(Szymon Guz) PostgreSQL has got the great feature named “functional indexes”. A normal index just stores sorted values of some field. It is great for searching, as the values are already sorted.

(Mike Benshoof) Recently, I was working with a client that asked about using Percona Xtrabackup to take a snapshot of a particular MySQL schema and then reload it with a different schema name on the same server.

(morgan tocker) In an earlier post, I wrote about when MySQL loads data in and out of cache. At the end of this post, I talked about the concept of page churn, and having enough memory for your working set:

(Justin Swanhart) Shard-Query inserts data into a “coordinator” table when answering queries. When there is a GROUP BY on the original query, the coordinator table contains a UNIQUE KEY over the GROUP BY attributes. Shard-Query uses INSERT .. ON DUPLICATE KEY UPDATE in combination with bulk inse

(Stephane Combaudon) The main benefit of using GTIDs is to have much easier failover than with file-based replication. We will see how to change the replication topology when using GTID-based replication. That will show where GTIDs shine and where improvements are expected.

(Jervin R) MySQL can optimize aggregate functions like MIN and MAX as long as the columns specified are indexed. This means that, in the case of MIN and MAX, the optimizer should be able to identify the highest and lowest values of an indexed column from the B-Tree index,

(morgan tocker) thought I would take the new subquery optimizations in MySQL 5.6 for a spin today, using the world sample database provided by MySQL for certification and training.

(Giuseppe Maxia) As you probably know, Tungsten Replicator can replicate data from MySQL to MongoDB. The installation is relatively simple and, once done, replication works very well. There was a bug in the installation procedure recently, and as I was testing that the breakage has been fixed, I wan

(Daniël van Eeden) As far as I know there isn’t a well accepted set of best practices for MySQL, but there are many best practices known and used by most MySQL DBA’s. One of those best practices is that the datadir must not be equal to a mountpoint; it has to be a subdirectory of a mountpoint.

(Ian Barwick) A while back I posted some SQL which helps track of changes to the PostgreSQL settings file. I’ve found it useful when benchmarking tests with different settings, but unfortunately the pg_settings_log() function needs to be run manually after each setting change.