Replication is the process that transfers data from an active master to a slave server, which reproduces the data stream to achieve, as best as possible, a faithful copy of the data in the master.

To check replication health, you may start with sampling the service, i.e. committing some Sentinel value in the master and retrieving it from the slave.

Sentinel data: Tap tap… Is this thing on?
If you want to make sure that replication is working, the easiest test is using replication itself to see if data is being copied across from the master to the slaves. The method is easy:

1. Make sure that the data you want to see is NOT in the master or in the slave. If you skip this step, you may think that replication is working, while in fact it may not.
2. Either create a table …

Both MySQL and MariaDB have been busy, each introducing new features, sometimes creating the same feature, often with different syntax.

This is sometimes good for users, who have a wide choice. And sometimes it is bad, as once you are used to the deployment and syntax of one flavor, it is hard to switch to a different one. This problem is enhanced if you are dealing with an application, MySQL Sandbox, that needs to work well with all flavors.

The latest releases of MySQL Sandbox (3.0.51 to 3.0.55) have been necessary to solve minor and major troublesome points with MySQL 5.7.8 and MariaDB 10.1.

The current version (3.0.55) can install all the newest releases, including replication with MySQL 5.7.8 which suffers from a compatibility bug (better explored in a separate article). …

As part of the release of MySQL-5.7.7, based on community feedback, improvements have been made with respect to replication defaults, which will make MySQL replication safer and easier to use.

This blog is intended to provide information about these default changes, and it briefly explains the advantages of having them.

1) Enable Simplified GTID recovery by default:

binlog_gtid_simple_recovery=TRUE by default.
https://dev.mysql.com/doc/refman/5.7/en/replication-options-gtids.html#sysvar_binlog_gtid_simple_recovery

This variable controls how binary log files are iterated during the search for GTIDs when MySQL starts or restarts.

Setting this option to TRUE gives improved recovery performance. Because of this option server startup and binary log purge …

Slave election is a popular HA architecture,  first MySQL MariaDB toolkit to manage switchover and failover in a correct way was introduce by Yoshinori Matsunobu into MHA.

Failover and switchover in asynchronous clusters require caution:

- The CAP theorem need to be satisfy. Getting strong consistency, require the slave election to reject transactions ending up in the old master when electing the candidate master.

- Slave election need to take care that all events on the old master are applied to the candidate master before switching roles.

- Should be instrumented to found a good candidate master and make sure it's setup to take the master role.

- Need topology detection, a master role can't be pre defined, as the role …

Heterogenous replication involves moving data from one database platform to another. This is a complicated endevour because datatypes, date & time formats, and a whole lot more tend to differ across platforms. In fact it’s so complex many enterprises simply employ a commercial solution to take away the drudgery. Join 31,000 others and follow Sean … Continue reading Replicate MySQL to Amazon Redshift with Tungsten: The good, the bad & the ugly →

One of the cool new features in 5.7 Release Candidate is Multi Source Replication, as I previously looked into in 5.7.5 DMR.

I’ve had more and more people like the idea of this, so here’s a quick set-up as to what’s needed and how it could work.

1. Prepare master environments.
2. Prepare 40 masters for replication.
3. Create slave.
4. Insert data into the Masters.

* I originally tried running 50 mysql’s but I just ran out of resources on my old pc, so it’s at 40.

* The real key behind this scenario is that each of the masters has a unique centre_code that is implicitly inserted via the app & users at that site. i.e. no other site will want to modify any data that was entered from that site, e.g. call centre reclaims dept for specific areas / regions, CNC …

MySQL replication isn’t perfect and sometimes our data gets out of sync, either by a failure in replication or human intervention. We are all familiar with Percona Toolkit’s pt-table-checksum and pt-table-sync to help us check and fix data inconsistencies – but imagine the following scenario where we mix regular replication with the Tungsten Replicator:

We have regular replication going from master (db1) to 4 slaves (db2, db3, db4 and db5), but also we find that db3 is also master of db4 and db5 using Tungsten replication for 1 database called test. This setup is currently working this way because it was deployed some time ago when multi-source replication was not possible using regular MySQL replication. This is now a working feature in …

The link to the slides of my talks can be found at the end of this post but first, let me share some thoughts about PLMCE.

Talking with people, I was surprised to be criticized of presenting only the good sides of my solution without giving credit to the good side of the alternative solutions.  More than surprised, I was also a little shocked as I want to be perceived as objective as possible.  Let me try to fix that:

• I am not a GTID and log-slaves detractor, I am a simplicity lover.
• I actually like GTIDs and I have some use-cases for them; one of  them is described in the MariaDB Knowledge Base (search for last_gtid in that page).
• But I think that using GTIDs in the slave protocol is complex and that a …

Version: 5.5.5-10.0.10-MariaDB-log MariaDB Server

When I use mariadb as multi-source slave DB I met a strange problem . Creating index on a vary large partition table , Mariadb do — copy to tmp table on the slave side. It takes a long time and still not finish over 9 hours.

Primary : MySQL 5.6.16 —

add index on a partition table:

CREATE TABLE `track_raw_wap211_log` (
 `table_id` varchar(100) DEFAULT NULL,
 `page_id` varchar(100) DEFAULT NULL,
 `banner_id` varchar(100) DEFAULT NULL,
 `button_id` varchar(100) DEFAULT NULL,
 `test_id` varchar(100) DEFAULT NULL,
 `classfication` varchar(100) DEFAULT NULL,
 `request_refer` varchar(100) DEFAULT NULL,
 `request_url` text,
 `title` varchar(100) DEFAULT NULL,
 `user_id` varchar(100) DEFAULT NULL,
 `language` varchar(100) DEFAULT NULL,
 `event` varchar(100) DEFAULT NULL,
 `event_desc` varchar(100) DEFAULT NULL,
 `event_type` varchar(100) DEFAULT NULL,
 `log_version` varchar(100) DEFAULT …

Updated 2015-04-25: add the link to the slides of my PLMCE talk and a link to a bug number.

MaxScale 1.1.0 is out and includes the new Binlog Server module.  This is the first post in s series of three.  The two others are about Operations and High Availability.  The links to the 2 other posts are at the end of this page.

In this post, I present how to install and configure MaxScale as a Binlog