Merge marko@bk-internal.mysql.com:/home/bk/mysql-4.1

into hundin.mysql.fi:/home/marko/k/mysql-4.1

4 files changed, 152 insertions, 21 deletions

diff --git a/innobase/include/lock0lock.h b/innobase/include/lock0lock.h
index f8435e14d97..ff5b6aae02e 100644
--- a/innobase/include/lock0lock.h
+++ b/innobase/include/lock0lock.h
@@ -463,13 +463,32 @@ lock_rec_hash(
 	ulint	space,	/* in: space */
 	ulint	page_no);/* in: page number */
 /*************************************************************************
-Gets the table covered by an IX table lock. */
+Gets the source table of an ALTER TABLE transaction.  The table must be
+covered by an IX or IS table lock. */
 
 dict_table_t*
-lock_get_ix_table(
-/*==============*/
-			/* out: the table covered by the lock */
-	lock_t*	lock);	/* in: table lock */
+lock_get_src_table(
+/*===============*/
+				/* out: the source table of transaction,
+				if it is covered by an IX or IS table lock;
+				dest if there is no source table, and
+				NULL if the transaction is locking more than
+				two tables or an inconsistency is found */
+	trx_t*		trx,	/* in: transaction */
+	dict_table_t*	dest,	/* in: destination of ALTER TABLE */
+	ulint*		mode);	/* out: lock mode of the source table */
+/*************************************************************************
+Determine if the given table is exclusively "owned" by the given
+transaction, i.e., transaction holds LOCK_IX and possibly LOCK_AUTO_INC
+on the table. */
+
+ibool
+lock_table_exclusive(
+/*=================*/
+				/* out: TRUE if table is only locked by trx,
+				with LOCK_IX, and possibly LOCK_AUTO_INC */
+	dict_table_t*	table,	/* in: table */
+	trx_t*		trx);	/* in: transaction */
 /*************************************************************************
 Checks that a transaction id is sensible, i.e., not in the future. */
 
diff --git a/innobase/include/row0mysql.h b/innobase/include/row0mysql.h
index 73f41dea0da..f47ce74ce37 100644
--- a/innobase/include/row0mysql.h
+++ b/innobase/include/row0mysql.h
@@ -177,10 +177,12 @@ row_lock_table_for_mysql(
 					/* out: error code or DB_SUCCESS */
 	row_prebuilt_t*	prebuilt,	/* in: prebuilt struct in the MySQL
 					table handle */
-	dict_table_t*	table);		/* in: table to LOCK_IX, or NULL
+	dict_table_t*	table,		/* in: table to lock, or NULL
 					if prebuilt->table should be
 					locked as LOCK_TABLE_EXP |
 					prebuilt->select_lock_type */
+	ulint		mode);		/* in: lock mode of table */
+					   
 /*************************************************************************
 Does an insert for MySQL. */
 
diff --git a/innobase/lock/lock0lock.c b/innobase/lock/lock0lock.c
index 78a78c9dd95..16c4ddfd96d 100644
--- a/innobase/lock/lock0lock.c
+++ b/innobase/lock/lock0lock.c
@@ -395,19 +395,6 @@ lock_rec_get_nth_bit(
 	return(ut_bit_get_nth(b, bit_index));
 }	
 
-/*************************************************************************
-Gets the table covered by an IX table lock. */
-
-dict_table_t*
-lock_get_ix_table(
-/*==============*/
-			/* out: the table covered by the lock */
-	lock_t*	lock)	/* in: table lock */
-{
-	ut_a(lock->type_mode == (LOCK_TABLE | LOCK_IX));
-	return(lock->un_member.tab_lock.table);
-}
-
 /*************************************************************************/
 
 #define lock_mutex_enter_kernel()	mutex_enter(&kernel_mutex)
@@ -615,6 +602,128 @@ lock_get_wait(
 }
 
 /*************************************************************************
+Gets the source table of an ALTER TABLE transaction.  The table must be
+covered by an IX or IS table lock. */
+
+dict_table_t*
+lock_get_src_table(
+/*===============*/
+				/* out: the source table of transaction,
+				if it is covered by an IX or IS table lock;
+				dest if there is no source table, and
+				NULL if the transaction is locking more than
+				two tables or an inconsistency is found */
+	trx_t*		trx,	/* in: transaction */
+	dict_table_t*	dest,	/* in: destination of ALTER TABLE */
+	ulint*		mode)	/* out: lock mode of the source table */
+{
+	dict_table_t*	src;
+	lock_t*		lock;
+
+	src = NULL;
+	*mode = LOCK_NONE;
+
+	for (lock = UT_LIST_GET_FIRST(trx->trx_locks);
+	     lock;
+	     lock = UT_LIST_GET_NEXT(trx_locks, lock)) {
+		lock_table_t*	tab_lock;
+		ulint		lock_mode;
+		if (!(lock_get_type(lock) & LOCK_TABLE)) {
+			/* We are only interested in table locks. */
+			continue;
+		}
+		tab_lock = &lock->un_member.tab_lock;
+		if (dest == tab_lock->table) {
+			/* We are not interested in the destination table. */
+			continue;
+		} else if (!src) {
+			/* This presumably is the source table. */
+			src = tab_lock->table;
+			if (UT_LIST_GET_LEN(src->locks) != 1 ||
+			    UT_LIST_GET_FIRST(src->locks) != lock) {
+				/* We only support the case when
+				there is only one lock on this table. */
+				return(NULL);
+			}
+		} else if (src != tab_lock->table) {
+			/* The transaction is locking more than
+			two tables (src and dest): abort */
+			return(NULL);
+		}
+
+		/* Check that the source table is locked by
+		LOCK_IX or LOCK_IS. */
+		lock_mode = lock_get_mode(lock);
+		switch (lock_mode) {
+		case LOCK_IX:
+		case LOCK_IS:
+			if (*mode != LOCK_NONE && *mode != lock_mode) {
+				/* There are multiple locks on src. */
+				return(NULL);
+			}
+			*mode = lock_mode;
+			break;
+		}
+	}
+
+	if (!src) {
+		/* No source table lock found: flag the situation to caller */
+		src = dest;
+	}
+
+	return(src);
+}
+
+/*************************************************************************
+Determine if the given table is exclusively "owned" by the given
+transaction, i.e., transaction holds LOCK_IX and possibly LOCK_AUTO_INC
+on the table. */
+
+ibool
+lock_is_table_exclusive(
+/*====================*/
+				/* out: TRUE if table is only locked by trx,
+				with LOCK_IX, and possibly LOCK_AUTO_INC */
+	dict_table_t*	table,	/* in: table */
+	trx_t*		trx)	/* in: transaction */
+{
+	lock_t*	lock;
+	bool	ok	= FALSE;
+
+	ut_ad(table && trx);
+
+	for (lock = UT_LIST_GET_FIRST(table->locks);
+	     lock;
+	     lock = UT_LIST_GET_NEXT(locks, &lock->un_member.tab_lock)) {
+		if (lock->trx != trx) {
+			/* A lock on the table is held
+			by some other transaction. */
+			return(FALSE);
+		}
+
+		if (!(lock_get_type(lock) & LOCK_TABLE)) {
+			/* We are interested in table locks only. */
+			continue;
+		}
+
+		switch (lock_get_mode(lock)) {
+		case LOCK_IX:
+			ok = TRUE;
+			break;
+		case LOCK_AUTO_INC:
+			/* It is allowed for trx to hold an
+			auto_increment lock. */
+			break;
+		default:
+			/* Other table locks than LOCK_IX are not allowed. */
+			return(FALSE);
+		}
+	}
+
+	return(ok);
+}
+
+/*************************************************************************
 Sets the wait flag of a lock and the back pointer in trx to lock. */
 UNIV_INLINE
 void
diff --git a/innobase/row/row0mysql.c b/innobase/row/row0mysql.c
index 9613da2e286..dec2b19559c 100644
--- a/innobase/row/row0mysql.c
+++ b/innobase/row/row0mysql.c
@@ -782,10 +782,11 @@ row_lock_table_for_mysql(
 					/* out: error code or DB_SUCCESS */
 	row_prebuilt_t*	prebuilt,	/* in: prebuilt struct in the MySQL
 					table handle */
-	dict_table_t*	table)		/* in: table to LOCK_IX, or NULL
+	dict_table_t*	table,		/* in: table to lock, or NULL
 					if prebuilt->table should be
 					locked as LOCK_TABLE_EXP |
 					prebuilt->select_lock_type */
+	ulint		mode)		/* in: lock mode of table */
 {
 	trx_t*		trx 		= prebuilt->trx;
 	que_thr_t*	thr;
@@ -819,7 +820,7 @@ run_again:
 	trx_start_if_not_started(trx);
 
 	if (table) {
-		err = lock_table(0, table, LOCK_IX, thr);
+		err = lock_table(0, table, mode, thr);
 	} else {
 		err = lock_table(LOCK_TABLE_EXP, prebuilt->table,
 			prebuilt->select_lock_type, thr);