How can I change optimizer_switch for MariaDB Columnstore 1.2.3-1
Hi all,
I moved from MySQL 5.6 to MariaDB Columnstore 1.2.3-1. My use case is: Do some selects and insert into with innodb tables and then move the data to columnstore tables. But when I use innodb engine, selects are dead slow.
So I had a look at the optimizer_switch. When I look at it with: SHOW GLOBAL VARIABLES LIKE 'optimizer_switch'; The result looks good: index_merge=on,index_merge_union=on,...
When I get my session settings with: SHOW SESSION VARIABLES LIKE 'optimizer_switch'; I get: index_merge=off,index_merge_union=off,...
So I tried to set this parameter to 'on' for my session: SET SESSION optimizer_switch='index_merge=on'; With: SHOW SESSION VARIABLES LIKE 'optimizer_switch'; I get: index_merge=off,index_merge_union=off,...
My questions are: How can I change optimizer_switch in MariaDB Columnstore 1.2.3-1? Or how can I force the system to use the global settings?
Many thanks for your answers...
Best regards Thomas
Answer Answered by Roman Nozdrin in this comment.
Greetings Tomas.
Right now CS uses actual version of MDB but with some additions to speed up analitics. One of this features doesn't allow you to change session optimizer flags but the flags for InnoDB-only queries are as global ones. To continue with your issue I suggest you to start a discussion in our Google Group at https://groups.google.com/forum/#!forum/mariadb-columnstore. Plz add the overview of the procedures you use to move data from innodb to columnstore together with explain plans for innodb only queries.
Regards, Roman
