Search Results
https://dev.mysql.com/doc/internals/en/make-test-protocols-more-understandable.html
Please have the test write comments into the protocol if this makes the surrounding protocol content much more understandable. This is especially true for tests that do the following: Suppress the printing of SQL statements and result sets Work ...
https://dev.mysql.com/doc/internals/en/mismatch-of-focus-of-test-and-code-sequence.html
CREATE TABLE t1 ( id INT NOT NULL AUTO_INCREMENT, my_column VARCHAR(30), name LONGTEXT, PRIMARY KEY (id)); INSERT INTO t1(my_column,name) VALUES('2','two'); INSERT INTO t1(my_column,name) VALUES('1','one'); INSERT INTO t1(my_column,name) ...
https://dev.mysql.com/doc/internals/en/mysql-specific-cmake-macros.html
The InnoDB storage engine has this option starting with MySQL 5.5.5. Few plugins need this, typically mandatory storage engines that depend on internal structures and on the EMBEDDED_SERVER flag. Supports optional DESTINATION option which indicates ...
https://dev.mysql.com/doc/internals/en/optimizer-constant-propagation.html
Probably they should not apply for LIKE either, but that's a story for another day. Constant propagation happens in a loop, so the output from one propagation step can be input for the next step.
https://dev.mysql.com/doc/internals/en/optimizer-definitions.html
This description uses a narrow definition: The optimizer is the set of routines which decide what execution path the DBMS should take for queries. To make that easy, this description includes notes referring to the relevant file and routine, such ...MySQL changes these routines frequently, so you should compare what is said here with what's in the current source ...
https://dev.mysql.com/doc/internals/en/optimizer-folding-constants.html
A transformation takes place for this expression: WHERE column1 = 1 + 2 which becomes: WHERE column1 = 3 Before you say, “but I never would write 1 + 2 in the first place”, remember what was said earlier about constant propagation. It is quite ...
https://dev.mysql.com/doc/internals/en/optimizer-order-by-clauses.html
The fact that ordering takes place by column2 values does not affect the choice of driver in this case. In general, the optimizer will skip the sort procedure for the ORDER BY clause if it sees that the rows will be in order anyway. For the query: ...
https://dev.mysql.com/doc/internals/en/position.html
Synopsis virtual void position ( record); const byte * record ; Description This is the position method. Purpose Provide the MySQL server with position/offset information for last-read row. position() is called after each call to rnd_next() if the ...
https://dev.mysql.com/doc/internals/en/prepared-stored-reexecution.html
The second aspect is that a dedicated block allocator (memory root) is used to store the parsed tree, and the memory allocated in this memory root is freed only when the parsed tree is destroyed. Later this memory root will be denoted as the ...
https://dev.mysql.com/doc/internals/en/preventing-use-of-optimizer-trace.html
If for some reason, as DBA of a MySQL Server, you wish to prevent all users from seeing traces of their queries, start the server with these options: --maximum-optimizer-trace-max-mem-size=0 --optimizer-trace-max-mem-size=0 This sets the maximum ...