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Add transaction-level advisory locks.

Browse Source 
They share the same locking namespace with the existing session-level
advisory locks, but they are automatically released at the end of the
current transaction and cannot be released explicitly via unlock
functions.

Marko Tiikkaja, reviewed by me.
pull/1/head
Itagaki Takahiro 15 years ago
parent 87bb2ade2c
commit 62c7bd31c8
14 changed files with 814 additions and 71 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 128
      doc/src/sgml/func.sgml
  2. 35
      doc/src/sgml/mvcc.sgml
  3. 11
      src/backend/storage/lmgr/README
  4. 101
      src/backend/storage/lmgr/lock.c
  5. 5
      src/backend/storage/lmgr/proc.c
  6. 154
      src/backend/utils/adt/lockfuncs.c
  7. 2
      src/include/catalog/catversion.h
  8. 16
      src/include/catalog/pg_proc.h
  9. 1
      src/include/storage/lock.h
  10. 8
      src/include/utils/builtins.h
  11. 275
      src/test/regress/expected/advisory_lock.out
  12. 2
      src/test/regress/parallel_schedule
  13. 1
      src/test/regress/serial_schedule
  14. 146
      src/test/regress/sql/advisory_lock.sql

128
doc/src/sgml/func.sgml
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@ -14623,91 +14623,147 @@ SELECT (pg_stat_file('filename')).modification;
<literal><function>pg_advisory_lock(<parameter>key</> <type>bigint</>)</function></literal>
</entry>
<entry><type>void</type></entry>
<entry>Obtain exclusive advisory lock</entry>
<entry>Obtain exclusive session level advisory lock</entry>
</row>
<row>
<entry>
<literal><function>pg_advisory_lock(<parameter>key1</> <type>int</>, <parameter>key2</> <type>int</>)</function></literal>
</entry>
<entry><type>void</type></entry>
<entry>Obtain exclusive advisory lock</entry>
<entry>Obtain exclusive session level advisory lock</entry>
</row>
<row>
<entry>
<literal><function>pg_advisory_lock_shared(<parameter>key</> <type>bigint</>)</function></literal>
</entry>
<entry><type>void</type></entry>
<entry>Obtain shared advisory lock</entry>
<entry>Obtain shared session level advisory lock</entry>
</row>
<row>
<entry>
<literal><function>pg_advisory_lock_shared(<parameter>key1</> <type>int</>, <parameter>key2</> <type>int</>)</function></literal>
</entry>
<entry><type>void</type></entry>
<entry>Obtain shared advisory lock</entry>
<entry>Obtain shared session level advisory lock</entry>
</row>
<row>
<entry>
<literal><function>pg_advisory_unlock(<parameter>key</> <type>bigint</>)</function></literal>
</entry>
<entry><type>boolean</type></entry>
<entry>Release an exclusive advisory lock</entry>
<entry>Release an exclusive session level advisory lock</entry>
</row>
<row>
<entry>
<literal><function>pg_advisory_unlock(<parameter>key1</> <type>int</>, <parameter>key2</> <type>int</>)</function></literal>
</entry>
<entry><type>boolean</type></entry>
<entry>Release an exclusive advisory lock</entry>
<entry>Release an exclusive session level advisory lock</entry>
</row>
<row>
<entry>
<literal><function>pg_advisory_unlock_all()</function></literal>
</entry>
<entry><type>void</type></entry>
<entry>Release all advisory locks held by the current session</entry>
<entry>Release all session level advisory locks held by the current session</entry>
</row>
<row>
<entry>
<literal><function>pg_advisory_unlock_shared(<parameter>key</> <type>bigint</>)</function></literal>
</entry>
<entry><type>boolean</type></entry>
<entry>Release a shared advisory lock</entry>
<entry>Release a shared session level advisory lock</entry>
</row>
<row>
<entry>
<literal><function>pg_advisory_unlock_shared(<parameter>key1</> <type>int</>, <parameter>key2</> <type>int</>)</function></literal>
</entry>
<entry><type>boolean</type></entry>
<entry>Release a shared advisory lock</entry>
<entry>Release a shared session level advisory lock</entry>
</row>
<row>
<entry>
<literal><function>pg_advisory_xact_lock(<parameter>key</> <type>bigint</>)</function></literal>
</entry>
<entry><type>void</type></entry>
<entry>Obtain exclusive transaction level advisory lock</entry>
</row>
<row>
<entry>
<literal><function>pg_advisory_xact_lock(<parameter>key1</> <type>int</>, <parameter>key2</> <type>int</>)</function></literal>
</entry>
<entry><type>void</type></entry>
<entry>Obtain exclusive transaction level advisory lock</entry>
</row>
<row>
<entry>
<literal><function>pg_advisory_xact_lock_shared(<parameter>key</> <type>bigint</>)</function></literal>
</entry>
<entry><type>void</type></entry>
<entry>Obtain shared transaction level advisory lock</entry>
</row>
<row>
<entry>
<literal><function>pg_advisory_xact_lock_shared(<parameter>key1</> <type>int</>, <parameter>key2</> <type>int</>)</function></literal>
</entry>
<entry><type>void</type></entry>
<entry>Obtain shared advisory lock for the current transaction</entry>
</row>
<row>
<entry>
<literal><function>pg_try_advisory_lock(<parameter>key</> <type>bigint</>)</function></literal>
</entry>
<entry><type>boolean</type></entry>
<entry>Obtain exclusive advisory lock if available</entry>
<entry>Obtain exclusive session level advisory lock if available</entry>
</row>
<row>
<entry>
<literal><function>pg_try_advisory_lock(<parameter>key1</> <type>int</>, <parameter>key2</> <type>int</>)</function></literal>
</entry>
<entry><type>boolean</type></entry>
<entry>Obtain exclusive advisory lock if available</entry>
<entry>Obtain exclusive session level advisory lock if available</entry>
</row>
<row>
<entry>
<literal><function>pg_try_advisory_lock_shared(<parameter>key</> <type>bigint</>)</function></literal>
</entry>
<entry><type>boolean</type></entry>
<entry>Obtain shared advisory lock if available</entry>
<entry>Obtain shared session level advisory lock if available</entry>
</row>
<row>
<entry>
<literal><function>pg_try_advisory_lock_shared(<parameter>key1</> <type>int</>, <parameter>key2</> <type>int</>)</function></literal>
</entry>
<entry><type>boolean</type></entry>
<entry>Obtain shared advisory lock if available</entry>
<entry>Obtain shared session level advisory lock if available</entry>
</row>
<row>
<entry>
<literal><function>pg_try_advisory_xact_lock(<parameter>key</> <type>bigint</>)</function></literal>
</entry>
<entry><type>boolean</type></entry>
<entry>Obtain exclusive transaction level advisory lock if available</entry>
</row>
<row>
<entry>
<literal><function>pg_try_advisory_xact_lock(<parameter>key1</> <type>int</>, <parameter>key2</> <type>int</>)</function></literal>
</entry>
<entry><type>boolean</type></entry>
<entry>Obtain exclusive transaction level advisory lock if available</entry>
</row>
<row>
<entry>
<literal><function>pg_try_advisory_xact_lock_shared(<parameter>key</> <type>bigint</>)</function></literal>
</entry>
<entry><type>boolean</type></entry>
<entry>Obtain shared transaction level advisory lock if available</entry>
</row>
<row>
<entry>
<literal><function>pg_try_advisory_xact_lock_shared(<parameter>key1</> <type>int</>, <parameter>key2</> <type>int</>)</function></literal>
</entry>
<entry><type>boolean</type></entry>
<entry>Obtain shared transaction level advisory lock if available</entry>
</row>
</tbody>
</tgroup>
@ -14758,12 +14814,50 @@ SELECT (pg_stat_file('filename')).modification;
a shared rather than an exclusive lock.
</para>
<indexterm>
<primary>pg_advisory_xact_lock</primary>
</indexterm>
<para>
<function>pg_advisory_xact_lock</> works the same as
<function>pg_advisory_lock</>, expect the lock is automatically released
at the end of the current transaction and can not be released explicitly.
</para>
<indexterm>
<primary>pg_advisory_xact_lock_shared</primary>
</indexterm>
<para>
<function>pg_advisory_xact_lock_shared</> works the same as
<function>pg_advisory_lock_shared</>, expect the lock is automatically released
at the end of the current transaction and can not be released explicitly.
</para>
<indexterm>
<primary>pg_try_advisory_xact_lock</primary>
</indexterm>
<para>
<function>pg_try_advisory_xact_lock</> works the same as
<function>pg_try_advisory_lock</>, expect the lock, if acquired,
is automatically released at the end of the current transaction and
can not be released explicitly.
</para>
<indexterm>
<primary>pg_try_advisory_xact_lock_shared</primary>
</indexterm>
<para>
<function>pg_try_advisory_xact_lock_shared</> works the same as
<function>pg_try_advisory_lock_shared</>, expect the lock, if acquired,
is automatically released at the end of the current transaction and
can not be released explicitly.
</para>
<indexterm>
<primary>pg_advisory_unlock</primary>
</indexterm>
<para>
<function>pg_advisory_unlock</> will release a previously-acquired
exclusive advisory lock. It
exclusive session level advisory lock. It
returns <literal>true</> if the lock is successfully released.
If the lock was not held, it will return <literal>false</>,
and in addition, an SQL warning will be raised by the server.
@ -14775,15 +14869,15 @@ SELECT (pg_stat_file('filename')).modification;
<para>
<function>pg_advisory_unlock_shared</> works the same as
<function>pg_advisory_unlock</>,
except it releases a shared advisory lock.
except it releases a shared session level advisory lock.
</para>
<indexterm>
<primary>pg_advisory_unlock_all</primary>
</indexterm>
<para>
<function>pg_advisory_unlock_all</> will release all advisory locks
held by the current session. (This function is implicitly invoked
<function>pg_advisory_unlock_all</> will release all session level advisory
locks held by the current session. (This function is implicitly invoked
at session end, even if the client disconnects ungracefully.)
</para>

35
doc/src/sgml/mvcc.sgml
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@ -1199,19 +1199,28 @@ UPDATE accounts SET balance = balance - 100.00 WHERE acctnum = 22222;
called <firstterm>advisory locks</>, because the system does not
enforce their use &mdash; it is up to the application to use them
correctly. Advisory locks can be useful for locking strategies
that are an awkward fit for the MVCC model. Once acquired, an
advisory lock is held until explicitly released or the session ends.
Unlike standard locks, advisory locks do not
honor transaction semantics: a lock acquired during a
transaction that is later rolled back will still be held following the
that are an awkward fit for the MVCC model.</para>
<para>
There are two different types of advisory locks in
<productname>PostgreSQL</productname>: session level and transaction level.
Once acquired, a session level advisory lock is held until explicitly
released or the session ends. Unlike standard locks, session level
advisory locks do not honor transaction semantics: a lock acquired during
a transaction that is later rolled back will still be held following the
rollback, and likewise an unlock is effective even if the calling
transaction fails later. The same lock can be acquired multiple times by
its owning process: for each lock request there must be a corresponding
unlock request before the lock is actually released. (If a session
already holds a given lock, additional requests will always succeed, even
if other sessions are awaiting the lock.) Like all locks in
<productname>PostgreSQL</productname>, a complete list of advisory
locks currently held by any session can be found in the
transaction fails later. The same session level lock can be acquired
multiple times by its owning process: for each lock request there must be
a corresponding unlock request before the lock is actually released. (If a
session already holds a given lock, additional requests will always succeed,
even if other sessions are awaiting the lock.) Transaction level locks on
the other hand behave more like regular locks; they are automatically
released at the end of the transaction, and can not be explicitly unlocked.
Session and transaction level locks share the same lock space, which means
that a transaction level lock will prevent another session from obtaining
a session level lock on that same resource and vice versa.
Like all locks in <productname>PostgreSQL</productname>, a complete list of
advisory locks currently held by any session can be found in the
<link linkend="view-pg-locks"><structname>pg_locks</structname></link>
system view.
</para>
@ -1233,7 +1242,7 @@ UPDATE accounts SET balance = balance - 100.00 WHERE acctnum = 22222;
strategies typical of so called <quote>flat file</> data management
systems.
While a flag stored in a table could be used for the same purpose,
advisory locks are faster, avoid MVCC bloat, and are automatically
advisory locks are faster, avoid MVCC bloat, and can be automatically
cleaned up by the server at the end of the session.
In certain cases using this advisory locking method, especially in queries
involving explicit ordering and <literal>LIMIT</> clauses, care must be

11
src/backend/storage/lmgr/README
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@ -505,7 +505,7 @@ User Locks
----------
User locks are handled totally on the application side as long term
cooperative locks which extend beyond the normal transaction boundaries.
cooperative locks which may extend beyond the normal transaction boundaries.
Their purpose is to indicate to an application that someone is `working'
on an item. So it is possible to put an user lock on a tuple's oid,
retrieve the tuple, work on it for an hour and then update it and remove
@ -516,9 +516,12 @@ level by someone.
User locks and normal locks are completely orthogonal and they don't
interfere with each other.
User locks are always held as session locks, so that they are not released at
transaction end. They must be released explicitly by the application --- but
they are released automatically when a backend terminates.
There are two types of user locks: session level and transaction level.
Session level user locks are not released at transaction end. They must
be released explicitly by the application --- but they are released
automatically when a backend terminates. On the other hand, transaction
level user locks are released automatically at the end of the transaction
as like as other normal locks.
Locking during Hot Standby
--------------------------

101
src/backend/storage/lmgr/lock.c
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@ -130,7 +130,7 @@ static const LockMethodData default_lockmethod = {
static const LockMethodData user_lockmethod = {
AccessExclusiveLock, /* highest valid lock mode number */
false,
true,
LockConflicts,
lock_mode_names,
#ifdef LOCK_DEBUG
@ -256,6 +256,7 @@ static uint32 proclock_hash(const void *key, Size keysize);
static void RemoveLocalLock(LOCALLOCK *locallock);
static void GrantLockLocal(LOCALLOCK *locallock, ResourceOwner owner);
static void WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner);
static void ReleaseLockForOwner(LOCALLOCK *locallock, ResourceOwner owner);
static bool UnGrantLock(LOCK *lock, LOCKMODE lockmode,
PROCLOCK *proclock, LockMethod lockMethodTable);
static void CleanUpLock(LOCK *lock, PROCLOCK *proclock,
@ -1483,6 +1484,31 @@ LockRelease(const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock)
return TRUE;
}
/*
* LockReleaseSession -- Release all session locks of the specified lock method
* that are held by the current process.
*/
void
LockReleaseSession(LOCKMETHODID lockmethodid)
{
HASH_SEQ_STATUS status;
LOCALLOCK *locallock;
if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
elog(ERROR, "unrecognized lock method: %d", lockmethodid);
hash_seq_init(&status, LockMethodLocalHash);
while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
{
/* Ignore items that are not of the specified lock method */
if (LOCALLOCK_LOCKMETHOD(*locallock) != lockmethodid)
continue;
ReleaseLockForOwner(locallock, NULL);
}
}
/*
* LockReleaseAll -- Release all locks of the specified lock method that
* are held by the current process.
@ -1679,8 +1705,6 @@ LockReleaseCurrentOwner(void)
{
HASH_SEQ_STATUS status;
LOCALLOCK *locallock;
LOCALLOCKOWNER *lockOwners;
int i;
hash_seq_init(&status, LockMethodLocalHash);
@ -1690,38 +1714,51 @@ LockReleaseCurrentOwner(void)
if (!LockMethods[LOCALLOCK_LOCKMETHOD(*locallock)]->transactional)
continue;
/* Scan to see if there are any locks belonging to current owner */
lockOwners = locallock->lockOwners;
for (i = locallock->numLockOwners - 1; i >= 0; i--)
ReleaseLockForOwner(locallock, CurrentResourceOwner);
}
}
/*
* Subroutine to release a lock belonging to the 'owner' if found.
* 'owner' can be NULL to release a session lock.
*/
static void
ReleaseLockForOwner(LOCALLOCK *locallock, ResourceOwner owner)
{
int i;
LOCALLOCKOWNER *lockOwners;
/* Scan to see if there are any locks belonging to the owner */
lockOwners = locallock->lockOwners;
for (i = locallock->numLockOwners - 1; i >= 0; i--)
{
if (lockOwners[i].owner == owner)
{
if (lockOwners[i].owner == CurrentResourceOwner)
Assert(lockOwners[i].nLocks > 0);
if (lockOwners[i].nLocks < locallock->nLocks)
{
Assert(lockOwners[i].nLocks > 0);
if (lockOwners[i].nLocks < locallock->nLocks)
{
/*
* We will still hold this lock after forgetting this
* ResourceOwner.
*/
locallock->nLocks -= lockOwners[i].nLocks;
/* compact out unused slot */
locallock->numLockOwners--;
if (i < locallock->numLockOwners)
lockOwners[i] = lockOwners[locallock->numLockOwners];
}
else
{
Assert(lockOwners[i].nLocks == locallock->nLocks);
/* We want to call LockRelease just once */
lockOwners[i].nLocks = 1;
locallock->nLocks = 1;
if (!LockRelease(&locallock->tag.lock,
locallock->tag.mode,
false))
elog(WARNING, "LockReleaseCurrentOwner: failed??");
}
break;
/*
* We will still hold this lock after forgetting this
* ResourceOwner.
*/
locallock->nLocks -= lockOwners[i].nLocks;
/* compact out unused slot */
locallock->numLockOwners--;
if (i < locallock->numLockOwners)
lockOwners[i] = lockOwners[locallock->numLockOwners];
}
else
{
Assert(lockOwners[i].nLocks == locallock->nLocks);
/* We want to call LockRelease just once */
lockOwners[i].nLocks = 1;
locallock->nLocks = 1;
if (!LockRelease(&locallock->tag.lock,
locallock->tag.mode,
owner == NULL))
elog(WARNING, "ReleaseLockForOwner: failed??");
}
break;
}
}
}

5
src/backend/storage/lmgr/proc.c
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@ -629,8 +629,6 @@ LockWaitCancel(void)
* At subtransaction abort, we release all locks held by the subtransaction;
* this is implemented by retail releasing of the locks under control of
* the ResourceOwner mechanism.
*
* Note that user locks are not released in any case.
*/
void
ProcReleaseLocks(bool isCommit)
@ -641,6 +639,9 @@ ProcReleaseLocks(bool isCommit)
LockWaitCancel();
/* Release locks */
LockReleaseAll(DEFAULT_LOCKMETHOD, !isCommit);
/* Release transaction level advisory locks */
LockReleaseAll(USER_LOCKMETHOD, false);
}

154
src/backend/utils/adt/lockfuncs.c
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@ -421,6 +421,23 @@ pg_advisory_lock_int8(PG_FUNCTION_ARGS)
PG_RETURN_VOID();
}
/*
* pg_advisory_xact_lock(int8) - acquire xact scoped
* exclusive lock on an int8 key
*/
Datum
pg_advisory_xact_lock_int8(PG_FUNCTION_ARGS)
{
int64 key = PG_GETARG_INT64(0);
LOCKTAG tag;
SET_LOCKTAG_INT64(tag, key);
(void) LockAcquire(&tag, ExclusiveLock, false, false);
PG_RETURN_VOID();
}
/*
* pg_advisory_lock_shared(int8) - acquire share lock on an int8 key
*/
@ -437,6 +454,23 @@ pg_advisory_lock_shared_int8(PG_FUNCTION_ARGS)
PG_RETURN_VOID();
}
/*
* pg_advisory_xact_lock_shared(int8) - acquire xact scoped
* share lock on an int8 key
*/
Datum
pg_advisory_xact_lock_shared_int8(PG_FUNCTION_ARGS)
{
int64 key = PG_GETARG_INT64(0);
LOCKTAG tag;
SET_LOCKTAG_INT64(tag, key);
(void) LockAcquire(&tag, ShareLock, false, false);
PG_RETURN_VOID();
}
/*
* pg_try_advisory_lock(int8) - acquire exclusive lock on an int8 key, no wait
*
@ -456,6 +490,26 @@ pg_try_advisory_lock_int8(PG_FUNCTION_ARGS)
PG_RETURN_BOOL(res != LOCKACQUIRE_NOT_AVAIL);
}
/*
* pg_try_advisory_xact_lock(int8) - acquire xact scoped
* exclusive lock on an int8 key, no wait
*
* Returns true if successful, false if lock not available
*/
Datum
pg_try_advisory_xact_lock_int8(PG_FUNCTION_ARGS)
{
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);
}
/*
* pg_try_advisory_lock_shared(int8) - acquire share lock on an int8 key, no wait
*
@ -475,6 +529,26 @@ pg_try_advisory_lock_shared_int8(PG_FUNCTION_ARGS)
PG_RETURN_BOOL(res != LOCKACQUIRE_NOT_AVAIL);
}
/*
* pg_try_advisory_xact_lock_shared(int8) - acquire xact scoped
* share lock on an int8 key, no wait
*
* Returns true if successful, false if lock not available
*/
Datum
pg_try_advisory_xact_lock_shared_int8(PG_FUNCTION_ARGS)
{
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);
}
/*
* pg_advisory_unlock(int8) - release exclusive lock on an int8 key
*
@ -530,6 +604,24 @@ pg_advisory_lock_int4(PG_FUNCTION_ARGS)
PG_RETURN_VOID();
}
/*
* pg_advisory_xact_lock(int4, int4) - acquire xact scoped
* exclusive lock on 2 int4 keys
*/
Datum
pg_advisory_xact_lock_int4(PG_FUNCTION_ARGS)
{
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();
}
/*
* pg_advisory_lock_shared(int4, int4) - acquire share lock on 2 int4 keys
*/
@ -547,6 +639,24 @@ pg_advisory_lock_shared_int4(PG_FUNCTION_ARGS)
PG_RETURN_VOID();
}
/*
* pg_advisory_xact_lock_shared(int4, int4) - acquire xact scoped
* share lock on 2 int4 keys
*/
Datum
pg_advisory_xact_lock_shared_int4(PG_FUNCTION_ARGS)
{
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();
}
/*
* pg_try_advisory_lock(int4, int4) - acquire exclusive lock on 2 int4 keys, no wait
*
@ -567,6 +677,27 @@ pg_try_advisory_lock_int4(PG_FUNCTION_ARGS)
PG_RETURN_BOOL(res != LOCKACQUIRE_NOT_AVAIL);
}
/*
* pg_try_advisory_xact_lock(int4, int4) - acquire xact scoped
* exclusive lock on 2 int4 keys, no wait
*
* Returns true if successful, false if lock not available
*/
Datum
pg_try_advisory_xact_lock_int4(PG_FUNCTION_ARGS)
{
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);
}
/*
* pg_try_advisory_lock_shared(int4, int4) - acquire share lock on 2 int4 keys, no wait
*
@ -587,6 +718,27 @@ pg_try_advisory_lock_shared_int4(PG_FUNCTION_ARGS)
PG_RETURN_BOOL(res != LOCKACQUIRE_NOT_AVAIL);
}
/*
* pg_try_advisory_xact_lock_shared(int4, int4) - acquire xact scoped
* share lock on 2 int4 keys, no wait
*
* Returns true if successful, false if lock not available
*/
Datum
pg_try_advisory_xact_lock_shared_int4(PG_FUNCTION_ARGS)
{
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);
}
/*
* pg_advisory_unlock(int4, int4) - release exclusive lock on 2 int4 keys
*
@ -633,7 +785,7 @@ pg_advisory_unlock_shared_int4(PG_FUNCTION_ARGS)
Datum
pg_advisory_unlock_all(PG_FUNCTION_ARGS)
{
LockReleaseAll(USER_LOCKMETHOD, true);
LockReleaseSession(USER_LOCKMETHOD);
PG_RETURN_VOID();
}

2
src/include/catalog/catversion.h
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@ -53,6 +53,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 201102171
#define CATALOG_VERSION_NO 201102181
#endif

16
src/include/catalog/pg_proc.h
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@ -4420,25 +4420,41 @@ DESCR("is contained by");
/* userlock replacements */
DATA(insert OID = 2880 ( pg_advisory_lock PGNSP PGUID 12 1 0 0 f f f t f v 1 0 2278 "20" _null_ _null_ _null_ _null_ pg_advisory_lock_int8 _null_ _null_ _null_ ));
DESCR("obtain exclusive a4dvisory lock");
DATA(insert OID = 3089 ( pg_advisory_xact_lock PGNSP PGUID 12 1 0 0 f f f t f v 1 0 2278 "20" _null_ _null_ _null_ _null_ pg_advisory_xact_lock_int8 _null_ _null_ _null_ ));
DESCR("obtain exclusive advisory lock");
DATA(insert OID = 2881 ( pg_advisory_lock_shared PGNSP PGUID 12 1 0 0 f f f t f v 1 0 2278 "20" _null_ _null_ _null_ _null_ pg_advisory_lock_shared_int8 _null_ _null_ _null_ ));
DESCR("obtain shared advisory lock");
DATA(insert OID = 3090 ( pg_advisory_xact_lock_shared PGNSP PGUID 12 1 0 0 f f f t f v 1 0 2278 "20" _null_ _null_ _null_ _null_ pg_advisory_xact_lock_shared_int8 _null_ _null_ _null_ ));
DESCR("obtain shared advisory lock");
DATA(insert OID = 2882 ( pg_try_advisory_lock PGNSP PGUID 12 1 0 0 f f f t f v 1 0 16 "20" _null_ _null_ _null_ _null_ pg_try_advisory_lock_int8 _null_ _null_ _null_ ));
DESCR("obtain exclusive advisory lock if available");
DATA(insert OID = 3091 ( pg_try_advisory_xact_lock PGNSP PGUID 12 1 0 0 f f f t f v 1 0 16 "20" _null_ _null_ _null_ _null_ pg_try_advisory_xact_lock_int8 _null_ _null_ _null_ ));
DESCR("obtain exclusive advisory lock if available");
DATA(insert OID = 2883 ( pg_try_advisory_lock_shared PGNSP PGUID 12 1 0 0 f f f t f v 1 0 16 "20" _null_ _null_ _null_ _null_ pg_try_advisory_lock_shared_int8 _null_ _null_ _null_ ));
DESCR("obtain shared advisory lock if available");
DATA(insert OID = 3092 ( pg_try_advisory_xact_lock_shared PGNSP PGUID 12 1 0 0 f f f t f v 1 0 16 "20" _null_ _null_ _null_ _null_ pg_try_advisory_xact_lock_shared_int8 _null_ _null_ _null_ ));
DESCR("obtain shared advisory lock if available");
DATA(insert OID = 2884 ( pg_advisory_unlock PGNSP PGUID 12 1 0 0 f f f t f v 1 0 16 "20" _null_ _null_ _null_ _null_ pg_advisory_unlock_int8 _null_ _null_ _null_ ));
DESCR("release exclusive advisory lock");
DATA(insert OID = 2885 ( pg_advisory_unlock_shared PGNSP PGUID 12 1 0 0 f f f t f v 1 0 16 "20" _null_ _null_ _null_ _null_ pg_advisory_unlock_shared_int8 _null_ _null_ _null_ ));
DESCR("release shared advisory lock");
DATA(insert OID = 2886 ( pg_advisory_lock PGNSP PGUID 12 1 0 0 f f f t f v 2 0 2278 "23 23" _null_ _null_ _null_ _null_ pg_advisory_lock_int4 _null_ _null_ _null_ ));
DESCR("obtain exclusive advisory lock");
DATA(insert OID = 3093 ( pg_advisory_xact_lock PGNSP PGUID 12 1 0 0 f f f t f v 2 0 2278 "23 23" _null_ _null_ _null_ _null_ pg_advisory_xact_lock_int4 _null_ _null_ _null_ ));
DESCR("obtain exclusive advisory lock");
DATA(insert OID = 2887 ( pg_advisory_lock_shared PGNSP PGUID 12 1 0 0 f f f t f v 2 0 2278 "23 23" _null_ _null_ _null_ _null_ pg_advisory_lock_shared_int4 _null_ _null_ _null_ ));
DESCR("obtain shared advisory lock");
DATA(insert OID = 3094 ( pg_advisory_xact_lock_shared PGNSP PGUID 12 1 0 0 f f f t f v 2 0 2278 "23 23" _null_ _null_ _null_ _null_ pg_advisory_xact_lock_shared_int4 _null_ _null_ _null_ ));
DESCR("obtain shared advisory lock");
DATA(insert OID = 2888 ( pg_try_advisory_lock PGNSP PGUID 12 1 0 0 f f f t f v 2 0 16 "23 23" _null_ _null_ _null_ _null_ pg_try_advisory_lock_int4 _null_ _null_ _null_ ));
DESCR("obtain exclusive advisory lock if available");
DATA(insert OID = 3095 ( pg_try_advisory_xact_lock PGNSP PGUID 12 1 0 0 f f f t f v 2 0 16 "23 23" _null_ _null_ _null_ _null_ pg_try_advisory_xact_lock_int4 _null_ _null_ _null_ ));
DESCR("obtain exclusive advisory lock if available");
DATA(insert OID = 2889 ( pg_try_advisory_lock_shared PGNSP PGUID 12 1 0 0 f f f t f v 2 0 16 "23 23" _null_ _null_ _null_ _null_ pg_try_advisory_lock_shared_int4 _null_ _null_ _null_ ));
DESCR("obtain shared advisory lock if available");
DATA(insert OID = 3096 ( pg_try_advisory_xact_lock_shared PGNSP PGUID 12 1 0 0 f f f t f v 2 0 16 "23 23" _null_ _null_ _null_ _null_ pg_try_advisory_xact_lock_shared_int4 _null_ _null_ _null_ ));
DESCR("obtain shared advisory lock if available");
DATA(insert OID = 2890 ( pg_advisory_unlock PGNSP PGUID 12 1 0 0 f f f t f v 2 0 16 "23 23" _null_ _null_ _null_ _null_ pg_advisory_unlock_int4 _null_ _null_ _null_ ));
DESCR("release exclusive advisory lock");
DATA(insert OID = 2891 ( pg_advisory_unlock_shared PGNSP PGUID 12 1 0 0 f f f t f v 2 0 16 "23 23" _null_ _null_ _null_ _null_ pg_advisory_unlock_shared_int4 _null_ _null_ _null_ ));

1
src/include/storage/lock.h
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@ -484,6 +484,7 @@ extern LockAcquireResult LockAcquireExtended(const LOCKTAG *locktag,
bool report_memory_error);
extern bool LockRelease(const LOCKTAG *locktag,
LOCKMODE lockmode, bool sessionLock);
extern void LockReleaseSession(LOCKMETHODID lockmethodid);
extern void LockReleaseAll(LOCKMETHODID lockmethodid, bool allLocks);
extern void LockReleaseCurrentOwner(void);
extern void LockReassignCurrentOwner(void);

8
src/include/utils/builtins.h
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@ -995,15 +995,23 @@ extern Datum show_all_settings(PG_FUNCTION_ARGS);
/* lockfuncs.c */
extern Datum pg_lock_status(PG_FUNCTION_ARGS);
extern Datum pg_advisory_lock_int8(PG_FUNCTION_ARGS);
extern Datum pg_advisory_xact_lock_int8(PG_FUNCTION_ARGS);
extern Datum pg_advisory_lock_shared_int8(PG_FUNCTION_ARGS);
extern Datum pg_advisory_xact_lock_shared_int8(PG_FUNCTION_ARGS);
extern Datum pg_try_advisory_lock_int8(PG_FUNCTION_ARGS);
extern Datum pg_try_advisory_xact_lock_int8(PG_FUNCTION_ARGS);
extern Datum pg_try_advisory_lock_shared_int8(PG_FUNCTION_ARGS);
extern Datum pg_try_advisory_xact_lock_shared_int8(PG_FUNCTION_ARGS);
extern Datum pg_advisory_unlock_int8(PG_FUNCTION_ARGS);
extern Datum pg_advisory_unlock_shared_int8(PG_FUNCTION_ARGS);
extern Datum pg_advisory_lock_int4(PG_FUNCTION_ARGS);
extern Datum pg_advisory_xact_lock_int4(PG_FUNCTION_ARGS);
extern Datum pg_advisory_lock_shared_int4(PG_FUNCTION_ARGS);
extern Datum pg_advisory_xact_lock_shared_int4(PG_FUNCTION_ARGS);
extern Datum pg_try_advisory_lock_int4(PG_FUNCTION_ARGS);
extern Datum pg_try_advisory_xact_lock_int4(PG_FUNCTION_ARGS);
extern Datum pg_try_advisory_lock_shared_int4(PG_FUNCTION_ARGS);
extern Datum pg_try_advisory_xact_lock_shared_int4(PG_FUNCTION_ARGS);
extern Datum pg_advisory_unlock_int4(PG_FUNCTION_ARGS);
extern Datum pg_advisory_unlock_shared_int4(PG_FUNCTION_ARGS);
extern Datum pg_advisory_unlock_all(PG_FUNCTION_ARGS);

275
src/test/regress/expected/advisory_lock.out
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@ -0,0 +1,275 @@
--
-- ADVISORY LOCKS
--
BEGIN;
SELECT
pg_advisory_xact_lock(1), pg_advisory_xact_lock_shared(2),
pg_advisory_xact_lock(1, 1), pg_advisory_xact_lock_shared(2, 2);
pg_advisory_xact_lock | pg_advisory_xact_lock_shared | pg_advisory_xact_lock | pg_advisory_xact_lock_shared
-----------------------+------------------------------+-----------------------+------------------------------
| | |
(1 row)
SELECT locktype, classid, objid, objsubid, mode, granted
FROM pg_locks WHERE locktype = 'advisory'
ORDER BY classid, objid, objsubid;
locktype | classid | objid | objsubid | mode | granted
----------+---------+-------+----------+---------------+---------
advisory | 0 | 1 | 1 | ExclusiveLock | t
advisory | 0 | 2 | 1 | ShareLock | t
advisory | 1 | 1 | 2 | ExclusiveLock | t
advisory | 2 | 2 | 2 | ShareLock | t
(4 rows)
-- pg_advisory_unlock_all() shouldn't release xact locks
SELECT pg_advisory_unlock_all();
pg_advisory_unlock_all
------------------------
(1 row)
SELECT count(*) FROM pg_locks WHERE locktype = 'advisory';
count
-------
4
(1 row)
-- can't unlock xact locks
SELECT
pg_advisory_unlock(1), pg_advisory_unlock_shared(2),
pg_advisory_unlock(1, 1), pg_advisory_unlock_shared(2, 2);
WARNING: you don't own a lock of type ExclusiveLock
WARNING: you don't own a lock of type ShareLock
WARNING: you don't own a lock of type ExclusiveLock
WARNING: you don't own a lock of type ShareLock
pg_advisory_unlock | pg_advisory_unlock_shared | pg_advisory_unlock | pg_advisory_unlock_shared
--------------------+---------------------------+--------------------+---------------------------
f | f | f | f
(1 row)
-- automatically release xact locks at commit
COMMIT;
SELECT count(*) FROM pg_locks WHERE locktype = 'advisory';
count
-------
0
(1 row)
BEGIN;
-- holding both session and xact locks on the same objects, xact first
SELECT
pg_advisory_xact_lock(1), pg_advisory_xact_lock_shared(2),
pg_advisory_xact_lock(1, 1), pg_advisory_xact_lock_shared(2, 2);
pg_advisory_xact_lock | pg_advisory_xact_lock_shared | pg_advisory_xact_lock | pg_advisory_xact_lock_shared
-----------------------+------------------------------+-----------------------+------------------------------
| | |
(1 row)
SELECT locktype, classid, objid, objsubid, mode, granted
FROM pg_locks WHERE locktype = 'advisory'
ORDER BY classid, objid, objsubid;
locktype | classid | objid | objsubid | mode | granted
----------+---------+-------+----------+---------------+---------
advisory | 0 | 1 | 1 | ExclusiveLock | t
advisory | 0 | 2 | 1 | ShareLock | t
advisory | 1 | 1 | 2 | ExclusiveLock | t
advisory | 2 | 2 | 2 | ShareLock | t
(4 rows)
SELECT
pg_advisory_lock(1), pg_advisory_lock_shared(2),
pg_advisory_lock(1, 1), pg_advisory_lock_shared(2, 2);
pg_advisory_lock | pg_advisory_lock_shared | pg_advisory_lock | pg_advisory_lock_shared
------------------+-------------------------+------------------+-------------------------
| | |
(1 row)
ROLLBACK;
SELECT locktype, classid, objid, objsubid, mode, granted
FROM pg_locks WHERE locktype = 'advisory'
ORDER BY classid, objid, objsubid;
locktype | classid | objid | objsubid | mode | granted
----------+---------+-------+----------+---------------+---------
advisory | 0 | 1 | 1 | ExclusiveLock | t
advisory | 0 | 2 | 1 | ShareLock | t
advisory | 1 | 1 | 2 | ExclusiveLock | t
advisory | 2 | 2 | 2 | ShareLock | t
(4 rows)
-- unlocking session locks
SELECT
pg_advisory_unlock(1), pg_advisory_unlock(1),
pg_advisory_unlock_shared(2), pg_advisory_unlock_shared(2),
pg_advisory_unlock(1, 1), pg_advisory_unlock(1, 1),
pg_advisory_unlock_shared(2, 2), pg_advisory_unlock_shared(2, 2);
WARNING: you don't own a lock of type ExclusiveLock
WARNING: you don't own a lock of type ShareLock
WARNING: you don't own a lock of type ExclusiveLock
WARNING: you don't own a lock of type ShareLock
pg_advisory_unlock | pg_advisory_unlock | pg_advisory_unlock_shared | pg_advisory_unlock_shared | pg_advisory_unlock | pg_advisory_unlock | pg_advisory_unlock_shared | pg_advisory_unlock_shared
--------------------+--------------------+---------------------------+---------------------------+--------------------+--------------------+---------------------------+---------------------------
t | f | t | f | t | f | t | f
(1 row)
SELECT count(*) FROM pg_locks WHERE locktype = 'advisory';
count
-------
0
(1 row)
BEGIN;
-- holding both session and xact locks on the same objects, session first
SELECT
pg_advisory_lock(1), pg_advisory_lock_shared(2),
pg_advisory_lock(1, 1), pg_advisory_lock_shared(2, 2);
pg_advisory_lock | pg_advisory_lock_shared | pg_advisory_lock | pg_advisory_lock_shared
------------------+-------------------------+------------------+-------------------------
| | |
(1 row)
SELECT locktype, classid, objid, objsubid, mode, granted
FROM pg_locks WHERE locktype = 'advisory'
ORDER BY classid, objid, objsubid;
locktype | classid | objid | objsubid | mode | granted
----------+---------+-------+----------+---------------+---------
advisory | 0 | 1 | 1 | ExclusiveLock | t
advisory | 0 | 2 | 1 | ShareLock | t
advisory | 1 | 1 | 2 | ExclusiveLock | t
advisory | 2 | 2 | 2 | ShareLock | t
(4 rows)
SELECT
pg_advisory_xact_lock(1), pg_advisory_xact_lock_shared(2),
pg_advisory_xact_lock(1, 1), pg_advisory_xact_lock_shared(2, 2);
pg_advisory_xact_lock | pg_advisory_xact_lock_shared | pg_advisory_xact_lock | pg_advisory_xact_lock_shared
-----------------------+------------------------------+-----------------------+------------------------------
| | |
(1 row)
ROLLBACK;
SELECT locktype, classid, objid, objsubid, mode, granted
FROM pg_locks WHERE locktype = 'advisory'
ORDER BY classid, objid, objsubid;
locktype | classid | objid | objsubid | mode | granted
----------+---------+-------+----------+---------------+---------
advisory | 0 | 1 | 1 | ExclusiveLock | t
advisory | 0 | 2 | 1 | ShareLock | t
advisory | 1 | 1 | 2 | ExclusiveLock | t
advisory | 2 | 2 | 2 | ShareLock | t
(4 rows)
-- releasing all session locks
SELECT pg_advisory_unlock_all();
pg_advisory_unlock_all
------------------------
(1 row)
SELECT count(*) FROM pg_locks WHERE locktype = 'advisory';
count
-------
0
(1 row)
BEGIN;
-- grabbing txn locks multiple times
SELECT
pg_advisory_xact_lock(1), pg_advisory_xact_lock(1),
pg_advisory_xact_lock_shared(2), pg_advisory_xact_lock_shared(2),
pg_advisory_xact_lock(1, 1), pg_advisory_xact_lock(1, 1),
pg_advisory_xact_lock_shared(2, 2), pg_advisory_xact_lock_shared(2, 2);
pg_advisory_xact_lock | pg_advisory_xact_lock | pg_advisory_xact_lock_shared | pg_advisory_xact_lock_shared | pg_advisory_xact_lock | pg_advisory_xact_lock | pg_advisory_xact_lock_shared | pg_advisory_xact_lock_shared
-----------------------+-----------------------+------------------------------+------------------------------+-----------------------+-----------------------+------------------------------+------------------------------
| | | | | | |
(1 row)
SELECT locktype, classid, objid, objsubid, mode, granted
FROM pg_locks WHERE locktype = 'advisory'
ORDER BY classid, objid, objsubid;
locktype | classid | objid | objsubid | mode | granted
----------+---------+-------+----------+---------------+---------
advisory | 0 | 1 | 1 | ExclusiveLock | t
advisory | 0 | 2 | 1 | ShareLock | t
advisory | 1 | 1 | 2 | ExclusiveLock | t
advisory | 2 | 2 | 2 | ShareLock | t
(4 rows)
COMMIT;
SELECT count(*) FROM pg_locks WHERE locktype = 'advisory';
count
-------
0
(1 row)
-- grabbing session locks multiple times
SELECT
pg_advisory_lock(1), pg_advisory_lock(1),
pg_advisory_lock_shared(2), pg_advisory_lock_shared(2),
pg_advisory_lock(1, 1), pg_advisory_lock(1, 1),
pg_advisory_lock_shared(2, 2), pg_advisory_lock_shared(2, 2);
pg_advisory_lock | pg_advisory_lock | pg_advisory_lock_shared | pg_advisory_lock_shared | pg_advisory_lock | pg_advisory_lock | pg_advisory_lock_shared | pg_advisory_lock_shared
------------------+------------------+-------------------------+-------------------------+------------------+------------------+-------------------------+-------------------------
| | | | | | |
(1 row)
SELECT locktype, classid, objid, objsubid, mode, granted
FROM pg_locks WHERE locktype = 'advisory'
ORDER BY classid, objid, objsubid;
locktype | classid | objid | objsubid | mode | granted
----------+---------+-------+----------+---------------+---------
advisory | 0 | 1 | 1 | ExclusiveLock | t
advisory | 0 | 2 | 1 | ShareLock | t
advisory | 1 | 1 | 2 | ExclusiveLock | t
advisory | 2 | 2 | 2 | ShareLock | t
(4 rows)
SELECT
pg_advisory_unlock(1), pg_advisory_unlock(1),
pg_advisory_unlock_shared(2), pg_advisory_unlock_shared(2),
pg_advisory_unlock(1, 1), pg_advisory_unlock(1, 1),
pg_advisory_unlock_shared(2, 2), pg_advisory_unlock_shared(2, 2);
pg_advisory_unlock | pg_advisory_unlock | pg_advisory_unlock_shared | pg_advisory_unlock_shared | pg_advisory_unlock | pg_advisory_unlock | pg_advisory_unlock_shared | pg_advisory_unlock_shared
--------------------+--------------------+---------------------------+---------------------------+--------------------+--------------------+---------------------------+---------------------------
t | t | t | t | t | t | t | t
(1 row)
SELECT count(*) FROM pg_locks WHERE locktype = 'advisory';
count
-------
0
(1 row)
-- .. and releasing them all at once
SELECT
pg_advisory_lock(1), pg_advisory_lock(1),
pg_advisory_lock_shared(2), pg_advisory_lock_shared(2),
pg_advisory_lock(1, 1), pg_advisory_lock(1, 1),
pg_advisory_lock_shared(2, 2), pg_advisory_lock_shared(2, 2);
pg_advisory_lock | pg_advisory_lock | pg_advisory_lock_shared | pg_advisory_lock_shared | pg_advisory_lock | pg_advisory_lock | pg_advisory_lock_shared | pg_advisory_lock_shared
------------------+------------------+-------------------------+-------------------------+------------------+------------------+-------------------------+-------------------------
| | | | | | |
(1 row)
SELECT locktype, classid, objid, objsubid, mode, granted
FROM pg_locks WHERE locktype = 'advisory'
ORDER BY classid, objid, objsubid;
locktype | classid | objid | objsubid | mode | granted
----------+---------+-------+----------+---------------+---------
advisory | 0 | 1 | 1 | ExclusiveLock | t
advisory | 0 | 2 | 1 | ShareLock | t
advisory | 1 | 1 | 2 | ExclusiveLock | t
advisory | 2 | 2 | 2 | ShareLock | t
(4 rows)
SELECT pg_advisory_unlock_all();
pg_advisory_unlock_all
------------------------
(1 row)
SELECT count(*) FROM pg_locks WHERE locktype = 'advisory';
count
-------
0
(1 row)

2
src/test/regress/parallel_schedule
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@ -84,7 +84,7 @@ test: rules
# ----------
# Another group of parallel tests
# ----------
test: select_views portals_p2 foreign_key cluster dependency guc bitmapops combocid tsearch tsdicts foreign_data window xmlmap functional_deps
test: select_views portals_p2 foreign_key cluster dependency guc bitmapops combocid tsearch tsdicts foreign_data window xmlmap functional_deps advisory_lock
# ----------
# Another group of parallel tests

1
src/test/regress/serial_schedule
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@ -105,6 +105,7 @@ test: foreign_data
test: window
test: xmlmap
test: functional_deps
test: advisory_lock
test: plancache
test: limit
test: plpgsql

146
src/test/regress/sql/advisory_lock.sql
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@ -0,0 +1,146 @@
--
-- ADVISORY LOCKS
--
BEGIN;
SELECT
pg_advisory_xact_lock(1), pg_advisory_xact_lock_shared(2),
pg_advisory_xact_lock(1, 1), pg_advisory_xact_lock_shared(2, 2);
SELECT locktype, classid, objid, objsubid, mode, granted
FROM pg_locks WHERE locktype = 'advisory'
ORDER BY classid, objid, objsubid;
-- pg_advisory_unlock_all() shouldn't release xact locks
SELECT pg_advisory_unlock_all();
SELECT count(*) FROM pg_locks WHERE locktype = 'advisory';
-- can't unlock xact locks
SELECT
pg_advisory_unlock(1), pg_advisory_unlock_shared(2),
pg_advisory_unlock(1, 1), pg_advisory_unlock_shared(2, 2);
-- automatically release xact locks at commit
COMMIT;
SELECT count(*) FROM pg_locks WHERE locktype = 'advisory';
BEGIN;
-- holding both session and xact locks on the same objects, xact first
SELECT
pg_advisory_xact_lock(1), pg_advisory_xact_lock_shared(2),
pg_advisory_xact_lock(1, 1), pg_advisory_xact_lock_shared(2, 2);
SELECT locktype, classid, objid, objsubid, mode, granted
FROM pg_locks WHERE locktype = 'advisory'
ORDER BY classid, objid, objsubid;
SELECT
pg_advisory_lock(1), pg_advisory_lock_shared(2),
pg_advisory_lock(1, 1), pg_advisory_lock_shared(2, 2);
ROLLBACK;
SELECT locktype, classid, objid, objsubid, mode, granted
FROM pg_locks WHERE locktype = 'advisory'
ORDER BY classid, objid, objsubid;
-- unlocking session locks
SELECT
pg_advisory_unlock(1), pg_advisory_unlock(1),
pg_advisory_unlock_shared(2), pg_advisory_unlock_shared(2),
pg_advisory_unlock(1, 1), pg_advisory_unlock(1, 1),
pg_advisory_unlock_shared(2, 2), pg_advisory_unlock_shared(2, 2);
SELECT count(*) FROM pg_locks WHERE locktype = 'advisory';
BEGIN;
-- holding both session and xact locks on the same objects, session first
SELECT
pg_advisory_lock(1), pg_advisory_lock_shared(2),
pg_advisory_lock(1, 1), pg_advisory_lock_shared(2, 2);
SELECT locktype, classid, objid, objsubid, mode, granted
FROM pg_locks WHERE locktype = 'advisory'
ORDER BY classid, objid, objsubid;
SELECT
pg_advisory_xact_lock(1), pg_advisory_xact_lock_shared(2),
pg_advisory_xact_lock(1, 1), pg_advisory_xact_lock_shared(2, 2);
ROLLBACK;
SELECT locktype, classid, objid, objsubid, mode, granted
FROM pg_locks WHERE locktype = 'advisory'
ORDER BY classid, objid, objsubid;
-- releasing all session locks
SELECT pg_advisory_unlock_all();
SELECT count(*) FROM pg_locks WHERE locktype = 'advisory';
BEGIN;
-- grabbing txn locks multiple times
SELECT
pg_advisory_xact_lock(1), pg_advisory_xact_lock(1),
pg_advisory_xact_lock_shared(2), pg_advisory_xact_lock_shared(2),
pg_advisory_xact_lock(1, 1), pg_advisory_xact_lock(1, 1),
pg_advisory_xact_lock_shared(2, 2), pg_advisory_xact_lock_shared(2, 2);
SELECT locktype, classid, objid, objsubid, mode, granted
FROM pg_locks WHERE locktype = 'advisory'
ORDER BY classid, objid, objsubid;
COMMIT;
SELECT count(*) FROM pg_locks WHERE locktype = 'advisory';
-- grabbing session locks multiple times
SELECT
pg_advisory_lock(1), pg_advisory_lock(1),
pg_advisory_lock_shared(2), pg_advisory_lock_shared(2),
pg_advisory_lock(1, 1), pg_advisory_lock(1, 1),
pg_advisory_lock_shared(2, 2), pg_advisory_lock_shared(2, 2);
SELECT locktype, classid, objid, objsubid, mode, granted
FROM pg_locks WHERE locktype = 'advisory'
ORDER BY classid, objid, objsubid;
SELECT
pg_advisory_unlock(1), pg_advisory_unlock(1),
pg_advisory_unlock_shared(2), pg_advisory_unlock_shared(2),
pg_advisory_unlock(1, 1), pg_advisory_unlock(1, 1),
pg_advisory_unlock_shared(2, 2), pg_advisory_unlock_shared(2, 2);
SELECT count(*) FROM pg_locks WHERE locktype = 'advisory';
-- .. and releasing them all at once
SELECT
pg_advisory_lock(1), pg_advisory_lock(1),
pg_advisory_lock_shared(2), pg_advisory_lock_shared(2),
pg_advisory_lock(1, 1), pg_advisory_lock(1, 1),
pg_advisory_lock_shared(2, 2), pg_advisory_lock_shared(2, 2);
SELECT locktype, classid, objid, objsubid, mode, granted
FROM pg_locks WHERE locktype = 'advisory'
ORDER BY classid, objid, objsubid;
SELECT pg_advisory_unlock_all();
SELECT count(*) FROM pg_locks WHERE locktype = 'advisory';
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