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https://dev.mysql.com/doc/refman/8.0/en/outer-join-simplification.html
At the parser stage, queries with right outer join operations are converted to equivalent queries containing only left join operations. Table expressions in the FROM clause of a query are simplified in many cases. When the optimizer evaluates plans ...
https://dev.mysql.com/doc/refman/8.0/en/group-by-optimization.html
If the WHERE clause contains range predicates (see the discussion of the range join type in Section 10.8.1, “Optimizing Queries with EXPLAIN”), a Loose Index Scan looks up the first key of each group that satisfies the range conditions, and ...
https://dev.mysql.com/doc/refman/8.0/en/innodb-information-schema-buffer-pool-tables.html
The InnoDB INFORMATION_SCHEMA buffer pool tables provide buffer pool status information and metadata about the pages within the InnoDB buffer pool. The InnoDB INFORMATION_SCHEMA buffer pool tables include those listed below: mysql> SHOW TABLES FROM ...
https://dev.mysql.com/doc/refman/8.0/en/range-optimization.html
In MySQL 8.0, index dive skipping is possible for queries that satisfy all these conditions: The query is for a single table, not a join on multiple tables. Range Optimization of Row Constructor Expressions The optimizer is able to apply the range ... The range access method uses a single index to retrieve a subset of table rows that are contained within one or several index value ...
https://dev.mysql.com/doc/refman/8.0/en/with.html
For queries that execute and thus recurse slowly or in contexts for which there is reason to set the cte_max_recursion_depth value very high, another way to guard against deep recursion is to set a per-session timeout. At the beginning of subqueries ... A common table expression (CTE) is a named temporary result set that exists within the scope of a single statement and that can be referred to later within that statement, possibly multiple ...
https://dev.mysql.com/doc/refman/8.0/en/fulltext-search.html
Previously, MySQL permitted the use of a rollup column with MATCH(), but queries employing this construct performed poorly and with unreliable results. Some examples of such queries are shown here: # MATCH() in SELECT list... MATCH (col1,col2,...) ...
https://dev.mysql.com/doc/refman/8.0/en/mysql-commands.html
If you are running with --safe-updates enabled, status also prints the values for the mysql variables that affect your queries. This is useful when you want to log some queries to a file, but not others. mysql sends each SQL statement that you ...
https://dev.mysql.com/doc/refman/8.0/en/group-replication-adding-instances.html
At this point, the group has one member in it, server s1, which has some data in it. It is now time to expand the group by adding the other two servers configured previously. 20.2.1.6.1 Adding a Second Instance In order to add a second instance, ...
https://dev.mysql.com/doc/refman/8.0/en/mysql-cluster-programs-ndb-config.html
To exclude results from any host except one in particular, use the --host option: $> ./ndb_config --host=198.51.100.176 -f : -r '\n' -q id,type 3:ndbd 5:ndb_mgmd In this example, we also used the short form -q to determine the attributes to be ...
https://dev.mysql.com/doc/refman/8.0/en/partitioning-handling-nulls.html
Partitioning in MySQL does nothing to disallow NULL as the value of a partitioning expression, whether it is a column value or the value of a user-supplied expression. Even though it is permitted to use NULL as the value of an expression that must ...