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https://dev.mysql.com/doc/refman/5.7/en/innodb-analyze-table-complexity.html
The number of indexed columns in a table The number of partitions. Using these parameters, an approximate formula for estimating ANALYZE TABLE complexity would be: The value of innodb_stats_persistent_sample_pages * number of indexed columns in a ...
https://dev.mysql.com/doc/refman/5.7/en/mysql-cluster-ndbinfo-memory-per-fragment.html
Every row having one or more variable-sized, one or more dynamic columns (or both) has a variable-sized part. Each row in an NDB table has a fixed-size part, consisting of a row header, and one or more fixed-size columns. The total free space ...
https://dev.mysql.com/doc/refman/5.7/en/performance-schema-threads-table.html
The INSTRUMENTED and HISTORY column values for new threads are determined by the contents of the setup_actors table. For information about how to use the setup_actors table to control these columns, see Section 25.4.6, “Pre-Filtering by Thread”.
https://dev.mysql.com/doc/refman/5.7/en/request-access.html
This is where the privilege columns in the grant tables come into play. These privileges can come from any of the user, db, tables_priv, columns_priv, or procs_priv tables. (You may find it helpful to refer to Section 6.2.3, “Grant Tables”, ...
https://dev.mysql.com/doc/refman/5.7/en/charset-unicode-conversion.html
When converting utf8mb3 columns to utf8mb4, you need not worry about converting supplementary characters because there are none. In terms of table structure, these are the primary potential incompatibilities: For the variable-length character data ... This section describes issues that you may face when converting character data between the utf8mb3 and utf8mb4 character ...
https://dev.mysql.com/doc/refman/5.7/en/example-auto-increment.html
You can also explicitly assign 0 to the column to generate sequence numbers, unless the NO_AUTO_VALUE_ON_ZERO SQL mode is enabled. For example: INSERT INTO animals (id,name) VALUES(0,'groundhog'); If the column is declared NOT NULL, it is also ...
https://dev.mysql.com/doc/refman/5.7/en/group-by-modifiers.html
ROLLUP has a more complex effect when there are multiple GROUP BY columns. In this case, each time there is a change in value in any but the last grouping column, the query produces an extra super-aggregate summary row. These rows have the country ... The GROUP BY clause permits a WITH ROLLUP modifier that causes summary output to include extra rows that represent higher-level (that is, super-aggregate) summary ...
https://dev.mysql.com/doc/refman/5.7/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/5.7/en/mysql-cluster-limitations-database-objects.html
The maximum number of attributes (that is, columns and indexes) that can belong to a given table is 512. Each BLOB or TEXT column contributes 256 + 8 = 264 bytes to this total; this includes JSON columns. In addition, the maximum offset for a ...
https://dev.mysql.com/doc/refman/5.7/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 ...