Commit 79eac42c authored by Howard Chu's avatar Howard Chu
Browse files

s/MDB_NORDLOCK/MDB_NOLOCK/

Leave all lock management to the caller.
parent a1685c3e
......@@ -269,8 +269,8 @@ typedef void (MDB_rel_func)(MDB_val *item, void *oldptr, void *newptr, void *rel
#define MDB_MAPASYNC 0x100000
/** tie reader locktable slots to #MDB_txn objects instead of to threads */
#define MDB_NOTLS 0x200000
/** for #MDB_RDONLY env, don't use reader locktable, caller must manage read/write concurrency */
#define MDB_NORDLOCK 0x400000
/** don't do any locking, caller must manage their own locks */
#define MDB_NOLOCK 0x400000
/** @} */
/** @defgroup mdb_dbi_open Database Flags
......@@ -527,11 +527,13 @@ int mdb_env_create(MDB_env **env);
* user threads over individual OS threads need this option. Such an
* application must also serialize the write transactions in an OS
* thread, since MDB's write locking is unaware of the user threads.
* <li>#MDB_NORDLOCK
* Don't use the reader locktable at all. This flag is only valid
* with #MDB_RDONLY. MDB will use no read locks. If other processes
* may be opening the environment with write access, the callers
* must manage read/write locks themselves.
* <li>#MDB_NOLOCK
* Don't do any locking. If concurrent access is anticipated, the
* caller must manage all concurrency itself. For proper operation
* the caller must enforce single-writer semantics, and must ensure
* that no readers are using old transactions while a writer is
* active. The simplest approach is to use an exclusive lock so that
* no readers may be active at all when a writer begins.
* </ul>
* @param[in] mode The UNIX permissions to set on created files. This parameter
* is ignored on Windows.
......
......@@ -425,7 +425,8 @@ typedef uint16_t indx_t;
*
* If #MDB_NOTLS is set, the slot address is not saved in thread-specific data.
*
* No reader table is used if the database is on a read-only filesystem.
* No reader table is used if the database is on a read-only filesystem, or
* if #MDB_NOLOCK is set.
*
* Since the database uses multi-version concurrency control, readers don't
* actually need any locking. This table is used to keep track of which
......@@ -1572,12 +1573,14 @@ mdb_find_oldest(MDB_txn *txn)
{
int i;
txnid_t mr, oldest = txn->mt_txnid - 1;
MDB_reader *r = txn->mt_env->me_txns->mti_readers;
for (i = txn->mt_env->me_txns->mti_numreaders; --i >= 0; ) {
if (r[i].mr_pid) {
mr = r[i].mr_txnid;
if (oldest > mr)
oldest = mr;
if (txn->mt_env->me_txns) {
MDB_reader *r = txn->mt_env->me_txns->mti_readers;
for (i = txn->mt_env->me_txns->mti_numreaders; --i >= 0; ) {
if (r[i].mr_pid) {
mr = r[i].mr_txnid;
if (oldest > mr)
oldest = mr;
}
}
}
return oldest;
......@@ -2174,10 +2177,15 @@ mdb_txn_renew0(MDB_txn *txn)
meta = env->me_metas[txn->mt_txnid & 1];
}
} else {
LOCK_MUTEX_W(env);
if (env->me_txns) {
LOCK_MUTEX_W(env);
txn->mt_txnid = env->me_txns->mti_txnid;
meta = env->me_metas[txn->mt_txnid & 1];
txn->mt_txnid = env->me_txns->mti_txnid;
meta = env->me_metas[txn->mt_txnid & 1];
} else {
meta = env->me_metas[ mdb_env_pick_meta(env) ];
txn->mt_txnid = meta->mm_txnid;
}
txn->mt_txnid++;
#if MDB_DEBUG
if (txn->mt_txnid == mdb_debug_start)
......@@ -2417,7 +2425,8 @@ mdb_txn_reset0(MDB_txn *txn, const char *act)
env->me_txn = NULL;
/* The writer mutex was locked in mdb_txn_begin. */
UNLOCK_MUTEX_W(env);
if (env->me_txns)
UNLOCK_MUTEX_W(env);
}
}
......@@ -2934,7 +2943,8 @@ done:
env->me_txn = NULL;
mdb_dbis_update(txn, 1);
UNLOCK_MUTEX_W(env);
if (env->me_txns)
UNLOCK_MUTEX_W(env);
free(txn);
return MDB_SUCCESS;
......@@ -3180,7 +3190,8 @@ done:
* readers will get consistent data regardless of how fresh or
* how stale their view of these values is.
*/
env->me_txns->mti_txnid = txn->mt_txnid;
if (env->me_txns)
env->me_txns->mti_txnid = txn->mt_txnid;
return MDB_SUCCESS;
}
......@@ -3900,7 +3911,7 @@ fail:
* environment and re-opening it with the new flags.
*/
#define CHANGEABLE (MDB_NOSYNC|MDB_NOMETASYNC|MDB_MAPASYNC)
#define CHANGELESS (MDB_FIXEDMAP|MDB_NOSUBDIR|MDB_RDONLY|MDB_WRITEMAP|MDB_NOTLS|MDB_NORDLOCK)
#define CHANGELESS (MDB_FIXEDMAP|MDB_NOSUBDIR|MDB_RDONLY|MDB_WRITEMAP|MDB_NOTLS|MDB_NOLOCK)
int
mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mdb_mode_t mode)
......@@ -3953,7 +3964,7 @@ mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mdb_mode_t mode
}
/* For RDONLY, get lockfile after we know datafile exists */
if (!F_ISSET(flags, MDB_RDONLY)) {
if (!(flags & (MDB_RDONLY|MDB_NOLOCK))) {
rc = mdb_env_setup_locks(env, lpath, mode, &excl);
if (rc)
goto leave;
......@@ -3983,7 +3994,7 @@ mdb_env_open(MDB_env *env, const char *path, unsigned int flags, mdb_mode_t mode
goto leave;
}
if ((flags & (MDB_RDONLY|MDB_NORDLOCK)) == MDB_RDONLY) {
if ((flags & (MDB_RDONLY|MDB_NOLOCK)) == MDB_RDONLY) {
rc = mdb_env_setup_locks(env, lpath, mode, &excl);
if (rc)
goto leave;
......
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