lockdefs.h

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/*-------------------------------------------------------------------------
 *
 * lockdefs.h
 *     Frontend exposed parts of postgres' low level lock mechanism
 *
 * The split between lockdefs.h and lock.h is not very principled. This file
 * contains definition that have to (indirectly) be available when included by
 * FRONTEND code.
 *
 * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/storage/lockdefs.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef LOCKDEFS_H_
#define LOCKDEFS_H_

/*
 * 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;

/*
 * These are the valid values of type LOCKMODE for all the standard lock
 * methods (both DEFAULT and USER).
 */

/* NoLock is not a lock mode, but a flag value meaning "don't get a lock" */
#define NoLock                  0

#define AccessShareLock         1       /* SELECT */
#define RowShareLock            2       /* SELECT FOR UPDATE/FOR SHARE */
#define RowExclusiveLock        3       /* INSERT, UPDATE, DELETE */
#define ShareUpdateExclusiveLock 4      /* VACUUM (non-FULL),ANALYZE, CREATE
                                         * INDEX CONCURRENTLY */
#define ShareLock               5       /* CREATE INDEX (WITHOUT CONCURRENTLY) */
#define ShareRowExclusiveLock   6       /* like EXCLUSIVE MODE, but allows ROW
                                         * SHARE */
#define ExclusiveLock           7       /* blocks ROW SHARE/SELECT...FOR
                                         * UPDATE */
#define AccessExclusiveLock     8       /* ALTER TABLE, DROP TABLE, VACUUM
                                         * FULL, and unqualified LOCK TABLE */

typedef struct xl_standby_lock
{
    TransactionId xid;          /* xid of holder of AccessExclusiveLock */
    Oid         dbOid;
    Oid         relOid;
} xl_standby_lock;

#endif /* LOCKDEF_H_ */