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https://dev.mysql.com/doc/internals/en/binlog-row-image.html
To specify the sets of columns, we define the PKE (for Primary Key Equivalent), as follows: If a PK exists, the PKE is equal to the PK. Otherwise, if there exists a UK where all columns have the NOT NULL attribute, then that is the PKE (if there are ... Status of this subsection: finished, not reviewed, not fully implemented 2009-10-21 The sets of columns recorded in the BI and AI are determined by the value of ...
https://dev.mysql.com/doc/internals/en/error-message-adding.html
Never add new parameters (such as %s) to existing error messages. If you need to add new parameters to an existing error message, you can introduce a new error message but continue to use the old error code. The procedure for adding error messages ...
https://dev.mysql.com/doc/internals/en/innodb-infimum-and-supremum-records.html
Initially, they both exist on the root page, but as the index grows, the infimum record will exist on the first or lowest leaf page and the supremum will the last record on the last or greatest key page. “Infimum” and “Supremum” are ...
https://dev.mysql.com/doc/internals/en/logging-transactions-rules-for-create-table-select.html
(Note: currently Bug#47899 breaks this rule) Note: this breaks D-rpl-correct rule, because the slave will have an intermediate state that never existed on the master (namely, a state where the new table exists and is empty).
https://dev.mysql.com/doc/internals/en/negative-tests.html
A "negative" test is a test for which you expect to see a failure. If an error does not occur, that itself indicates a problem. DO NOT FORGET "NEGATIVE" TESTS where we expect to see fine error messages from the server. This section contains just a ...
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/optimizer-order-by-clauses.html
For the query: SELECT column1 FROM Table1 ORDER BY column1; the optimizer will use an index on column1, if it exists. For the query: SELECT column1 FROM Table1 ORDER BY column1+1; the optimizer will use an index on column1, if it exists. In ...
https://dev.mysql.com/doc/internals/en/rows-event.html
repeat rows until event-end Fields table_id (6) -- If the table id is 0x00ffffff it is a dummy event that should have the end of statement flag set that declares that all table maps can be freed. Note if the post_header_length in the ...
https://dev.mysql.com/doc/internals/en/selectexplain.html
mysql_select creates a JOIN for select if it does not already exist (it might already exist because if it called for subquery JOIN can be created in JOIN::optimize of outer query when it decided to calculate the value of the subquery). For an ...
https://dev.mysql.com/doc/internals/en/support-for-update.html
Some storage engines will replace data in-place, while other implementations delete the existing row and append the new row at the end of the data file. Performing an update will depend on row format and storage implementation. Non-indexed storage ...