MDEV-21921 Make transaction_isolation and transaction_read_only into system variables

In MariaDB, we have a confusing problem where:
* The transaction_isolation option can be set in a configuration file, but it cannot be set dynamically.
* The tx_isolation system variable can be set dynamically, but it cannot be set in a configuration file.

Therefore, we have two different names for the same thing in different contexts. This is needlessly confusing, and it complicates the documentation. The same thing applys for transaction_read_only.

MySQL 5.7 solved this problem by making them into system variables. https://dev.mysql.com/doc/relnotes/mysql/5.7/en/news-5-7-20.html

This commit takes a similar approach by adding new system variables and marking the original ones as deprecated. This commit also resolves some legacy problems related to SET STATEMENT and transaction_isolation.

1 files changed, 2 insertions, 2 deletions

diff --git a/mysql-test/main/unsafe_binlog_innodb.test b/mysql-test/main/unsafe_binlog_innodb.test
index abd2c58de30..0f57c60cd61 100644
--- a/mysql-test/main/unsafe_binlog_innodb.test
+++ b/mysql-test/main/unsafe_binlog_innodb.test
@@ -15,10 +15,10 @@ let $engine_type= InnoDB;
 
 SET @save_timeout = @@GLOBAL.innodb_lock_wait_timeout;
 SET GLOBAL innodb_lock_wait_timeout = 1;
-SET @save_isolation = @@GLOBAL.tx_isolation;
+SET @save_isolation = @@GLOBAL.transaction_isolation;
 SET GLOBAL TRANSACTION ISOLATION LEVEL READ COMMITTED;
 
 --source include/unsafe_binlog.inc
 
 SET GLOBAL innodb_lock_wait_timeout = @save_timeout;
-SET GLOBAL tx_isolation = @save_isolation;
+SET GLOBAL transaction_isolation = @save_isolation;