Обсуждение: PGRPROC
if pgproc is used to represent a process and proclock represents a process and its locks of interest, then why does pgproc contain the following information about locks?
/*
* XLOG location of first XLOG record written by this backend's
* current transaction. If backend is not in a transaction or hasn't
* yet modified anything, logRec.xrecoff is zero.
*/
XLogRecPtr logRec;
/* Info about LWLock the process is currently waiting for, if any. */bool lwWaiting; /* true if waiting for an LW lock */bool lwExclusive; /* true if waiting for exclusive access */struct PGPROC *lwWaitLink; /* next waiter for same LW lock *//* Info about lock the process is currently waiting for, if any. *//* waitLock and waitHolder are NULL if not currently waiting. */LOCK *waitLock;
/* Lock object we're sleeping on ... */PROCLOCK *waitHolder;
/* Per-holder info for awaited lock */LOCKMODE waitLockMode;
/* type of lock we're waiting for */LOCKMASK heldLocks;
/* bitmask for lock types already held on* this lock object by this backend */
SHM_QUEUE procHolders;
/* list of PROCLOCK objects for locks held* or awaited by this backend */
};
MSN 8 with e-mail virus protection service: 2 months FREE*
The proclock is structure links locks and procs, either for locks held, or procs waiting for locks. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073