Memory Allocation in the MySQL Server

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MySQL Internals manual/memory allocation/memory Allocation in the MySQL Server (SQL Directory) 9.1 Memory Allocatio N in the MySQL Server (SQL Directory)

The basic logic to use:

All things that is used only for the duration of a query is allocated in Thd::mem_root through Sql_alloc () or Thd->al LOC () except:

• Things. Grow, like string buffers of type string. See sql/sql_string.cc.

• Large blocks of memory used in one state of the the query that can be released early. These is things like sort buffers, range trees, etc.

• Things in libraries is outside of MySQL ' s control (like hash tables).

Things that is needed a longer time should be alllocated with My_malloc () or through another memroot.

Memory Allocation in the MySQL Server