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Tom Lane 2004-08-26 17:22:28 +00:00
parent dd9923eb25
commit 51d7e25651
1 changed files with 25 additions and 20 deletions
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45
src/include/storage/lock.h
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@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/storage/lock.h,v 1.79 2004/07/17 03:31:26 tgl Exp $
* $PostgreSQL: pgsql/src/include/storage/lock.h,v 1.80 2004/08/26 17:22:28 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -26,10 +26,10 @@ typedef struct PROC_QUEUE
int size; /* number of entries in list */
} PROC_QUEUE;
/* struct PGPROC is declared in storage/proc.h, but must forward-reference it */
/* struct PGPROC is declared in proc.h, but must forward-reference it */
typedef struct PGPROC PGPROC;
/* GUC variables */
extern int max_locks_per_xact;
#ifdef LOCK_DEBUG
@ -41,6 +41,11 @@ extern bool Debug_deadlocks;
#endif /* LOCK_DEBUG */
/*
* LOCKMODE is an integer (1..N) indicating a lock type. LOCKMASK is a bit
* mask indicating a set of held or requested lock types (the bit 1<<mode
* corresponds to a particular lock mode).
*/
typedef int LOCKMASK;
typedef int LOCKMODE;
/* MAX_LOCKMODES cannot be larger than the # of bits in LOCKMASK */
@ -49,6 +54,11 @@ typedef int LOCKMODE;
#define LOCKBIT_ON(lockmode) (1 << (lockmode))
#define LOCKBIT_OFF(lockmode) (~(1 << (lockmode)))
/*
* There is normally only one lock method, the default one.
* If user locks are enabled, an additional lock method is present.
* Lock methods are identified by LOCKMETHODID.
*/
typedef uint16 LOCKMETHODID;
/* MAX_LOCK_METHODS is the number of distinct lock control tables allowed */
#define MAX_LOCK_METHODS 3
@ -60,18 +70,13 @@ typedef uint16 LOCKMETHODID;
#define LockMethodIsValid(lockmethodid) ((lockmethodid) != INVALID_LOCKMETHOD)
/*
* There is normally only one lock method, the default one.
* If user locks are enabled, an additional lock method is present.
* This is the control structure for a lock table. It lives in shared
* memory. Currently, none of these fields change after startup. In addition
* to the LockMethodData, a lock table has a "lockHash" table holding
* per-locked-object lock information, and a "proclockHash" table holding
* per-lock-holder/waiter lock information.
*
* This is the control structure for a lock table. It
* lives in shared memory. This information is the same
* for all backends.
*
* lockHash -- hash table holding per-locked-object lock information
*
* proclockHash -- hash table holding per-lock-waiter/holder lock information
*
* lockmethod -- the handle used by the lock table's clients to
* lockmethodid -- the handle used by the lock table's clients to
* refer to the type of lock table being used.
*
* numLockModes -- number of lock types (READ,WRITE,etc) that
@ -81,8 +86,7 @@ typedef uint16 LOCKMETHODID;
* type conflicts. conflictTab[i] is a mask with the j-th bit
* turned on if lock types i and j conflict.
*
* masterLock -- synchronizes access to the table
*
* masterLock -- LWLock used to synchronize access to the table
*/
typedef struct LockMethodData
{
@ -156,12 +160,13 @@ typedef struct LOCK
/*
* We may have several different transactions holding or awaiting locks
* on the same lockable object. We need to store some per-waiter/holder
* information for each such holder (or would-be holder).
* on the same lockable object. We need to store some per-holder/waiter
* information for each such holder (or would-be holder). This is kept in
* a PROCLOCK struct.
*
* PROCLOCKTAG is the key information needed to look up a PROCLOCK item in the
* proclock hashtable. A PROCLOCKTAG value uniquely identifies a lock
* holder/waiter.
* proclock hashtable. A PROCLOCKTAG value uniquely identifies the combination
* of a lockable object and a holder/waiter for that object.
*
* There are two possible kinds of proclock tags: a transaction (identified
* both by the PGPROC of the backend running it, and the xact's own ID) and