MariaDB server is a community developed fork of MySQL server. Started by core members of the original MySQL team, MariaDB actively works with outside developers to deliver the most featureful, stable, and sanely licensed open SQL server in the industry.
Split THD by used arenas: shorter arena have its own class and its own members (if there are any THD members that live only on shorter arenas);
Item and Field are dynamically allocated (in optimizer f.ex.): they can be short-lived or long-lived. Use reference counting inside container. I.e. Item will not be destructed until container is not destructed. Containers are: List, Item itself, etc.
Split
THDby used arenas: shorter arena have its own class and its own members (if there are anyTHDmembers that live only on shorter arenas);ItemandFieldare dynamically allocated (in optimizer f.ex.): they can be short-lived or long-lived. Use reference counting inside container. I.e.Itemwill not be destructed until container is not destructed. Containers are:List,Itemitself, etc.