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Showing entries 1 to 10 of 15 5 Older Entries

Displaying posts with tag: pt-query-digest (reset)

How much could you benefit from MySQL 5.6 parallel replication?
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I have heard this question quite often: “At busy times, our replicas start lagging quite frequently. We are using N schemas, so which performance boost could we expect from MySQL 5.6 parallel replication?” Here is a quick way to give you a rough estimate of the potential benefit.

General idea

In MySQL 5.6, parallelism is added at the schema level. So in theory, if you have N schemas and if you use N parallel threads, replication could be up to N times faster. This assumes at least 2 things:

  • Replication throughput scales linearly with the number of parallel threads.
  • Writes are …
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Measuring the impact of tcpdump on Very Busy Hosts
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A few years back Deva wrote about how to use tcpdump on very busy hosts. That post sparked my interest about exploring how to measure the impact of tcpdump on very busy hosts. In this post, I wanted to highlight how much of an impact there really is and what options you have to make the query collection much more effective.

Some things you need to know:

  • The test is a sysbench read-only workload, 8 tables, 8 threads, 1000000 rows each with 16G of buffer pool. Dataset fully in memory.
  • sysbench …
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Calling all MySQL DBAs: How do you use Percona Toolkit?
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Percona Toolkit is one of our most mature open source applications. Derived from Maatkit and Aspersa, Percona Toolkit has evolved significantly over the years. The software now contains 32 tools, over 4,000 tests, and has been downloaded over 250,000 times. Anyone who manages a database – from DBAs to system administrators to even software developers – benefits from Percona Toolkit’s ability to perform a variety of MySQL server and system tasks that are too difficult …

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Percona Toolkit 2.2.11 for MySQL is now available
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Percona is pleased to announce the availability of Percona Toolkit 2.2.11.  Released on Sept. 25, Percona Toolkit is a collection of advanced command-line tools to perform a variety of MySQL server and system tasks that are too difficult or complex for DBAs to perform manually. Percona Toolkit, like all Percona software, is free and open source.

This release contains bug fixes for …

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Howto automate MySQL slow query analysis with amazon RDS
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If you’ve used relational databases for more than ten minutes, I hope you’ve heard of slow queries. Those are those pesky little gremlins that are slowing down your startup, and preventing scalability you so desperately need. Luckily there’s a solution. What I’ve found is if I send a report to developers every week, it keeps […]

Capturing MySQL Data with tcpdump
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Percona Toolkit has a great tool, pt-query-digest, that can use tcpdump data. Capturing raw tcp data can be taxing on a server, however, when you see the following message:

64000 packets received by filter
12000 packets dropped by kernel

When there is a significant amount of user cpu% being used, the kernel will drop packets you are trying to capture, leading to a partial picture and missing data. I’ve found that if you write it using the native tcpdump format, it’s more …

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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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Analyzing WordPress MySQL queries with Query Analytics
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This blog, MySQLPerformanceBlog.com, is powered by WordPress, but we never really looked into what kind of queries to MySQL are used by WordPress. So for couple months we ran a Query Analytics (part of Percona Cloud Tools) agent there, and now it is interesting to take a look on queries. Query Analytics uses reports produced by pt-query-digest, but it is quite different as it allows to see trends and dynamics of particular query, in contrast to pt-query-digest, which is just one static report.

Why looking into queries important? I gave …

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Percona Toolkit 2.2.3 released; bug fixes include pt-online-schema-change
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Among all of the excellent events going on like YAPCVelocity, and Percona MySQL University, we recently released Percona Toolkit 2.2.3. It’s a small update that includes the following:

  • pt-online-schema-change did not handle the failure of the DROP TRIGGER statements correctly
  • Created …
  [Read more...]
Showing entries 1 to 10 of 15 5 Older Entries

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