database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-28 23:42:10 +03:00
Code Activity

Simplify shared-memory lock data structures as per recent discussion:

Browse Source 
it is sufficient to track whether a backend holds a lock or not, and
store information about transaction vs. session locks only in the
inside-the-backend LocalLockTable.  Since there can now be but one
PROCLOCK per lock per backend, LockCountMyLocks() is no longer needed,
thus eliminating some O(N^2) behavior when a backend holds many locks.
Also simplify the LockAcquire/LockRelease API by passing just a
'sessionLock' boolean instead of a transaction ID.  The previous API
was designed with the idea that per-transaction lock holding would be
important for subtransactions, but now that we have subtransactions we
know that this is unwanted.  While at it, add an 'isTempObject' parameter
to LockAcquire to indicate whether the lock is being taken on a temp
table.  This is not used just yet, but will be needed shortly for
two-phase commit.
This commit is contained in:
Tom Lane
2005-06-14 22:15:33 +00:00
parent f5835b4b8d
commit 8563ccae2c
8 changed files with 221 additions and 244 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
contrib/userlock/user_locks.c
View File

@ -33,8 +33,8 @@ user_lock(uint32 id1, uint32 id2, LOCKMODE lockmode)
SET_LOCKTAG_USERLOCK(tag, id1, id2);
return (LockAcquire(USER_LOCKMETHOD, &tag, InvalidTransactionId,
lockmode, true) != LOCKACQUIRE_NOT_AVAIL);
return (LockAcquire(USER_LOCKMETHOD, &tag, false,
lockmode, true, true) != LOCKACQUIRE_NOT_AVAIL);
}
int
@ -44,7 +44,7 @@ user_unlock(uint32 id1, uint32 id2, LOCKMODE lockmode)
SET_LOCKTAG_USERLOCK(tag, id1, id2);
return LockRelease(USER_LOCKMETHOD, &tag, InvalidTransactionId, lockmode);
return LockRelease(USER_LOCKMETHOD, &tag, lockmode, true);
}
int