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https://dev.mysql.com/doc/internals/en/transaction-overview.html
As operations are performed the storage engine will have to implement some form of versioning or logging to permit a rollback of all operations executed within the transaction. Transactions are not explicitly started on the storage engine level, ...
https://dev.mysql.com/doc/internals/en/transactions-current-situation.html
Finally, SQL statements that work with nontransactional engines also have no effect on the transaction state of the connection. Nowadays a statement transaction is started for each statement that accesses transactional tables or uses the binary log. Commits of statement transactions are not durable -- each statement transaction is nested in the normal transaction, and if the normal transaction is rolled back, the effects of all enclosed statement transactions are undone as ...
https://dev.mysql.com/doc/internals/en/transactions-data-layout.html
These members correspond to the statement and normal transactions respectively: thd->transaction.stmt contains a list of engines that are participating in the given statement thd->transaction.all contains a list of engines that have participated in ...Each element of the list contains a pointer to the storage engine, engine-specific transactional data, and engine-specific transaction ...
https://dev.mysql.com/doc/internals/en/tuning-trace-purging.html
A stored routine may have a loop which executes many substatements and thus generates many traces, which would use a lot of memory; proper OFFSET and LIMIT can restrict tracing to one iteration of the loop for example. This is done with SET ...
https://dev.mysql.com/doc/internals/en/unsafe-statements.html
UDFs: since we have no control over what the UDF does, it may be doing something unsafe. NOTE: the following list is incomplete; it does not take into account changes made in 2010 or later (roughly). An unsafe statement will be logged in row format ...
https://dev.mysql.com/doc/internals/en/user-level-locks.html
MySQL Internals mailing list, 10 Dec 2007: http://lists.mysql.com/internals/35220 One limitation of user-level locks is that a thread can have one lock at a time only. User-level locks are controlled with the SQL functions GET_LOCK(str,timeout) ...
https://dev.mysql.com/doc/internals/en/variation-of-protocol-option.html
We have a lot of tests running very similar and extremely simple SQL just for the creation of a situation to be tested, check of table content, etc. It is usual to run tests with and without the mysql-test-run.pl startup option "--ps-protocol". And ...
https://dev.mysql.com/doc/internals/en/vio-directory.html
The idea is that in the main modules one won't have to write separate bits of code for each protocol. The VIO routines are wrappers for the various network I/O calls that happen with different protocols. Thus vio's purpose is somewhat like the ...
https://dev.mysql.com/doc/internals/en/writing-services-for-use-from-plugins.html
A service named xxx will have a file named service_xxx.h in the include/mysql directory. Services are implemented by modifying server code in the sql directory to register the service in the plugin code, and by providing interface files in the ...
https://dev.mysql.com/doc/internals/en/x-protocol-lifecycle-lifecycle.html
Topics in this section: Connection Session Stages of Session Setup Authentication Pipelining Max Message Length Extensions The following list describes some of the terms introduced in this section: Transport Transport layer that exchanges data: TCP ...