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https://dev.mysql.com/doc/internals/en/optimizer-group-by-related-conditions.html
For example, consider the query SELECT MAX(column1) FROM Table1 WHERE column1 < 'a'; If column1 is indexed, then it's easy to find the highest value by looking for 'a' in the index and going back to the key before that. These are the main ...
https://dev.mysql.com/doc/internals/en/optimizer-partition-selection.html
If a partitioned table is accessed in a series of index lookups (that is, using the ref, eq_ref, or ref_or_null access methods), MySQL checks to see whether it needs to make index lookups in all partitions or that it can limit access to a ...
https://dev.mysql.com/doc/internals/en/rnd-next.html
The Field structure for the table is the key to getting data into buf in a manner that will allow the server to understand it. Purpose Reads the next row from a table and returns it to the server. Synopsis virtual int rnd_next ( buf); byte * buf ; ...
https://dev.mysql.com/doc/internals/en/rnd-pos.html
You can use ha_get_ptr(pos,ref_length) to retrieve whatever key or position you saved when position() was called. Synopsis virtual int rnd_pos ( buf, pos); byte * buf ; byte * pos ; Description This is the rnd_pos method. This is like rnd_next, but ...
https://dev.mysql.com/doc/internals/en/select-select-result.html
The key methods in this class are the following: send_fields sends given item list headers (type, name, etc.). This class has a very important role in SELECT performance with select_result class and classes inherited from it (usually called with a ...
https://dev.mysql.com/doc/internals/en/sha256.html
Authentication::SHA256: Name sha256_password Requires CLIENT_PLUGIN_AUTH If the password is non-empty SHA256 auth method XORs the clients password with the scramble buffers content RSA encrypts that with the server's public key using ...
https://dev.mysql.com/doc/internals/en/system-variables-controlling-trace.html
A brief overview from "mysqld --verbose --help": --optimizer-trace=name Controls tracing of the Optimizer: --optimizer-trace-features=name Enables/disables tracing of selected features of the Optimizer: ...
https://dev.mysql.com/doc/internals/en/x-protocol-lifecycle-lifecycle.html
Extensions If the result of CapabilitiesGet contains a extension key from the table below it supports the feature. Topics in this section: Connection Session Stages of Session Setup Authentication Pipelining Max Message Length Extensions The ...
https://dev.mysql.com/doc/internals/en/x-protocol-notices-notices.html
sever-side generated primary keys (like AUTO_INCREMENT) rows-found, rows-matched, rows-affected CURRENT_SCHEMA Sent after statement that changes the current schema like USE ... Global Notices Global Notices are sent by the server in case of events ...
https://dev.mysql.com/doc/internals/en/x-protocol-use-cases-use-cases.html
Topics in this section: Prepared Statements with Single Round-Trip Streaming Inserts SQL with Multiple Resultsets Inserting CRUD Data in a Batch Cross-Collection Update and Delete Prepared Statements with Single Round-Trip In the MySQL ...