Description: The ‘gtid_executed’ is a variable in the context of database replication that shows the Global Transaction Identifiers (GTIDs) that have been executed on a server. GTIDs are unique identifiers that allow tracking transactions in a replication environment, facilitating data management and synchronization between master and slave servers. This variable is crucial for maintaining the integrity and consistency of replicated data, as it enables administrators to identify which transactions have been applied and which are still pending. The use of GTIDs simplifies replication setup, as it eliminates the need for manual management of transaction logs, allowing for more efficient recovery in case of failures. Additionally, ‘gtid_executed’ provides a way to audit executed transactions, which is essential for the maintenance and monitoring of databases in production environments. In summary, this variable is a fundamental tool for managing replication in databases, ensuring that transactions are applied in an orderly and controlled manner.
History: The concept of GTID was introduced in MySQL 5.6, released in February 2013, as a significant improvement in database replication. Prior to the implementation of GTIDs, replication relied on binary logs, complicating transaction management and failure recovery. The introduction of GTIDs allowed for a more robust and manageable replication, as each transaction is uniquely identified, facilitating synchronization between servers.
Uses: GTIDs and the ‘gtid_executed’ variable are primarily used in database replication environments to ensure that transactions are applied in an orderly manner and to facilitate failure recovery. They are also used in transaction audits and database change management, allowing administrators to track the status of executed transactions.
Examples: A practical example of using ‘gtid_executed’ is in a replication environment where a master server has multiple slave servers. If a transaction is executed on the master, the ‘gtid_executed’ on the slaves is updated to reflect that the transaction has been applied. This allows administrators to quickly verify the replication status and ensure that all slaves are synchronized with the master.
