Tag: Binary Log

If you spend all day every day looking after hundreds of MySQL servers, the chances are that you have encountered this problem. And the chances are that if your servers are configured properly (i.e. you have the same configuration the master and the slaves), the error is almost certainly spurious and doesn’t mean what it says it means. So why does it happen? It isn’t entirely clear – it could be a consequence of a hardware glitch, in-flight data corruption in the network layer (though between TCP checksums, and binlog checksums it is vanishingly unlikely to pass through undetected), or ... Read More

Feed: Planet MySQL; Author: Sveta Smirnova; Recovering to a particular time in the past is called Point-In-Time Recovery (PITR). With PITR you can rollback unwanted DELETE without WHERE clause or any other harmful command. PITR with Percona XtraBackup is pretty straightforward and perfectly described in the user manual. You need to restore the data from the backup, then apply all binary logs created or updated after the backup was taken, but skip harmful event(s). However, if your data set is large you may want to recover only the affected database or table. This is possible but you need to be ... Read More

Feed: Planet MySQL; Author: MySQL Performance Blog; For MySQL, MyISAM and InnoDB storage engines are very popular. Currently, we are mostly using InnoDB engines for high reliability and high performance. Apart from those engines, we also have some other alternative engines and they have some nice features in them. In this blog, I am going to explain some of those engines, which I have listed below.  FEDERATED Storage Engine Merge or MRG_MyISAM Engine Blackhole Engine CSV Engine FEDERATED Storage Engine Overview: FEDERATED Storage Engine allows you to access the data remotely without replication and cluster technologies.  Using the FEDERATED tables, ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . The terms master and slave have historically been used in replication, but the terms terms primary and replica are now preferred. The old terms are used throughout the documentation, and in MariaDB commands, although MariaDB 10.5 has begun the process of renaming. The documentation will follow over time. See MDEV-18777 to follow progress on this effort. A safe statement is generally deterministic; in other words the statement will always produce the same result. For example, an INSERT statement producing a random number will most likely produce a different result on the master ... Read More

Feed: MariaDB Knowledge Base Article Feed. Author: . 소개 시퀀스는 CREATE SEQUENCE문에서 지정된 대로 일련의 숫자값을 생성하는 객체입니다. CREATE SEQUENCE는 시퀀스를 생성하고, 생성된 시퀀스는 NEXT VALUE FOR sequence_name으로 호출될 때 마다 새로운 값을 생성합니다.일련번호가 생성되는 방식을 원하는대로 제어하고 싶을 경우에 AUTO INCREMENT를 대신해 사용할 수 있습니다 시퀀스는 값을 캐싱하기 떄문에 경우에 따라 AUTO INCREMENT보다 훨씬 빠를 수 있습니다.(CREATE SEQUENCE문의 CACHE 값 한도만큼 캐싱합니다. 기본값은 1000입니다.) 또 다른 장점은 사용된 모든 시퀀스의 생성된 마지막 값에 접근할 수 있도록 하여, LAST_INSERT_ID()의 한계점 중 하나를 해결했다는 것입니다. 시퀀스 생성 CREATE SEQUENCE문은 시퀀스를 생성하는 데 사용됩니다. 다음은 100에서 시작하여 매번 10 씩 증가하는 시퀀스의 ... Read More

Feed: Planet MySQL; Author: MySQL Performance Blog; Point-In-Time Recovery (PITR) for MySQL databases is an important feature that is essential and covers common use cases, like a recovery to the latest possible transaction or roll-back the database to a specific date before some bad query was executed. Percona Kubernetes Operator for Percona XtraDB Cluster (PXC) added support for PITR in version 1.7, and in this blog post we are going to look into the technical details and decisions we made to implement this feature. Architecture Decisions Store Binary Logs on Object Storage MySQL uses binary logs to perform point-in-time recovery ... Read More

Feed: Planet MySQL; Author: Olivier Dasini; If you are dealing with data, and you most probably are if you are reading this, one of your biggest fears would be not to be able to retrieve them. In a world where data actually surround us, it is critical to be able to retrieve them fast and with the best consistency. Thus, it is always a good idea to have high availability settings in place to avoid loosing your data. However, most of the times, we may wish or we may need to save the database and our data, and be a ... Read More

Feed: Planet MySQL; Author: MyDBOPS; From MySQL 5.7, we had a Multi-threaded Slave (MTS) Applier mechanism called LOGICAL_CLOCK to overcome the problems of parallel replication within a database. To further improve the parallelisation mechanism, from MySQL 8 (5.7.22) we have write-set replication, so before going further , lets look at the difference between Logical clock (LC) and Writeset. LOGICAL_CLOCK Transactions that are part of the same binary log group commit on a master are applied in parallel on a slave. The dependencies between transactions are tracked based on their timestamps to provide additional parallelisation where possible. WRITESET Write-set is a mechanism ... Read More

Feed: Planet MySQL; Author: MySQL Server Dev Team; The MySQL Development Team is happy to announce a new 8.0 Maintenance Release of MySQL Shell AdminAPI – 8.0.23! In addition to several bug fixes and minor changes, some significant enhancements regarding monitoring/troubleshooting and performance were included. MySQL Shell AdminAPI Cluster diagnostics Checking how a Cluster is running and, whenever the cluster is not 100% healthy, perform troubleshooting tasks is certainly one of the main tasks of a DBA. The AdminAPI makes this operation very easy by centralizing the monitoring information in: <Cluster>.status([options]) In this release, we’ve extended the status() command to provide more ... Read More

Feed: Planet MySQL; Author: Severalnines; In a previous blog, we had discussed how to migrate a standalone Moodle setup to scalable setup based on a clustered database.  The next step you will need to think about is the failover mechanism - what do you do if and when your database service goes down.  A failed database server is not unusual if you have MySQL Replication as your backend Moodle database, and if it happens, you will need to find a way to recover your topology by for instance promoting a standby server to become a new primary server. Having automatic ... Read More