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Displaying posts with tag: Stéphane Combaudon (reset)

More on MySQL 5.6 multi-threaded replication and GTIDs (and Feb. 25 webinar)
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In a previous post, titled “Multi-threaded replication with MySQL 5.6: Use GTIDs,” I explained that using GTID replication is almost a requirement when using MySQL 5.6 MTS. Let’s see now how to perform the day-to-day operations when MTS and GTIDs are both enabled. (I’ll also be presenting a related webinar next week titled “Multi-threaded Replication in MySQL 5.6 and …

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Percona XtraDB Cluster 5.6: a tale of 2 GTIDs
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Say you have a cluster with 3 nodes using Percona XtraDB Cluster (PXC) 5.6 and one asynchronous replica connected to node1. If asynchronous replication is using GTIDs, moving the replica so that it is connected to node2 is trivial, right? Actually replication can easily break for reasons that may not be obvious at first sight.

Summary

Let’s assume we have the following setup with 3 PXC nodes and one asynchronous replica:

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Online GTID rollout now available in Percona Server 5.6
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Global Transaction IDs (GTIDs) are one of my favorite features of MySQL 5.6. The main limitation is that you must stop all the servers at the same time to allow GTID-replication. Not everyone can afford to take a downtime so this requirement has been a showstopper for many people. Starting with Percona Server 5.6.22-72.0 enabling GTID replication can be done without almost no downtime. Let’s see how to do it.

Implementation of the Facebook patch

Finding a solution to migrate to …

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Multi-threaded replication with MySQL 5.6: Use GTIDs!
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MySQL 5.6 allows you to execute replicated events in parallel as long as data is split across several databases. This feature is named “Multi-Threaded Slave” (MTS) and it is easy to enable by setting slave_parallel_workers to a > 1 value. However if you decide to use MTS without GTIDs, you may run into annoying issues. Let’s look at two of them.

Skipping replication errors

When replication stops with an error, a frequent approach is to “ignore now and fix later.” This means you will run SET GLOBAL sql_slave_skip_counter=1 to be able to restart replication as quickly as possible and …

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Diagnosing SST errors with Percona XtraDB Cluster for MySQL
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State Snapshot Transfer (SST) is used in Percona XtraDB Cluster (PXC) when a new node joins the cluster or to resync a failed node if Incremental State Transfer (IST) is no longer available. SST is triggered automatically but there is no magic: If it is not configured properly, it will not work and new nodes will never be able to join the cluster. Let’s have a look at a few classic issues.

Port for SST is not open

The donor and the joiner communicate on port 4444, and if the port is closed on …

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Making HAProxy 1.5 replication lag aware in MySQL
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HAProxy is frequently used as a software load balancer in the MySQL world. Peter Boros, in a past post, explained how to set it up with Percona XtraDB Cluster (PXC) so that it only sends queries to available nodes. The same approach can be used in a regular master-slaves setup to spread the read load across multiple slaves. However with MySQL replication, another factor comes into play: replication lag. In this case the approach mentioned for  …

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Faster restarts for MySQL and Percona Server 5.6.21+
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By default in MySQL 5.6, each time MySQL is started (regular start or crash recovery), it iterates through all the binlog files when GTIDs are not enabled. This can take a very long time if you have a large number of binary log files. MySQL and Percona Server 5.6.21+ have a fix with the simplified-binlog-gtid-recovery option. Let’s explore this issue.

Understanding the issue

It was first reported by Yoshinori @ Facebook (bug …

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Schema changes in MySQL for OpenStack Trove users
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People using OpenStack Trove instances can hit a common issue in the MySQL world: how to perform schema change operations while minimizing the impact on the database server? Let’s explore the options that can allow online schema changes.

Summary

With MySQL 5.5, pt-online-schema-change from Percona Toolkit is your best option for large tables while regular ALTER TABLE statements are only acceptable for small tables. Also beware of metadata locks.

With MySQL 5.6, almost all types of …

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Typical misconceptions on Galera Replication for MySQL
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Even if a Galera node looks like a regular MySQL server, the underlying replication mechanism is very different. This implies some changes in the way you have to configure the Galera nodes. Here are some of the most common misconceptions about Galera when using Percona XtraDB Cluster.

Q: Why should I enable binary logging as it is not needed by Galera replication?
Unlike for regular asynchronous MySQL replication, it is true that …

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Data inconsistencies on MySQL replicas: Beyond pt-table-checksum
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Percona Toolkit’s pt-table-checksum is a great tool to find data inconsistencies between a MySQL master and its replicas. However it is sometimes not enough to know that there are inconsistencies and let pt-table-sync fix the issue: you may want to know which exact rows are different to identify the statements that created the inconsistency. This post shows one way to achieve that goal.

The issue

Let’s assume …

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Showing entries 1 to 10 of 28 10 Older Entries

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