Set Variables

• A SET statement can contain multiple variable assignments, separated by commas.
  • When several system variables are set, the most recent GLOBAL or SESSION modifier in the statement is used for following variables that have no modifier specified.
  • For example:

    SET sort_buffer_size=10000;

    SET @@local.sort_buffer_size=10000;

    SET GLOBAL sort_buffer_size=1000000, SESSION sort_buffer_size=1000000;

    SET @@sort_buffer_size=1000000;

    SET @@global.sort_buffer_size=1000000, @@local.sort_buffer_size=1000000;

• Values can take the form of an expression.
  • For example:

    SET sort_buffer_size = 10 * 1024 * 1024;

When do variables take effect?

---

---

© 2007 John Michael Pierobon

Notes