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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/indexing-overview.html
The indexing methods either read rows that match a key, scan a set of rows by index order, or read information directly from the index. Adding index support to a storage engine revolves around two tasks: providing information to the optimizer and ...
https://dev.mysql.com/doc/internals/en/innodb-extra-bytes.html
If you're just trying to read the record, the key bit in the Extra Bytes is 1byte_offs_flag — you need to know if 1byte_offs_flag is 1 (that is, "short 1-byteoffsets") or 0 (that is, "2-byte offsets"). Given a pointer to the Origin, InnoDB finds ...
https://dev.mysql.com/doc/internals/en/optimizer-code-concepts.html
This section discusses key optimizer concepts, terminology, and how these are reflected in the MySQL server source code.
https://dev.mysql.com/doc/internals/en/optimizer-early-nulls-filtering.html
Suppose further that table tblY is accessed via ref or eq_ref access on tblY.key_column = tblX.column or, in the case of ref access using multiple key parts, via ... We make the following inference: (tblY.key_partN = tblX.column) => (tblX.column IS ... Suppose we have a join order such as this one: ..., tblX, ..., tblY, ...
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 ...