InnoDB: Make intermediate COMMITs in ALTER TABLE more robust (Bug #6633)

innobase/include/lock0lock.h:
  Replaced lock_get_ix_table() with lock_get_table().
innobase/lock/lock0lock.c:
  Replaced lock_get_ix_table() with lock_get_table().
innobase/include/row0mysql.h:
  row_lock_table_for_mysql(): Added parameter mode.
innobase/row/row0mysql.c:
  row_lock_table_for_mysql(): Added parameter mode.
sql/ha_innodb.cc:
  ha_innobase::write_row(): Make ALTER TABLE commits more robust:
  account for conversions from non-InnoDB format,
  do not attempt to commit if there are other than
  a single IX or IS lock on the source table, and
  the source table is in InnoDB format.  This
  prohibits intermediate commits for OPTIMIZE TABLE
  if the table contains an auto_increment field.

1 files changed, 48 insertions, 12 deletions

diff --git a/sql/ha_innodb.cc b/sql/ha_innodb.cc
index 2515b4956d0..2aaf69bd208 100644
--- a/sql/ha_innodb.cc
+++ b/sql/ha_innodb.cc
@@ -2324,20 +2324,55 @@ ha_innobase::write_row(
 		position in the source table need not be adjusted after the
 		intermediate COMMIT, since writes by other transactions are
 		being blocked by a MySQL table lock TL_WRITE_ALLOW_READ. */
-		ut_a(prebuilt->trx->mysql_n_tables_locked == 2);
-		ut_a(UT_LIST_GET_LEN(prebuilt->trx->trx_locks) >= 2);
-		dict_table_t* table = lock_get_ix_table(
-				UT_LIST_GET_FIRST(prebuilt->trx->trx_locks));
+
+		dict_table_t*	table;
+		ibool		mode;
+
 		num_write_row = 0;
+
 		/* Commit the transaction.  This will release the table
 		locks, so they have to be acquired again. */
-		innobase_commit(user_thd, prebuilt->trx);
-		/* Note that this transaction is still active. */
-		user_thd->transaction.all.innodb_active_trans = 1;
-		/* Re-acquire the IX table lock on the source table. */
-		row_lock_table_for_mysql(prebuilt, table);
-		/* We will need an IX lock on the destination table. */
-	        prebuilt->sql_stat_start = TRUE;
+		switch (prebuilt->trx->mysql_n_tables_locked) {
+		case 1:
+			/* Altering to InnoDB format */
+			innobase_commit(user_thd, prebuilt->trx);
+			/* Note that this transaction is still active. */
+			user_thd->transaction.all.innodb_active_trans = 1;
+			/* We will need an IX lock on the destination table. */
+		        prebuilt->sql_stat_start = TRUE;
+			break;
+		case 2:
+			/* Altering an InnoDB table */
+			ut_a(UT_LIST_GET_LEN(prebuilt->trx->trx_locks) >= 2);
+			table = lock_get_table(
+				UT_LIST_GET_FIRST(prebuilt->trx->trx_locks),
+				&mode);
+			if (!table) {
+				goto no_commit;
+			}
+
+			/* Commit the transaction.  This will release the table
+			locks, so they have to be acquired again. */
+			innobase_commit(user_thd, prebuilt->trx);
+			/* Note that this transaction is still active. */
+			user_thd->transaction.all.innodb_active_trans = 1;
+			/* Re-acquire the table lock on the source table. */
+			row_lock_table_for_mysql(prebuilt, table, mode);
+			/* We will need an IX lock on the destination table. */
+		        prebuilt->sql_stat_start = TRUE;
+			break;
+		default:
+		no_commit:
+			/* Unknown situation: do nothing (no commit) */
+			/*
+			ut_print_timestamp(stderr);
+			fprintf(stderr,
+				"  InnoDB error: ALTER TABLE is holding lock"
+				" on %lu tables!\n",
+				prebuilt->trx->mysql_n_tables_locked);
+			*/
+			break;
+		}
 	}
 
 	num_write_row++;
@@ -5015,7 +5050,8 @@ ha_innobase::external_lock(
 			if (thd->in_lock_tables &&
 			    thd->variables.innodb_table_locks) {
 				ulint	error;
-				error = row_lock_table_for_mysql(prebuilt, 0);
+				error = row_lock_table_for_mysql(prebuilt,
+							NULL, LOCK_TABLE_EXP);
 
 				if (error != DB_SUCCESS) {
 					error = convert_error_code_to_mysql(