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https://dev.mysql.com/doc/internals/en/myisam-column-attributes.html
Some further random notes about the new format: In old tables (from MySQL 4.1 and earlier), VARCHAR columns have type MYSQL_TYPE_VAR_STRING, which works exactly like a CHAR with the exception that if you do an ALTER TABLE, it's converted to a true ... Next I'll describe the physical attributes of each column in a ...
https://dev.mysql.com/doc/internals/en/myisam-introduction.html
The main differences are: BLOB values have a length and a memory pointer rather than being stored inline. "True VARCHAR" (a column storage which will be fully implemented in version 5.0) will have a 16-bit length plus the data. MySQL creates files ...
https://dev.mysql.com/doc/internals/en/myisampack.html
This means that finally we may have less code trees than columns. This happens for columns which have the same value in all records. When starting to analyze the existing uncompressed data, it collects distinct column values up to a limit of 8KB. If ...
https://dev.mysql.com/doc/internals/en/mysys-functions.html
Functions in mysys: (For flags see my_sys.h) int my_copy _A((const char *from, const char *to, myf MyFlags)); Copy file from from to to. int my_rename _A((const char *from, const char *to, myf MyFlags)); Rename file from from to to. int my_redel ...
https://dev.mysql.com/doc/internals/en/optimizer-group-by-related-conditions.html
These are the main optimizations that take place for GROUP BY and related items (HAVING, COUNT(), MAX(), MIN(), SUM(), AVG(), DISTINCT()). For the case GROUP BY x ORDER BY x, the optimizer will realize that the ORDER BY is unnecessary, because the ...
https://dev.mysql.com/doc/internals/en/plugin-services-components.html
Within a MySQL source distribution, the header files are located in the include/mysql directory and have an inclusion hierarchy like this: plugin.h includes services.h. On the plugin side of the services interface, the relevant information is ...
https://dev.mysql.com/doc/internals/en/required-server-code-patches.html
There is no dynamic procedure for loading them dynamicly yet like we have for UDFs and plugins. Currently procedures can only be compiled into the server staticly. The build system is not too clever about creating these symlinks for files added ...
https://dev.mysql.com/doc/internals/en/select-special-engines.html
The normal engine can be replaced with such special engines only during the optimization process.
https://dev.mysql.com/doc/internals/en/select-union.html
We will need this object to store in every JOIN structure link on it, but we have not (yet) temporary table structure. Allocate JOIN structures and execute JOIN::prepare() for every SELECT to get full information about types of elements of SELECT ...
https://dev.mysql.com/doc/internals/en/support-for-update.html
Transactional engines may need to compare the buffers to determine what changes have been made for a later rollback. If the table being updated contains timestamp columns, the updating of the timestamp will have to be managed in the update_row() ...