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https://dev.mysql.com/doc/internals/en/preventing-use-of-optimizer-trace.html
If for some reason, as DBA of a MySQL Server, you wish to prevent all users from seeing traces of their queries, start the server with these options: --maximum-optimizer-trace-max-mem-size=0 --optimizer-trace-max-mem-size=0 This sets the maximum ...
https://dev.mysql.com/doc/internals/en/include-directory.html
Header (*.h) files for most libraries; includes all header files distributed with the MySQL binary distribution. Note that each individual directory will also have its own *.h files, for including in its own *.c programs. The *.h files in the ...
https://dev.mysql.com/doc/internals/en/index-last.html
Synopsis virtual int index_last ( buf); byte * buf ; Description This is the index_last method. Parameters buf - byte array to be populated with matching row. Usage Advance to last row in index and return row in buffer.
https://dev.mysql.com/doc/internals/en/packed-record-layout.html
pack bits (!= NULL bits!): One bit per packable column: FIELD_BLOB: Set if blob is empty. => The "pack bits" are rounded up to the next byte boundary. Each field is copied verbatim unless packed according to the "pack bits" paragraph.
https://dev.mysql.com/doc/ndbapi/en/mccj-using-clusterj-tables.html
ClusterJ's main purpose is to read, write, and update row data in an existing database, rather than to perform DDL. You can create the employee table that matches this interface, using the following CREATE TABLE statement, in a MySQL client ...
https://dev.mysql.com/doc/x-devapi-userguide/en/setting-the-current-schema.html
A default schema for a session can be specified using the schema attribute in the URI-like connection string or key-value pairs when opening a connection session. The Session class getDefaultSchema() method returns the default schema for the ...
https://dev.mysql.com/doc/internals/en/rnd-init.html
Unlike index_init(), rnd_init() can be called two times without rnd_end() in between (it only makes sense if scan=1). then the second call should prepare for the new table scan (e.g if rnd_init allocates the cursor, second call should position it to ...Synopsis virtual int rnd_init (scan); bool scan ; Description This is the rnd_init ...
https://dev.mysql.com/doc/refman/8.4/en/join.html
A trivial example follows: SELECT * FROM (SELECT 1, 2, 3) AS t1; The maximum number of tables that can be referenced in a single join is 61. INNER JOIN and , (comma) are semantically equivalent in the absence of a join condition: both produce a ...
https://dev.mysql.com/doc/refman/8.4/en/table-locking.html
In this case, the second SELECT statement in the preceding scenario would execute before the UPDATE statement, and would not wait for the first SELECT to finish. But because only one session can write to a table at any one time, for best performance ... InnoDB tables use row-level locking so that multiple sessions and applications can read from and write to the same table simultaneously, without making each other wait or producing inconsistent ...
https://dev.mysql.com/doc/internals/en/capability-negotiation.html
They can agree on: use of status flags use of SQL states for error-codes authentication methods SSL support Compression . To permit an old client to connect to newer servers, the initial handshake contains the MySQL Server version the server's ...