MySQL 5.6 Replication Performance
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You can monitor the MySQL error log, slow query log, and the general log. The MySQL error log is generated by default; you can generate the slow query and general logs by setting parameters in your DB parameter group.
You can also access MySQL logs by directing the logs to a database table in the main database and querying that table. You can use the mysqlbinlog utility to download a binary log. The MySQL error log mysqlbinlog mysql 56 written to the mysql-error. You can view mysql-error. Each log file has the hour it was generated in UTC appended to its name.
The log files also have a timestamp that helps you determine when the log entries were written. MySQL writes to the error log only on startup, shutdown, and when it encounters errors. A DB instance can go hours or days without new entries being written to the error log. If you see no recent entries, it's because the server did not encounter an error that would result in a log entry.
The MySQL slow query log and the general log can be written to a file or a database table by setting parameters in your DB parameter group. To create the slow query log, set to 1. The default is 0. To create the general log, set to 1.
To prevent fast-running queries from being logged in the slow query log, specify a value for mysqlbinlog mysql 56 shortest query execution time to be logged, in seconds. The default is 10 seconds; the minimum is 0. To log all queries that do not use an index to the slow query log, set to 1. FILE — Write both general and slow query logs to the file system. Log files are rotated hourly.
When logging is enabled, Amazon RDS rotates table logs or deletes log files at regular intervals. This measure is a precaution to reduce the possibility of a large log file either blocking database use or affecting performance. When FILE logging is enabled, log files are examined every hour and log files older than 24 hours are deleted.
In some cases, the mysqlbinlog mysql 56 combined log file size after the deletion might exceed the threshold of 2 percent of a DB instance's allocated space.
In these cases, the largest log files are deleted until the log file size no longer exceeds the threshold. This rotation occurs if the space used by the table logs is more than 20 percent of the allocated storage space or the size of all logs combined is greater than 10 GB. If the amount of space used mysqlbinlog mysql 56 a DB instance is greater than 90 percent of the DB instance's allocated storage space, then the thresholds for log rotation are reduced.
Log mysqlbinlog mysql 56 are then rotated if the space used by the table logs is more than 10 percent of the allocated storage space or the size of mysqlbinlog mysql 56 logs combined is mysqlbinlog mysql 56 than 5 GB. When log tables are rotated, the current log table is copied to a backup log table and the entries in the current log table are removed.
If the backup log table already exists, then it is deleted before the current log table is copied to the backup. You can query the backup log table if needed. The backup log table for the mysql. You can rotate the mysql. Like the MySQL error log, these log files are rotated hourly. The log files that were mysqlbinlog mysql 56 during the previous 24 hours are retained. For more information about the slow query and general logs, go to the following topics in the MySQL documentation:.
The Slow Query Log. The General Query Log. With CloudWatch Logs, you can perform real-time analysis of the log data, and use CloudWatch to create alarms and view metrics. You can use CloudWatch Logs to store your log records in highly durable storage. Open the Amazon RDS console at https: Open the Log exports section, and then choose the logs you want to start publishing to Mysqlbinlog mysql 56 Logs.
You can call either the modify-db-instance or create-db-instance commands with the following parameters:. The MySQL slow query log, error log, and the general log file sizes are constrained to no more than 2 percent of the allocated storage space for a DB instance.
To maintain this threshold, logs are automatically rotated every hour and log files older than 24 hours are removed. If the combined log file size exceeds the threshold after removing old log files, then the largest log files are deleted until the log file size no longer exceeds the threshold.
For MySQL version 5. General queries are then logged to the mysql. You can query the tables to access the log information. Enabling this logging increases the amount of data written to the database, which can degrade performance. Both the general log and the slow query logs mysqlbinlog mysql 56 disabled by default. Log tables keep growing until the respective mysqlbinlog mysql 56 activities are turned off by resetting the appropriate parameter to 0.
A large amount of data often accumulates over time, which can use up a considerable percentage of your allocated storage space.
Amazon RDS does not allow you to truncate the log tables, but you can move their contents. Mysqlbinlog mysql 56 a table saves its contents to a backup mysqlbinlog mysql 56 and then creates a new empty log table.
To completely remove the old data and reclaim the disk space, call the appropriate procedure twice in succession. The default binary logging format is mixed. Setting the binary logging format to row-based mysqlbinlog mysql 56 result in very large binary log files. Large binary log files reduce the amount of storage available for a DB instance and can increase the amount of time to perform a restore operation mysqlbinlog mysql 56 a DB instance.
Choose Edit Parameters to modify the parameters in the DB parameter group. If you want to specify different binary logging formats for different MySQL 5. This parameter group identifies the different logging format and assigns that DB parameter group to the intended DB instances.
The binary log is downloaded to your local computer, where you can perform actions such as replaying the log using the mysql utility. To run the mysqlbinlog mysql 56 utility against an Amazon RDS instance, use the following options:.
Specify the --read-from-remote-server option. Mysqlbinlog mysql 56 the Mysqlbinlog mysql 56 name from the endpoint of the instance.
Specify the port used by the instance. Specify a MySQL user that has been granted the replication slave permission. Specify the password for the user, or omit a password value so that the utility mysqlbinlog mysql 56 you for a password. To have the file downloaded in binary format, specify the --raw option. Specify the local file to receive the raw output.
Specify the names of one or more binary log files. For more information about mysqlbinlog options, go to mysqlbinlog - Utility for Processing Binary Log Files. Amazon RDS normally purges a binary log as soon as possible, but the binary log must still be available on the instance to be accessed by mysqlbinlog. To specify the number of hours for RDS to retain binary logs, use the mysql.
After you set the retention period, monitor storage usage for the DB instance to ensure that the retained binary logs don't take up too much storage.
Table logs are rotated during a database version upgrade. Mysqlbinlog mysql 56 Setting the binary logging format to row-based can result in very large binary log files. Important Changing the default. To stream the binary log files, specify the --stop-never option.