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https://dev.mysql.com/doc/internals/en/innodb-fil-header.html
The word "space" is generic jargon for either "log" or "tablespace". -------- - root - -------- | ---------------------- | | | | -------- -------- - leaf - <--> - leaf - -------- -------- Everyone has seen a B-tree and knows that the entries in the ...
https://dev.mysql.com/doc/internals/en/installation-layout-options.html
In the following table, the CMAKE_INSTALL_PREFIX value is the installation base directory. Many other CMake layout options are interpreted relative to the prefix and their values are relative pathnames.
https://dev.mysql.com/doc/internals/en/item-class.html
To us, the word Item means more than just “thingamabob”; it is a technical term with a precise definition in the context of our source code. In the function category we include operators such as + and ||, because operators are merely functions ...
https://dev.mysql.com/doc/internals/en/library-options.html
The following table shows options that indicate which libraries to use. Parameter configure Option CMake Option readline library --with-readline -DWITH_EDITLINE=1 SSL library --with-ssl=/usr -DWITH_SSL=system zlib library --with-zlib-dir=/usr ...
https://dev.mysql.com/doc/internals/en/myisam-compressed-data-file-layout.html
This chapter describes the layout for the data file of compressed MyISAM tables.
https://dev.mysql.com/doc/internals/en/optimizer-and-relations.html
Here's an example: CREATE TABLE Table1 (s1 INT, s2 INT); CREATE INDEX Index1 ON Table1 (s2); CREATE INDEX Index2 ON Table1 (s1); ... SELECT * FROM Table1 WHERE s1 = 5 AND s2 = 5; When choosing a strategy to solve this query, the optimizer picks s2 = ... An ANDed search has the form condition1 AND condition2, as in this example: WHERE column1 = 'x' AND column2 = 'y' Here, the optimizer's decision process can be described as follows: If (neither condition is indexed) use sequential ...
https://dev.mysql.com/doc/internals/en/optimizer-features-to-trace.html
They are: Greedy search: with a N-table join, this could explore factorial(N) plans Range optimizer Dynamic range optimization (known as "range checked for each record" in EXPLAIN output: each outer row causes a re-run of the range optimizer) ...
https://dev.mysql.com/doc/internals/en/optimizer-index-join-type.html
Consider this query: SELECT column1 FROM Table1; If column1 is indexed, then the optimizer may choose to retrieve the values from the index rather than from the table. For this query: SELECT column1, column2 FROM Table1; the optimizer will use join ...An index which is used this way is called a covering index in most ...
https://dev.mysql.com/doc/internals/en/optimizer-index-merge-join-type.html
7.2.2.5.1 Overview Index Merge is used when table condition can be converted to form: cond_1 OR cond_2 ... OR cond_N The conditions for conversion are that each cond_i can be used for a range scan, and no pair (cond_i, cond_j) uses the same index.
https://dev.mysql.com/doc/internals/en/optimizer-late-nulls-filtering.html
Suppose we have a query plan with table tblX being accessed via the ref access method: tblX.key_part1 = expr1 AND tblX.key_part2 = expr2 AND ... Before performing an index lookup, we determine whether any of the expri values is NULL. If it is, we ...