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.
Created a test suite 'innodb' under mysql-test/suite/innodb for the innodb plugin tests.
test suite 'innodb' has tests only which are not under any other mysql-test suites.
Total 14 testcases are added to the test suite.
Note: the patches in storage/innodb_plugin/mysql-test/patches are not applied yet
