At a recent optimizer webinar, I talked about MySQL introducing a new style for hints, and that MySQL 5.7 also added support for more hints, see Sergey Glukhov’s blog. A question I got at the end of the webinar was what to do with the hints in the application code after an upgrade?…

For the past few years I’ve been writing and speaking about time-series storage, a problem inspired by what I help build at VividCortex and also my personal projects. I’ve been thinking about a related problem for much longer, but I haven’t had to work on it until now: ranking.

At VividCortex, we have a new tool called the Profiler. It allows you to rank within various categories of metrics, like MySQL or OS metrics, by a dimension, like count. You can rank top processes by total CPU time or memory, MySQL queries by execution time, and so on. We can do this for arbitrary time ranges.

The ranking is performed on the sums of values within each time range. If we’re ranking by CPU usage during a 300 second window, we look at the CPU usage measurements for each process at every second, sum those values up, …

Time for another entry in the EXPLAIN FORMAT=JSON is cool! series of blog posts. This time we’ll discuss how using EXPLAIN FORMAT=JSON allows you to see that

cost_info

  knows why the optimizer prefers one index to another.

Tables often have more than one index. Any of these indexes can be used to resolve query. The optimizer has to make a choice in this case. One of the metrics that can be used to help make the choice is the potential cost of the query evaluation.

For example, let’s take the table

titles

  from the standard employees database:

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Finally, the book will give you a thorough overview of how data can be augmented and annotated to make it easier to glean the golden nuggets of knowledge you seek while wading through your sensor data. …

Hi Akileish,
If you replicate from Oracle to Oracle ,as example, and enable DDL replication, it will create the same logical structure on the target . Essentially the GoldenGate will replay the command to create the index applying the mapping. Of course the internal index structure like number of levels and leaf blocks may be different. Speaking about other database engines it will depend from supported operations for the replication. As example if you replicate from Oracle to MySQL all DDL it is not going to work since DDL replication is not supported for that configuration.

—
Gleb

In our previous post, we described how MySQL Master-HA (MHA) performs a so called slave promotion (also known as master failover) and ensures all remaining slaves in the topology get attached under the new master and become equal in data set.

Another failover solution is the MariaDB MaxScale proxy in combination with the MariaDB Replication Manager. Let’s look at how these two separate products can work together and perform a failover. We will also describe how you can use them.

MaxScale + MariaDB Replication Manager MaxScale

For those unfamiliar with MaxScale: MaxScale is a versatile database proxy written in C that supports not only intelligent query routing but can also function as both a binlog server and intermediate master. MaxScale consists of five plugins: Authentication, Protocol, Monitor, Routing, …

In our MySQL replication tutorial we have covered different aspects of replication including master failover by performing a slave promotion using ClusterControl. The slave promotion will turn a slave into the new master, and re-attach the remaining slaves in the topology under the new master. Keep in mind that ClusterControl will not perform an automated slave promotion in the current version. We do have a helper to find the most advanced slave (Cluster drop down: Find Most Advanced Slave) to determine the best candidate slave.

Another thing to keep in mind is that, as of time of writing, ClusterControl only supports replication topologies using MySQL GTID. You can add your existing MariaDB based replication topology to ClusterControl but promoting slaves can …

On an earlier post I wrote about real time query monitoring on MySQL with a third party tool and without one. The script is useful as it works with MySQL 5.5 and later. However, if you're using a later version of MySQL, you should look at the SYS schema. It is a collection of views, functions and procedures to help MySQL administrators get insight in to MySQL Database usage. It's available to

After nearly ten years working for MySQL, I’m pursuing a new opportunity to expand into new areas of open source data infrastructure as part of the excellent Cloudera support organization.  I’ve been fortunate to work with incredibly talented, dedicated and wonderful people on relational databases, and I’m looking forward to doing the same in the Hadoop space in my new role.  Despite this transition, I intend to remain active in the MySQL community – most immediately, finishing off a handful of half-finished blog posts in the coming weeks.

My various bit roles at MySQL have given me a front-row seat as the company grew from a smaller independent company to a prominent product at Sun to part of a much larger, enterprise-focused portfolio within Oracle.  I’m incredibly proud of the progress MySQL has made over the years, in each stage – but the past 6 years under the stewardship of Oracle are …