulting array of blocker PIDs against the
     * interesting PIDs list, but since there is no danger of autovacuum
     * blocking GetSafeSnapshot there seems to be no point in expending cycles
     * on allocating a buffer and searching for overlap; so it's presently
     * sufficient for the isolation tester's purposes to use a single element
     * buffer and check if the number of safe snapshot blockers is non-zero.
     */
    if (GetSafeSnapshotBlockingPids(blocked_pid, &dummy, 1) > 0)
        PG_RETURN_BOOL(true);
 
    PG_RETURN_BOOL(false);
}

References ARR_DATA_PTR, ARR_DIMS, ARR_ELEMTYPE, ARR_NDIM, array_contains_nulls(), ArrayGetNItems(), Assert(), DatumGetArrayTypeP, DirectFunctionCall1, elog(), ERROR, GetSafeSnapshotBlockingPids(), i, j, pg_blocking_pids(), PG_GETARG_ARRAYTYPE_P, PG_GETARG_INT32, and PG_RETURN_BOOL.

pg_lock_status()

Datum pg_lock_status

(

PG_FUNCTION_ARGS

)

Definition at line 93 of file lockfuncs.c.

{
    FuncCallContext *funcctx;
    PG_Lock_Status *mystatus;
    LockData   *lockData;
    PredicateLockData *predLockData;
 
    if (SRF_IS_FIRSTCALL())
    {
        TupleDesc   tupdesc;
        MemoryContext oldcontext;
 
        /* create a function context for cross-call persistence */
        funcctx = SRF_FIRSTCALL_INIT();
 
        /*
         * switch to memory context appropriate for multiple function calls
         */
        oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
 
        /* build tupdesc for result tuples */
        /* this had better match function's declaration in pg_proc.h */
        tupdesc = CreateTemplateTupleDesc(NUM_LOCK_STATUS_COLUMNS);
        TupleDescInitEntry(tupdesc, (AttrNumber) 1, "locktype",
                           TEXTOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 2, "database",
                           OIDOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 3, "relation",
                           OIDOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 4, "page",
                           INT4OID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 5, "tuple",
                           INT2OID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 6, "virtualxid",
                           TEXTOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 7, "transactionid",
                           XIDOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 8, "classid",
                           OIDOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 9, "objid",
                           OIDOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 10, "objsubid",
                           INT2OID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 11, "virtualtransaction",
                           TEXTOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 12, "pid",
                           INT4OID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 13, "mode",
                           TEXTOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 14, "granted",
                           BOOLOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 15, "fastpath",
                           BOOLOID, -1, 0);
        TupleDescInitEntry(tupdesc, (AttrNumber) 16, "waitstart",
                           TIMESTAMPTZOID, -1, 0);
 
        funcctx->tuple_desc = BlessTupleDesc(tupdesc);
 
        /*
         * Collect all the locking information that we will format and send
         * out as a result set.
         */
        mystatus = (PG_Lock_Status *) palloc(sizeof(PG_Lock_Status));
        funcctx->user_fctx = (void *) mystatus;
 
        mystatus->lockData = GetLockStatusData();
        mystatus->currIdx = 0;
        mystatus->predLockData = GetPredicateLockStatusData();
        mystatus->predLockIdx = 0;
 
        MemoryContextSwitchTo(oldcontext);
    }
 
    funcctx = SRF_PERCALL_SETUP();
    mystatus = (PG_Lock_Status *) funcctx->user_fctx;
    lockData = mystatus->lockData;
 
    while (mystatus->currIdx < lockData->nelements)
    {
        bool        granted;
        LOCKMODE    mode = 0;
        const char *locktypename;
        char        tnbuf[32];
        Datum       values[NUM_LOCK_STATUS_COLUMNS] = {0};
        bool        nulls[NUM_LOCK_STATUS_COLUMNS] = {0};
        HeapTuple   tuple;
        Datum       result;
        LockInstanceData *instance;
 
        instance = &(lockData->locks[mystatus->currIdx]);
 
        /*
         * Look to see if there are any held lock modes in this PROCLOCK. If
         * so, report, and destructively modify lockData so we don't report
         * again.
         */
        granted = false;
        if (instance->holdMask)
        {
            for (mode = 0; mode < MAX_LOCKMODES; mode++)
            {
                if (instance->holdMask & LOCKBIT_ON(mode))
                {
                    granted = true;
                    instance->holdMask &= LOCKBIT_OFF(mode);
                    break;
                }
            }
        }
 
        /*
         * If no (more) held modes to report, see if PROC is waiting for a
         * lock on this lock.
         */
        if (!granted)
        {
            if (instance->waitLockMode != NoLock)
            {
                /* Yes, so report it with proper mode */
                mode = instance->waitLockMode;
 
                /*
                 * We are now done with this PROCLOCK, so advance pointer to
                 * continue with next one on next call.
                 */
                mystatus->currIdx++;
            }
            else
            {
                /*
                 * Okay, we've displayed all the locks associated with this
                 * PROCLOCK, proceed to the next one.
                 */
                mystatus->currIdx++;
                continue;
            }
        }
 
        /*
         * Form tuple with appropriate data.
         */
 
        if (instance->locktag.locktag_type <= LOCKTAG_LAST_TYPE)
            locktypename = LockTagTypeNames[instance->locktag.locktag_type];
        else
        {
            snprintf(tnbuf, sizeof(tnbuf), "unknown %d",
                     (int) instance->locktag.locktag_type);
            locktypename = tnbuf;
        }
        values[0] = CStringGetTextDatum(locktypename);
 
        switch ((LockTagType) instance->locktag.locktag_type)
        {
            case LOCKTAG_RELATION:
            case LOCKTAG_RELATION_EXTEND:
                values[1] = ObjectIdGetDatum(instance->locktag.locktag_field1);
                values[2] = ObjectIdGetDatum(instance->locktag.locktag_field2);
                nulls[3] = true;
                nulls[4] = true;
                nulls[5] = true;
                nulls[6] = true;
                nulls[7] = true;
                nulls[8] = true;
                nulls[9] = true;
                break;
            case LOCKTAG_DATABASE_FROZEN_IDS:
                values[1] = ObjectIdGetDatum(instance->locktag.locktag_field1);
                nulls[2] = true;
                nulls[3] = true;
                nulls[4] = true;
                nulls[5] = true;
                nulls[6] = true;
                nulls[7] = true;
                nulls[8] = true;
                nulls[9] = true;
                break;
            case LOCKTAG_PAGE:
                values[1] = ObjectIdGetDatum(instance->locktag.locktag_field1);
                values[2] = ObjectIdGetDatum(instance->locktag.locktag_field2);
                values[3] = UInt32GetDatum(instance->locktag.locktag_field3);
                nulls[4] = true;
                nulls[5] = true;
                nulls[6] = true;
                nulls[7] = true;
                nulls[8] = true;
                nulls[9] = true;
                break;
            case LOCKTAG_TUPLE:
                values[1] = ObjectIdGetDatum(instance->locktag.locktag_field1);
                values[2] = ObjectIdGetDatum(instance->locktag.locktag_field2);
                values[3] = UInt32GetDatum(instance->locktag.locktag_field3);
                values[4] = UInt16GetDatum(instance->locktag.locktag_field4);
                nulls[5] = true;
                nulls[6] = true;
                nulls[7] = true;
                nulls[8] = true;
                nulls[9] = true;
                break;
            case LOCKTAG_TRANSACTION:
                values[6] =
                    TransactionIdGetDatum(instance->locktag.locktag_field1);
                nulls[1] = true;
                nulls[2] = true;
                nulls[3] = true;
                nulls[4] = true;
                nulls[5] = true;
                nulls[7] = true;
                nulls[8] = true;
                nulls[9] = true;
                break;
            case LOCKTAG_VIRTUALTRANSACTION:
                values[5] = VXIDGetDatum(instance->locktag.locktag_field1,
                                         instance->locktag.locktag_field2);
                nulls[1] = true;
                nulls[2] = true;
                nulls[3] = true;
                nulls[4] = true;
                nulls[6] = true;
                nulls[7] = true;
                nulls[8] = true;
                nulls[9] = true;
                break;
            case LOCKTAG_SPECULATIVE_TOKEN:
                values[6] =
                    TransactionIdGetDatum(instance->locktag.locktag_field1);
                values[8] = ObjectIdGetDatum(instance->locktag.locktag_field2);
                nulls[1] = true;
                nulls[2] = true;
                nulls[3] = true;
                nulls[4] = true;
                nulls[5] = true;
                nulls[7] = true;
                nulls[9] = true;
                break;
            case LOCKTAG_APPLY_TRANSACTION:
                values[1] = ObjectIdGetDatum(instance->locktag.locktag_field1);
                values[8] = ObjectIdGetDatum(instance->locktag.locktag_field2);
                values[6] = ObjectIdGetDatum(instance->locktag.locktag_field3);
                values[9] = Int16GetDatum(instance->locktag.locktag_field4);
                nulls[2] = true;
                nulls[3] = true;
                nulls[4] = true;
                nulls[5] = true;
                nulls[7] = true;
                break;
            case LOCKTAG_OBJECT:
            case LOCKTAG_USERLOCK:
            case LOCKTAG_ADVISORY:
            default:            /* treat unknown locktags like OBJECT */
                values[1] = ObjectIdGetDatum(instance->locktag.locktag_field1);
                values[7] = ObjectIdGetDatum(instance->locktag.locktag_field2);
                values[8] = ObjectIdGetDatum(instance->locktag.locktag_field3);
                values[9] = Int16GetDatum(instance->locktag.locktag_field4);
                nulls[2] = true;
                nulls[3] = true;
                nulls[4] = true;
                nulls[5] = true;
                nulls[6] = true;
                break;
        }
 
        values[10] = VXIDGetDatum(instance->backend, instance->lxid);
        if (instance->pid != 0)
            values[11] = Int32GetDatum(instance->pid);
        else
            nulls[11] = true;
        values[12] = CStringGetTextDatum(GetLockmodeName(instance->locktag.locktag_lockmethodid, mode));
        values[13] = BoolGetDatum(granted);
        values[14] = BoolGetDatum(instance->fastpath);
        if (!granted && instance->waitStart != 0)
            values[15] = TimestampTzGetDatum(instance->waitStart);
        else
            nulls[15] = true;
 
        tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
        result = HeapTupleGetDatum(tuple);
        SRF_RETURN_NEXT(funcctx, result);
    }
 
    /*
     * Have returned all regular locks. Now start on the SIREAD predicate
     * locks.
     */
    predLockData = mystatus->predLockData;
    if (mystatus->predLockIdx < predLockData->nelements)
    {
        PredicateLockTargetType lockType;
 
        PREDICATELOCKTARGETTAG *predTag = &(predLockData->locktags[mystatus->predLockIdx]);
        SERIALIZABLEXACT *xact = &(predLockData->xacts[mystatus->predLockIdx]);
        Datum       values[NUM_LOCK_STATUS_COLUMNS] = {0};
        bool        nulls[NUM_LOCK_STATUS_COLUMNS] = {0};
        HeapTuple   tuple;
        Datum       result;
 
        mystatus->predLockIdx++;
 
        /*
         * Form tuple with appropriate data.
         */
 
        /* lock type */
        lockType = GET_PREDICATELOCKTARGETTAG_TYPE(*predTag);
 
        values[0] = CStringGetTextDatum(PredicateLockTagTypeNames[lockType]);
 
        /* lock target */
        values[1] = GET_PREDICATELOCKTARGETTAG_DB(*predTag);
        values[2] = GET_PREDICATELOCKTARGETTAG_RELATION(*predTag);
        if (lockType == PREDLOCKTAG_TUPLE)
            values[4] = GET_PREDICATELOCKTARGETTAG_OFFSET(*predTag);
        else
            nulls[4] = true;
        if ((lockType == PREDLOCKTAG_TUPLE) ||
            (lockType == PREDLOCKTAG_PAGE))
            values[3] = GET_PREDICATELOCKTARGETTAG_PAGE(*predTag);
        else
            nulls[3] = true;
 
        /* these fields are targets for other types of locks */
        nulls[5] = true;        /* virtualxid */
        nulls[6] = true;        /* transactionid */
        nulls[7] = true;        /* classid */
        nulls[8] = true;        /* objid */
        nulls[9] = true;        /* objsubid */
 
        /* lock holder */
        values[10] = VXIDGetDatum(xact->vxid.backendId,
                                  xact->vxid.localTransactionId);
        if (xact->pid != 0)
            values[11] = Int32GetDatum(xact->pid);
        else
            nulls[11] = true;
 
        /*
         * Lock mode. Currently all predicate locks are SIReadLocks, which are
         * always held (never waiting) and have no fast path
         */
        values[12] = CStringGetTextDatum("SIReadLock");
        values[13] = BoolGetDatum(true);
        values[14] = BoolGetDatum(false);
        nulls[15] = true;
 
        tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
        result = HeapTupleGetDatum(tuple);
        SRF_RETURN_NEXT(funcctx, result);
    }
 
    SRF_RETURN_DONE(funcctx);
}

References LockInstanceData::backend, VirtualTransactionId::backendId, BlessTupleDesc(), BoolGetDatum(), CreateTemplateTupleDesc(), CStringGetTextDatum, PG_Lock_Status::currIdx, LockInstanceData::fastpath, GET_PREDICATELOCKTARGETTAG_DB, GET_PREDICATELOCKTARGETTAG_OFFSET, GET_PREDICATELOCKTARGETTAG_PAGE, GET_PREDICATELOCKTARGETTAG_RELATION, GET_PREDICATELOCKTARGETTAG_TYPE, GetLockmodeName(), GetLockStatusData(), GetPredicateLockStatusData(), heap_form_tuple(), HeapTupleGetDatum(), LockInstanceData::holdMask, Int16GetDatum(), Int32GetDatum(), VirtualTransactionId::localTransactionId, LOCKBIT_OFF, LOCKBIT_ON, PG_Lock_Status::lockData, LockData::locks, LockInstanceData::locktag, LOCKTAG_ADVISORY, LOCKTAG_APPLY_TRANSACTION, LOCKTAG_DATABASE_FROZEN_IDS, LOCKTAG::locktag_field1, LOCKTAG::locktag_field2, LOCKTAG::locktag_field3, LOCKTAG::locktag_field4, LOCKTAG_LAST_TYPE, LOCKTAG::locktag_lockmethodid, LOCKTAG_OBJECT, LOCKTAG_PAGE, LOCKTAG_RELATION, LOCKTAG_RELATION_EXTEND, LOCKTAG_SPECULATIVE_TOKEN, LOCKTAG_TRANSACTION, LOCKTAG_TUPLE, LOCKTAG::locktag_type, LOCKTAG_USERLOCK, LOCKTAG_VIRTUALTRANSACTION, PredicateLockData::locktags, LockTagTypeNames, LockInstanceData::lxid, MAX_LOCKMODES, MemoryContextSwitchTo(), mode, FuncCallContext::multi_call_memory_ctx, LockData::nelements, PredicateLockData::nelements, NoLock, NUM_LOCK_STATUS_COLUMNS, ObjectIdGetDatum(), palloc(), LockInstanceData::pid, SERIALIZABLEXACT::pid, PredicateLockTagTypeNames, PG_Lock_Status::predLockData, PG_Lock_Status::predLockIdx, PREDLOCKTAG_PAGE, PREDLOCKTAG_TUPLE, snprintf, SRF_FIRSTCALL_INIT, SRF_IS_FIRSTCALL, SRF_PERCALL_SETUP, SRF_RETURN_DONE, SRF_RETURN_NEXT, TimestampTzGetDatum(), TransactionIdGetDatum(), FuncCallContext::tuple_desc, TupleDescInitEntry(), UInt16GetDatum(), UInt32GetDatum(), FuncCallContext::user_fctx, values, SERIALIZABLEXACT::vxid, VXIDGetDatum(), LockInstanceData::waitLockMode, LockInstanceData::waitStart, while(), and PredicateLockData::xacts.

pg_safe_snapshot_blocking_pids()

Datum pg_safe_snapshot_blocking_pids

(

PG_FUNCTION_ARGS

)

Definition at line 573 of file lockfuncs.c.

{
    int         blocked_pid = PG_GETARG_INT32(0);
    int        *blockers;
    int         num_blockers;
    Datum      *blocker_datums;
 
    /* A buffer big enough for any possible blocker list without truncation */
    blockers = (int *) palloc(MaxBackends * sizeof(int));
 
    /* Collect a snapshot of processes waited for by GetSafeSnapshot */
    num_blockers =
        GetSafeSnapshotBlockingPids(blocked_pid, blockers, MaxBackends);
 
    /* Convert int array to Datum array */
    if (num_blockers > 0)
    {
        int         i;
 
        blocker_datums = (Datum *) palloc(num_blockers * sizeof(Datum));
        for (i = 0; i < num_blockers; ++i)
            blocker_datums[i] = Int32GetDatum(blockers[i]);
    }
    else
        blocker_datums = NULL;
 
    PG_RETURN_ARRAYTYPE_P(construct_array_builtin(blocker_datums, num_blockers, INT4OID));
}

References construct_array_builtin(), GetSafeSnapshotBlockingPids(), i, Int32GetDatum(), MaxBackends, palloc(), PG_GETARG_INT32, and PG_RETURN_ARRAYTYPE_P.

pg_try_advisory_lock_int4()

Datum pg_try_advisory_lock_int4

(

PG_FUNCTION_ARGS

)

Definition at line 958 of file lockfuncs.c.

{
    int32       key1 = PG_GETARG_INT32(0);
    int32       key2 = PG_GETARG_INT32(1);
    LOCKTAG     tag;
    LockAcquireResult res;
 
    SET_LOCKTAG_INT32(tag, key1, key2);
 
    res = LockAcquire(&tag, ExclusiveLock, true, true);
 
    PG_RETURN_BOOL(res != LOCKACQUIRE_NOT_AVAIL);
}

References ExclusiveLock, LockAcquire(), LOCKACQUIRE_NOT_AVAIL, PG_GETARG_INT32, PG_RETURN_BOOL, res, and SET_LOCKTAG_INT32.

pg_try_advisory_lock_int8()

Datum pg_try_advisory_lock_int8

(

PG_FUNCTION_ARGS

)

Definition at line 772 of file lockfuncs.c.

{
    int64       key = PG_GETARG_INT64(0);
    LOCKTAG     tag;
    LockAcquireResult res;
 
    SET_LOCKTAG_INT64(tag, key);
 
    res = LockAcquire(&tag, ExclusiveLock, true, true);
 
    PG_RETURN_BOOL(res != LOCKACQUIRE_NOT_AVAIL);
}

References ExclusiveLock, sort-test::key, LockAcquire(), LOCKACQUIRE_NOT_AVAIL, PG_GETARG_INT64, PG_RETURN_BOOL, res, and SET_LOCKTAG_INT64.

pg_try_advisory_lock_shared_int4()

Datum pg_try_advisory_lock_shared_int4

(

PG_FUNCTION_ARGS

)

Definition at line 999 of file lockfuncs.c.

{
    int32       key1 = PG_GETARG_INT32(0);
    int32       key2 = PG_GETARG_INT32(1);
    LOCKTAG     tag;
    LockAcquireResult res;
 
    SET_LOCKTAG_INT32(tag, key1, key2);
 
    res = LockAcquire(&tag, ShareLock, true, true);
 
    PG_RETURN_BOOL(res != LOCKACQUIRE_NOT_AVAIL);
}

References LockAcquire(), LOCKACQUIRE_NOT_AVAIL, PG_GETARG_INT32, PG_RETURN_BOOL, res, SET_LOCKTAG_INT32, and ShareLock.

pg_try_advisory_lock_shared_int8()

Datum pg_try_advisory_lock_shared_int8

(

PG_FUNCTION_ARGS

)

Definition at line 811 of file lockfuncs.c.

{
    int64       key = PG_GETARG_INT64(0);
    LOCKTAG     tag;
    LockAcquireResult res;
 
    SET_LOCKTAG_INT64(tag, key);
 
    res = LockAcquire(&tag, ShareLock, true, true);
 
    PG_RETURN_BOOL(res != LOCKACQUIRE_NOT_AVAIL);
}

References sort-test::key, LockAcquire(), LOCKACQUIRE_NOT_AVAIL, PG_GETARG_INT64, PG_RETURN_BOOL, res, SET_LOCKTAG_INT64, and ShareLock.

pg_try_advisory_xact_lock_int4()

Datum pg_try_advisory_xact_lock_int4

(

PG_FUNCTION_ARGS

)

Definition at line 979 of file lockfuncs.c.

{
    int32       key1 = PG_GETARG_INT32(0);
    int32       key2 = PG_GETARG_INT32(1);
    LOCKTAG     tag;
    LockAcquireResult res;
 
    SET_LOCKTAG_INT32(tag, key1, key2);
 
    res = LockAcquire(&tag, ExclusiveLock, false, true);
 
    PG_RETURN_BOOL(res != LOCKACQUIRE_NOT_AVAIL);
}

References ExclusiveLock, LockAcquire(), LOCKACQUIRE_NOT_AVAIL, PG_GETARG_INT32, PG_RETURN_BOOL, res, and SET_LOCKTAG_INT32.

pg_try_advisory_xact_lock_int8()

Datum pg_try_advisory_xact_lock_int8

(

PG_FUNCTION_ARGS

)

Definition at line 792 of file lockfuncs.c.

{
    int64       key = PG_GETARG_INT64(0);
    LOCKTAG     tag;
    LockAcquireResult res;
 
    SET_LOCKTAG_INT64(tag, key);
 
    res = LockAcquire(&tag, ExclusiveLock, false, true);
 
    PG_RETURN_BOOL(res != LOCKACQUIRE_NOT_AVAIL);
}

References ExclusiveLock, sort-test::key, LockAcquire(), LOCKACQUIRE_NOT_AVAIL, PG_GETARG_INT64, PG_RETURN_BOOL, res, and SET_LOCKTAG_INT64.

pg_try_advisory_xact_lock_shared_int4()

Datum pg_try_advisory_xact_lock_shared_int4

(

PG_FUNCTION_ARGS

)

Definition at line 1020 of file lockfuncs.c.

{
    int32       key1 = PG_GETARG_INT32(0);
    int32       key2 = PG_GETARG_INT32(1);
    LOCKTAG     tag;
    LockAcquireResult res;
 
    SET_LOCKTAG_INT32(tag, key1, key2);
 
    res = LockAcquire(&tag, ShareLock, false, true);
 
    PG_RETURN_BOOL(res != LOCKACQUIRE_NOT_AVAIL);
}

References LockAcquire(), LOCKACQUIRE_NOT_AVAIL, PG_GETARG_INT32, PG_RETURN_BOOL, res, SET_LOCKTAG_INT32, and ShareLock.

pg_try_advisory_xact_lock_shared_int8()

Datum pg_try_advisory_xact_lock_shared_int8

(

PG_FUNCTION_ARGS

)

Definition at line 831 of file lockfuncs.c.

{
    int64       key = PG_GETARG_INT64(0);
    LOCKTAG     tag;
    LockAcquireResult res;
 
    SET_LOCKTAG_INT64(tag, key);
 
    res = LockAcquire(&tag, ShareLock, false, true);
 
    PG_RETURN_BOOL(res != LOCKACQUIRE_NOT_AVAIL);
}

References sort-test::key, LockAcquire(), LOCKACQUIRE_NOT_AVAIL, PG_GETARG_INT64, PG_RETURN_BOOL, res, SET_LOCKTAG_INT64, and ShareLock.

StaticAssertDecl() [1/2]

StaticAssertDecl	(	lengthof(LockTagTypeNames)	= =(LOCKTAG_LAST_TYPE+1),
		"array length mismatch"
	)

StaticAssertDecl() [2/2]

StaticAssertDecl	(	lengthof(PredicateLockTagTypeNames)	= =(PREDLOCKTAG_TUPLE+1),
		"array length mismatch"
	)

VXIDGetDatum()

static Datum VXIDGetDatum ( BackendId  bid, LocalTransactionId  lxid  )

static

Definition at line 75 of file lockfuncs.c.

{
    /*
     * The representation is "<bid>/<lxid>", decimal and unsigned decimal
     * respectively.  Note that elog.c also knows how to format a vxid.
     */
    char        vxidstr[32];
 
    snprintf(vxidstr, sizeof(vxidstr), "%d/%u", bid, lxid);
 
    return CStringGetTextDatum(vxidstr);
}

References CStringGetTextDatum, and snprintf.

Referenced by pg_lock_status().

Variable Documentation

LockTagTypeNames

const char* const LockTagTypeNames[]

Initial value:

= {
    "relation",
    "extend",
    "frozenid",
    "page",
    "tuple",
    "transactionid",
    "virtualxid",
    "spectoken",
    "object",
    "userlock",
    "advisory",
    "applytransaction"
}

Definition at line 29 of file lockfuncs.c.

Referenced by GetLockNameFromTagType(), and pg_lock_status().

PredicateLockTagTypeNames

const char* const PredicateLockTagTypeNames[]

static

Initial value:

= {
    "relation",
    "page",
    "tuple"
}

Definition at line 48 of file lockfuncs.c.

Referenced by pg_lock_status().