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https://dev.mysql.com/doc/refman/8.4/en/mysql-indexes.html
Indexes are used to find rows with specific column values quickly. If the table has an index for the columns in question, MySQL can quickly determine the position to seek to in the middle of the data file without having to look at all the data. If ...Without an index, MySQL must begin with the first row and then read through the entire table to find the relevant ...
https://dev.mysql.com/doc/refman/8.4/en/rewriter-query-rewrite-plugin-reference.html
The plugin communicates information to users by setting the table's message column. replacement The template that indicates how to rewrite statements matching the pattern column value. Load operations (performed by invoking the flush_rewrite_rules() ...Users communicate with the plugin by modifying the set of rules stored in this ...
https://dev.mysql.com/doc/internals/en/myisam-introduction.html
"Filler Bits" = 1 The length of the record header is thus: (1 + number of NULL columns + 7) / 8 bytes After the header, all columns are stored in the order that they were created, which is the same order that you would get from SHOW COLUMNS. Here's ...MySQL creates files named Table1.MYD ("MySQL Data"), Table1.MYI ("MySQL Index"), and Table1.frm ...
https://dev.mysql.com/doc/internals/en/optimizer-partition-pruning.html
Suppose that we have a partitioned table with N columns, using partitioning type p_type and the partitioning function p_func, represented like this: CREATE TABLE t (columns) PARTITION BY p_type(p_func(col1, col2,... Note This process works only if ...Partitions that did not get into this set (that is, those that were pruned away) will not be accessed at all: this is how query execution is made ...
https://dev.mysql.com/doc/refman/8.4/en/dynamic-format.html
Dynamic storage format is used if a MyISAM table contains any variable-length columns (VARCHAR, VARBINARY, BLOB, or TEXT), or if the table was created with the ROW_FORMAT=DYNAMIC table option. If you have fixed-length columns that you access or ...
MySQL 8.4 Reference Manual :: A.11 MySQL 8.4 FAQ: MySQL Chinese, Japanese, and Korean Character Sets
https://dev.mysql.com/doc/refman/8.4/en/faqs-cjk.html
You can obtain this information for a column column_name in the table table_name using the following query: SELECT HEX(column_name) FROM table_name; 3F is the encoding for the ? character; this means that ? is the character actually stored in the ...
https://dev.mysql.com/doc/refman/8.4/en/information-schema-partitions-table.html
The PARTITIONS table has these columns: TABLE_CATALOG The name of the catalog to which the table belongs. The indexing can change as partitions are added, dropped, and reorganized; the number shown is this column reflects the current order, taking ...Each row in this table corresponds to an individual partition or subpartition of a partitioned ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-disk-data-objects.html
It is also possible to specify whether an individual column is stored on disk or in memory by using a STORAGE clause as part of the column's definition in a CREATE TABLE or ALTER TABLE statement. STORAGE DISK causes the column to be stored on disk, ... NDB Cluster Disk Data storage is implemented using the following objects: Tablespace: Acts as containers for other Disk Data ...
https://dev.mysql.com/doc/refman/8.4/en/partitioning-overview.html
The SQL language itself is intended to work independently of any data structures or media underlying the schemas, tables, rows, or columns with which it works. This expression can be a column value, a function acting on one or more column values, or ... This section provides a conceptual overview of partitioning in MySQL ...
https://dev.mysql.com/doc/refman/8.4/en/spatial-index-optimization.html
MySQL permits creation of SPATIAL indexes on NOT NULL geometry-valued columns (see Section 13.4.10, “Creating Spatial Indexes”). The optimizer checks the SRID attribute for indexed columns to determine which spatial reference system (SRS) to ...