Search Results
https://dev.mysql.com/doc/internals/en/determining-logging-format.html
This must be done prior to the call to THD::decide_logging_format() (that is, prior to lock_tables). For each statement, we must determine the logging format: row or statement. At parse time, it is detected if the statement is unsafe to log in ...
https://dev.mysql.com/doc/internals/en/err-instead-of-eof.html
00 05 74 61 62 6c 65 00 0c 08 00 40 00 00 00 fd ..table....@.... 48 04 23 48 59 30 30 30 4e 6f 20 74 61 62 6c 65 H.#HY000No table 73 20 75 73 65 64 s used See how after the column definitions a ERR_Packet is sent: 17 00 00 0d ff ................ 48 ... EXPLAIN SELECT * FROM dual; results in 01 00 00 01 0a 18 00 00 02 03 64 65 66 00 00 00 ...
https://dev.mysql.com/doc/internals/en/huffman-compression.html
One could take all possible values - say of a table column - as "messages". But if there are too many of them, the code tables could become bigger than the uncompressed table. In his article from 1952 Huffman proved that his algorithm uses the least ...
https://dev.mysql.com/doc/internals/en/indexing-overview.html
The information provided to the optimizer helps the optimizer to make better decisions about which index to use or even to skip using an index and instead perform a table scan. Adding index support to a storage engine revolves around two tasks: ...
https://dev.mysql.com/doc/internals/en/logging-transactions-preliminary-rules.html
(PR-causality) If statement A is executed before statement B, and B is logged in statement format, and B reads tables that A may modifies, then B shall be logged after A. In particular, changes to N-tables shall be written to the binary log when ...
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/myisammrg-directory.html
As with other table handlers, you'll find that the *.c files in the myissammrg directory have counterparts in the myisam directory. In fact, this general description of a myisammrg program is almost always true: The myisammrg function checks an ...
https://dev.mysql.com/doc/internals/en/packet-OK_Packet.html
An OK packet is sent from the server to the client to signal successful completion of a command. As of MySQL 5.7.5, OK packes are also used to indicate EOF, and EOF packets are deprecated. Consequently, the server does not send OK packets that ...
https://dev.mysql.com/doc/internals/en/perfect-cleanup.html
Cleaning up becomes much more comfortable and less error prone if you create your "own" database and create all tables there. It checks if there are additional objects like user or tables, modifed system table etc. At the end of the test, you need ...
https://dev.mysql.com/doc/internals/en/select-steps.html
Every select is performed in these base steps: JOIN::prepare Initialization and linking JOIN structure to st_select_lex. fix_fields() for all items (after fix_fields(), we know everything about item).