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10 Newer Entries Showing entries 91 to 100 of 373 10 Older Entries

Displaying posts with tag: Insight for DBAs (reset)

Innodb redo log archiving
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Percona Server 5.6.11-60.3 introduces a new “log archiving” feature. Percona XtraBackup 2.1.5 supports “apply archived logs.” What does it mean and how it can be used?

Percona products propose three kinds of incremental backups. The first is full scan of data files and comparison the data with backup data to find some delta. This approach provides a history of changes and saves disk space by storing only data deltas. But the disadvantage …

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7 Key MySQL clustering technologies – A joint webinar with 451 Research
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I’m looking forward to Wednesday’s joint webinar on MySQL clustering technologies with Matt Aslett, research director of data management and analytics over at 451 Research. We’ll be participating in a live, in-depth discussion of MySQL Clustering for High Availability and Scalability.

Matt will present an overview of the trends driving …

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How to log slow queries on Slave in MySQL 5.0 with pt-query-digest
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Working as a Percona Support Engineer, every day we are seeing lots of issues related to MySQL replication. One very common issue is slave lagging. There are many reasons for slave lag but one common reason is that queries are taking more time on slave then master. How to check and log those long-running queries?  From MySQL 5.1, log-slow-slave-statements variable was introduced, which you can …

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Tools and tips for analysis of MySQL’s Slow Query Log
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MySQL has a nice feature, slow query log, which allows you to log all queries that exceed a predefined about of time to execute. Peter Zaitsev first wrote about this back in 2006 – there have been a few other posts here on the MySQL Performance Blog since then (check …

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Open Source Appreciation Day at the Percona Live MySQL Conference
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I am very pleased to announce a new event in conjunction with the Percona Live MySQL Conference and Expo this year: Open Source Appreciation Day on Monday, March 31st in the Santa Clara Convention Center! We are pleased to announce two separate groups holding events this year under this new umbrella. We are hosting an event called “ …

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Introducing backup locks in Percona Server
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TL;DR version: The backup locks feature introduced in Percona Server 5.6.16-64.0 is a lightweight alternative to FLUSH TABLES WITH READ LOCK and can be used to take both physical and logical backups with less downtime on busy servers. To employ the feature with mysqldump, use mysqldump --lock-for-backup --single-transaction. The next release of Percona XtraBackup will also be using backup locks automatically if the target server supports the feature.

Now on to the gory details, but let’s start with some history.

In the beginning…

In the beginning there was …



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Many-table joins in MySQL 5.6
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I recently worked on an uncommon slow query: less than 100 rows were read and returned, the whole dataset was fitting in memory but the query took several seconds to run. Long story short: the query was a join involving 21 tables, running on MySQL 5.1. But by default MySQL 5.1 is not good at handling joins with such a large number of tables. The good news is that MySQL 5.6 brings welcome improvements.

Isolating the problem

As always with a slow query, finding the execution plan with EXPLAIN is the 1st step to understand where time is spent. Here the plan was very good with almost all joins using the primary key or a unique …

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Oracle’s Mats Kindahl to weave MySQL Fabric into Percona Live session
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Mats Kindahl of Oracle is lead developer of MySQL Fabric

MySQL Fabric is an integrated framework for managing farms of MySQL servers with support for both high-availability and sharding. Its development has been spearheaded by Mats Kindahl, senior principal software developer in MySQL at Oracle.

Mats is leading the MySQL Scaling and High-Availability effort covering the newly released MySQL Fabric and the MySQL Applier for Hadoop. He is also the architect and implementer of several features (mostly replication features), including the row-based replication available in 5.1 and the binary log group …

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How rows_sent can be more than rows_examined?
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When looking at queries that are candidates for optimization I often recommend that people look at rows_sent and rows_examined values as available in the slow query log (as well as some other places). If rows_examined is by far larger than rows_sent, say 100 larger, then the query is a great candidate for optimization. Optimization could be as simple as adding a few indexes or much more complicated as in generating summary tables so you do not need to rely on large aggregations for your real-time queries.

Just to be clear this is a great rule for your “real time” queries need to be handled very quickly and in …

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DBA 101: Sometimes forgotten functionality in the MySQL client
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The MySQL client has some functionalities some of us never use. Why would you use them and what is the added value of this?

Every DBA and developer has had a moment when he or she needs to connect to a MySQL database using the command line tool. Therefore I’ve written down an explanation of some command line commands you can insert in the CLI, most of them give added value and make your experience with the cli more enjoyable.

prompt

Who has never witnessed the scary feeling of not being connected to the write database when having several terminals open. I do, due to the fact I use …

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10 Newer Entries Showing entries 91 to 100 of 373 10 Older Entries

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