In this blog, we will see the very basic thing “I” of “ACID” and an important property of Transaction ie., “ISOLATION”

The isolation defines the way in which the MySQL server (InnoDB) separates each transaction from other concurrent running transaction in the server and also ensures that the transactions are processed in a reliable way. If transactions are not isolated then one transaction could modify the data that another transaction is reading hence creating data inconsistency. Isolation levels determine how isolated the transactions are from each other.

MySQL supports all four the isolation levels that SQL-Standard defines.The four isolation levels are

• READ UNCOMMITTED
• READ COMMITTED
• REPEATABLE READ
• SERIALIZABLE

The Isolation level’s can be set globally or session based on our requirements.

Since MySQL 5.7.5, we have been able to resize dynamically the InnoDB Buffer Pool. This new feature also introduced a new variable — innodb_buffer_pool_chunk_size — which defines the chunk size by which the buffer pool is enlarged or reduced. This variable is not dynamic and if it is incorrectly configured, could lead to undesired situations.

Let’s see first how innodb_buffer_pool_size , innodb_buffer_pool_instances  and innodb_buffer_pool_chunk_size interact:

The buffer pool can hold several instances and each instance is divided into chunks. There is some information that we need to take into account: the number of instances can go from 1 to 64 and the total amount of chunks should not exceed 1000.

So, for a server with 3GB RAM, a buffer pool of 2GB with 8 instances and chunks at default value (128MB) we are going to get 2 chunks per instance:

This means that there will be 16 chunks.

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The Write Ahead Log (WAL) is one of the most important components of a database. All the changes to data files are logged in the WAL (called the redo log in InnoDB). This allows to postpone the moment when the modified pages are flushed to disk, still protecting from data losses.…

MySQL 5.7.8 introduced much improved version of mysqldump, It’s called “mysqlpump”, mysqlpump is much faster than mysqldump with parallel threads capabilities, There are many other compelling reasons for choosing mysqlpump over mysqldump, This blog is about how mysqlpump can be used for good. mysqlpump is relatively a new utility of MySQL and we are confident that Oracle MySQL will invest more to make mysqlpump efficient, we haven’t recommended mysqlpump in production for any of our customers till date, considering several concerns. The following below are mysqlpump features we are really excited about:

• Supports parallel MySQL logical backup, The resource usage efficiency and high performance backups (we love it !)
• Much better orchestration possible – You can backup selected databases, tables, stored programs and user accounts etc.
• By default mysqlpump will not backup performance_schema, sys schema, …

Occasionally we have customers with MyISAM storage engine approaching us to migrate their database to InnoDB, MyISAM is great if you are just an application like web content management system with no multi-user concurrency challenges but what if you are building an highly transactional data web property ? InnoDB is much preferred for such situations, InnoDB provides Row-level locking (Oracle like) for consistent reads on an multi-user concurrent user high performance database application. InnoDB also guarantees maximum data integrity by supporting FOREIGN KEY, We captured below few interesting points to remember while migrating your database from MyISAM to InnoDB :

• Data of InnoDB tables is stored in *.ibd files, deleting those files will permanently corrupt your database
• InnoDB tables consumes more storage space than MyISAM tables .
• Unlike MyISAM, InnoDB is a transactional database engine. In any typical MyISAM …

Generally, when I'm analyzing MySQL Performance on Linux with "localhost" test workloads, I'm configuring client connections to use IP port (loopback) to connect to MySQL Server (and not UNIX socket) -- this is still at least involving IP stack in the game, and if something is going odd on IP, we can be aware ahead about. And indeed, it already helped several times to discover such kind of problems even without network links between client/server (like this one, etc.). However, in the past we also observed a pretty significant difference in QPS results when IP port was used comparing to UNIX socket (communications via UNIX socket were going near 15% faster).. Over a time with newer OL kernel releases this gap became smaller and smaller. But in all such …

In this blog post, we have multiple OLTP performance benchmarking scenarios using sysbench 1.0.14 on InnoDB and MyRocks. InnoDB and MyRocks (RocksDB with MySQL) are definitely not to supplement each other, They actually compliment well with respective advantages, Let me quickly explain how InnoDB and MyRocks can benefit you when used wisely, Again this blog post is not to show who (InnoDB or MyRocks) is better ? We regularly benchmark both of these storage engines before recommending to our customers on what is best suited for their database infrastructure operations ? so we would like to share our thoughts on this post.

How InnoDB and MyRocks are different ?

• MyRocks supports only READ-COMMITTED isolation level, There is no REPEATABLE-READ isolation level like InnoDB so no gap locking like InnoDB, We have written detailed blog on InnoDB transaction isolation levels …

Percona announces the GA release of Percona Server for MySQL 5.7.22-22 on on May 31, 2018. Download the latest version from the Percona web site or the Percona Software Repositories. You can also run Docker containers from the images in the Docker Hub repository.

Based on MySQL 5.7.22, including all the bug fixes in it, Percona Server for MySQL 5.7.22-22 is the current GA release in the Percona Server for MySQL 5.7 series. Percona …

The schema changes in production can cause lock at time and makes the slave to lag. It is more tedious and troublesome with PXC ( Galera ) cluster which can be made smoother with Percona online schema change.

Image Courtesy : Photo by Andrew Ruiz on Unsplash

We have seen with most of the consulting projects where the customer might be having a dedicated DB (MySQL) server ,but running with a default configuration, without any optimisation for underlying hardware, “An idle hardware is similar to idle money will give you no returns”.

Well again if you are from a non-DBA background and you have chosen InnoDB as your engine of choice. The next question will be, what are the major variable that needs to be tuned for the available hardware? here is the answer for you

In this post, We are going to detail about the variable innodb_dedicated_server in MySQL 8.0.11. This variable solves our above …