In this blog post, I’ll provide an explanation why you should avoid using the CREATE TABLE AS SELECT statement.

The SQL statement “create table <table_name> as select …” is used to create a normal or temporary table and materialize the result of the select. Some applications use this construct to create a copy of the table. This is one statement that will do all the work, so you do not need to create a table structure or use another statement to copy the structure.

At the same time there are a number of problems with this statement:

1. You don’t create indexes for the new table
2. You are mixing transactional and non-transactional statements in one transaction. As with any DDL, it will commit current and unfinished transactions
3. CREATE TABLE … SELECT …

In this post, we’ll look at updating and deleting rows with ClickHouse. It’s the first of two parts.

Update: Part 2 of this post is here.

ClickHouse is fast – blazing fast! It’s quite easy to pick up, and with ProxySQL integrating with existing applications already using MySQL, it’s way less complex than using other analytics options. However, ClickHouse does not support UPDATE/DELETE (yet). That entry barrier can easily dissuade potential users despite the good things I mentioned.

If there is a will, there is a way! We have so far taken advantage of the new feature that supports more granular partitioning strategy (by week, by day or something else). With more …

There are 3 pillars for a database architecture: Monitoring, Backup / Restore process, High Availability This blog post is about database High Availability; more precisely about one of the best combo of the moment : MySQL 5.7 Group Replication : the only native HA solution for MySQL, it's a Single/Multi-master update everywhere replication plugin for MySQL with built-in automatic distributed recovery, conflict detection and group membership. ProxySQL 1.4 : probably the best proxy for MySQL.

Not long ago we had an internal discussion about security and how to enforce a stricter set of rules to prevent malicious acts, and block other undesired queries.

ProxySQL comes up as a possible tool that could help us in achieving what we were looking for. Last year I had written how to use ProxySQL to stop a single query.

That approach may be good for few queries and as temporary solution. But what can we do when we really want to use ProxySQL as an SQL-based firewall? And more importantly, how to do it right?

First of all, let us define what “right” can be in this context.

For right I mean an approach that will allow us to have rules matching as specific as possible, and impacting the production system as least as possible.

To make this clearer, …

Update: I included the results for when PCID is disabled, for comparison, as a worse case scenario.

After learning about Meltdown and Spectre, I waited patiently to get a fix from my OS vendor. However, there were several reports of performance impact due to the kernel mitigation- for example on the PostgresQL developers mailing list there was reports of up to 23% throughput loss; Red Hat engineers report a regression range of 1-20%, but setting OLTP systems as the worse type of workload. As it will be highly dependent on the hardware and workload, I decided of doing some test myself for the …

In my MySQL Parallel Replication session at Percona Live Santa Clara 2017, I talked about a bug in Write Set tracking for parallel replication (Bug#86078).  At the time, I did not fully understand what was going wrong but since then, we (Engineers at Oracle and me) understood what happened and the bug is supposed to be fixed in MySQL 8.0.4.  This journey thought me interesting MySQL behavior and

tl;dr: Try it out here: https://preetam.github.io/explain-analyzer/#!/explain/

I introduced my explain analyzer for MySQL a little over a month ago. Here’s what I wrote at the end of that post:

It could look a lot better. The real thing isn’t as nice as the design, and the design is still pretty bad. I’ll work on that soon. In terms of the implementation, the explain analyzer is a single page app without any state, so if you refresh the page, you’ll lose everything. I think I’m going to add a “share” feature so that you can get a permalink with all of the values saved. That’ll take some more work but I think it would be a neat opportunity to use AWS Lambda for a user-facing site!

Both the design and the sharing feature have been addressed with …

tl;dr: Try it out here: https://preetam.github.io/explain-analyzer/#!/explain/

I introduced my explain analyzer for MySQL a little over a month ago. Here’s what I wrote at the end of that post:

It could look a lot better. The real thing isn’t as nice as the design, and the design is still pretty bad. I’ll work on that soon. In terms of the implementation, the explain analyzer is a single page app without any state, so if you refresh the page, you’ll lose everything. I think I’m going to add a “share” feature so that you can get a permalink with all of the values saved. That’ll take some more work but I think it would be a neat opportunity to use AWS Lambda for a user-facing site!

Both the design and the sharing feature have been addressed …

Galera Cluster’s automatic node provisioning simplifies the complexity of scaling out a database cluster with guaranteed data consistency. SST and IST improve the usability of initial data synchronization without the need to manually backup the database and copy it to the new node. Combine this with Galera's ability to tolerate different network setups (e.g, WAN replication), we can now migrate the database between different isolated networks with zero service disruption.

In this blog post, we are going to look into how to migrate our MySQL Galera Cluster without downtime. We will move the database from Amazon Web Service (AWS) EC2 to Google Cloud Platform (GCP) Compute Engine, with the help of a relay node. Note that we had a similar blog post in the past, but this one uses a different approach.

The …

Percona announces the release of Percona Monitoring and Management 1.5.3. This release contains fixes for bugs found after the release of Percona Monitoring and Management 1.5.2, as well as some important fixes and improvements not related to the previous release.

Improvements

• PMM-1874: The read timeout of the proxy server (/prometheus) has been increased from the default of 60 seconds to avoid nxginx gateway timeout error when loading data-rich dashboards.
• PMM-1863: We improved our handling of temporary Grafana credentials

Bug fixes

• …