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https://dev.mysql.com/doc/internals/en/store-lock.html
Synopsis virtual THR_LOCK_DATA ** store_lock ( thd, to, lock_type); THD * thd ; THR_LOCK_DATA ** to ; enum thr_lock_type lock_type ; Description This is the store_lock method. The idea with handler::store_lock() is the following: The statement ...
https://dev.mysql.com/doc/internals/en/strings-directory.html
Many of the files in this subdirectory are equivalent to well-known functions that appear in most C string libraries. On the other hand, some of the files are MySQL additions or improvements. Often the MySQL changes are attempts to optimize the ...
https://dev.mysql.com/doc/internals/en/subtests.html
At least in cases where your file contains many subtests Mark these subtests for better readability of the script Write also a message into the protocol. And please explain what each subtest checks, unless it is obvious.
https://dev.mysql.com/doc/internals/en/tests-with-several-variants.html
Please think twice before you create engine-specific variants of a test or let runs with ps-protocol/sp-protocol/cursor-protocol/view-protocol happen. They might be of low value and a permanent wasting of resources and/or fail (protocol variants ...
https://dev.mysql.com/doc/internals/en/threads.html
Threads in mysqld can run at four different priorities, defined in mysql_priv.h: #define INTERRUPT_PRIOR 10 #define CONNECT_PRIOR 9 #define WAIT_PRIOR 8 #define QUERY_PRIOR 6 Some threads try to set their priority; others don't. These calls are ...
https://dev.mysql.com/doc/internals/en/too-greedy-test.html
Let's assume we have to check that every new created table causes a row in information_schema.tables. --replace_column 15 <CREATE_TIME> 16 <UPDATE_TIME> 17 <CHECK_TIME> SELECT * FROM information_schema.tables; The SELECT above makes the test ...It ...
https://dev.mysql.com/doc/internals/en/transactions-historical-note.html
MySQL would create a nested transaction at the start of each SQL statement, and destroy (commit or abort) the nested transaction at statement end. "Statement transaction" is a non-standard term that comes from the days when MySQL supported the ...
https://dev.mysql.com/doc/internals/en/transformation-scalar-in.html
To rewrite a scalar IN subquery, the Item_in_subselect::single_value_transformer method is used. The scalar IN subquery will be replaced with an Item_in_optimizer item. On a value request (one of val, val_int, or val_str methods) it evaluates the ...
https://dev.mysql.com/doc/internals/en/tuning-trace-purging.html
For example, OFFSET=0 and LIMIT=5 will use memory to remember 5 traces, so if only the three first are needed, OFFSET=0 and LIMIT=3 is better (tracing stops after LIMIT traces, so the 4th and 5th trace are not created and take up no memory). This ...
https://dev.mysql.com/doc/internals/en/x-protocol-messages-messages.html
In case one command creates an error, all following commands should fail too and therefore it is possible to relate the errors to the right messages. Topics in this section: Message Structure Message Sequence Common Messages Connection Session ...