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https://dev.mysql.com/doc/refman/8.4/en/group-by-functional-dependence.html
The following discussion provides several examples of the ways in which MySQL detects functional dependencies. The examples use this notation: {X} -> {Y} Understand this as “X uniquely determines Y,” which also means that Y is functionally ...
https://dev.mysql.com/doc/refman/8.4/en/group-by-modifiers.html
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 operations. ROLLUP thus enables you to answer questions at multiple levels of ...
https://dev.mysql.com/doc/refman/8.4/en/group-by-optimization.html
The most general way to satisfy a GROUP BY clause is to scan the whole table and create a new temporary table where all rows from each group are consecutive, and then use this temporary table to discover groups and apply aggregate functions (if ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-change-primary.html
This section explains how to change which member of a single-primary group is the primary, using the group_replication_set_as_primary() function, which can be can be run on any member of the group. When this is done, the current primary becomes a ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-deploying-instances.html
In this example, three instances are used for the group, which is the minimum number of instances to create a group. The first step is to deploy at least three instances of MySQL Server, this procedure demonstrates using multiple hosts for the ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-getting-started.html
This section provides a detailed tutorial with the steps required to create a replication group with at least three members. MySQL Group Replication is provided as a plugin for the MySQL server; each server in a group requires configuration and ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-gtids.html
The settings are made automatically on the Group Replication channels when they are created, or when a member server in a replication group is upgraded. Group Replication uses GTIDs (global transaction identifiers) to track exactly which ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-ip-address-permissions.html
These addresses, and the localhost IP address for IPv4 and IPv6 are used to create an automatic Group Replication allowlist. When and only when the XCom communication stack is used for establishing group communications ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-multi-primary-mode.html
While traffic is flowing, transactions can be externalized on some members before the others, especially if some members have less write throughput than others, creating the possibility of stale reads. In multi-primary mode ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-performance.html
Group Replication is designed to create fault-tolerant systems with built-in failure detection and automated recovery. If a member server instance leaves voluntarily or stops communicating with the group, the remaining members agree a ...