(depesz) In previous post in the series I wrote about how to interpret single line in explain analyze output, it’s structure, and later on described all basic data-getting operations (nodes in explain tree).

To find duplicate records you can use GROUP BY and count on the attributes which you want to check for duplicates and use HAVING to select all records with a count greater then one:

(morgan tocker) In my previous post, I wrote about when data gets loaded in and out of cache. The goal of caching is to avoid having to perform disk IO, which if we are talking about hard drives, each operation is about 20 million times slower than CPUs or about 100 thousand times slower than memory

(Rohit Kalhans) MySQL replication slave features a powerful capability of ignoring conflicts like duplicate key error, key not found errors etc. while applying row events. This is exceptionally useful while doing row based replication(RBR) from the master when the slave already contains some data

(Andrew Dunstan) As we get more experience in using JSON in Postgres we get a better idea of what we need to make its use simple and effective. This work is the result of some such experience.

(Rob Gravelle) Ease of use and speedy performance are just two of the many features that make MySQL one of the most popular databases in use today. Unfortunately, a high adoption rate makes MySQL a target for many malicious individuals and organizations.

(Ike Walker) A few days ago I was doing some cleanup on a passive master database using the MySQL client. I didn’t want my commands to be replicated so I executed set sql_log_bin=0 in my session.

(Joel Jacobson) I cannot count the number of times I’ve written the same stupid code, just to do something as simple as making sure the UPDATE updates exactly one row.

(Jeremy Cole) This afternoon, Arjen Lentz and I were discussing InnoDB’s behavior without a declared PRIMARY KEY, and the topic felt interesting enough and undocumented enough to warrant its own short post.

(morgan tocker) A cold cache, or a poorly tuned cache can be responsible for a number of performance problems. If we look at the data and indexes of InnoDB, the cache responsible is called the InnoDB buffer pool.