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Showing entries 1 to 10 of 54 10 Older Entries

Displaying posts with tag: mysql performance (reset)

Mo’ Data, Mo’ Problems
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Welcome to blog #2 in a series about the benefits of the Fractal Tree. In this post, I’ll be explaining Big Data, why it poses such a problem and how Tokutek can help. Given the fact that I am a lifelong fan of both Hip-hop and Big Data, the title was a no-brainer and, given the artist, a bit of a pun.

 I am as tired as you of hearing the term “Big Data.” It’s so overused, that it ceases to have specific meaning anymore. You see, data hardly ever starts as “big” or a “problem.” Rather, it starts small and easily manageable, but gradually grows to some unimaginable size and becomes a beast in need of slaying, like …

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Tracking MySQL query history in long running transactions
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Long running transactions can be problematic for OLTP workloads, particularly where we would expect most to be completed in less than a second. In some cases a transaction staying open just a few seconds can cause behaviour that is entirely unexpected, with the developers at a loss as to why a transaction remained open. There are a number of ways to find long running transactions, luckily versions of MySQL from 5.6 onwards provide some very insightful instrumentation.

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Looking deeper into InnoDB’s problem with many row versions
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A few days ago I wrote about MySQL performance implications of InnoDB isolation modes and I touched briefly upon the bizarre performance regression I found with InnoDB handling a large amount of versions for a single row. Today I wanted to look a bit deeper into the problem, which I also filed as a bug.

First I validated in which conditions the problem happens. It seems to happen only in REPEATABLE-READ isolation mode and only …

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What is stuck in MySQL server?
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There are few easy ticks to see what is stuck inside MySQL instance. All these techniques will not give you whole picture, but might help to find queries that block performance. Let’s start from what exactly doing your MySQL server right now.

Which queries are running now?

This will give you an idea what’s running right now so you can find long running queries which slowing down MySQL and/or causing replication lag:

mysql -e "SHOW PROCESSLIST" | grep -v -i "sleep"

It is more convenient than just run “SHOW PROCESSLIST” as it’s hiding all connected threads in “Sleep” state so you’ll get a clean output. Also you can get …

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Full table scans and MySQL performance
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High season is coming, how do you make sure that MySQL will handle the increased load? Stress tests could help with that, but it’s not a good idea to run them in a production environment. In this case Select_scan, Select_full_join and other MySQL counters could quickly give you an idea of how many queries are not performing well and could cause a performance degradation as the load goes up.

Select_scan from SHOW GLOBAL STATUS indicates how many full table scans were done since last MySQL restart. Scanning the entire table is a resource intensive operation. It also forces MySQL to store unnecessary data in the buffer pool, wasting memory and IO …

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MySQL’s INNODB_METRICS table: How much is the overhead?
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Starting with MySQL 5.6 there is an INNODB_METRICS table available in INFORMATION_SCHEMA which contains some additional information than provided in the SHOW GLOBAL STATUS output – yet might be more lightweight than PERFORMANCE_SCHEMA.

Too bad INNODB_METRICS was designed during the Oracle-Sun split under MySQL leadership and so it covers only InnoDB counters. I think this would be a great replacement to all counters that are currently provided though SHOW STATUS – it captures more information such as providing MIN/MAX counts for …

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“How to monitor MySQL performance” with Percona Cloud Tools: June 25 webinar
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We recently released a new version of Percona Cloud Tools with MySQL monitoring capabilities. Join me June 25 and learn the details about all of the great new features inside Percona Cloud Tools – which is now free in beta. The webinar is titled “Monitoring All (Yes, All!) MySQL Metrics with Percona Cloud Tools” and begins at 10 a.m. Pacific time.

In addition to MySQL metrics, Percona Cloud Tools also monitors OS performance-related stats. The new …

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Abdel-Mawla Gharieb: Impact of General Query Log on MySQL Performance
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Sometimes, it is required to enable the general query log (which is disabled by default). If the general query log is enabled the server writes to this log information when clients connect or disconnect, and each SQL statement received from the client.

The question is, does enabling the general query log affects the MySQL performance ?
Also, it is possible to record the output of this log into either file or table in the mysql database (mysql.general_log), what is the performance impact of each one?

Let's do some simple benchmark for those scenarios to measure the actual impact on the mysql performance.

System Information:

HW configurations:


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Optimizing MySQL Performance: Choosing the Right Tool for the Job
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Next Wednesday, I will present a webinar about MySQL performance profiling tools that every MySQL DBA should know.

Application performance is a key aspect of ensuring a good experience for your end users. But finding and fixing performance bottlenecks is difficult in the complex systems that define today’s web applications. Having a method and knowing how to use the tools available can significantly reduce the amount of time between problems manifesting and fixes being deployed.

In the webinar, titled “Optimizing MySQL Performance: Choosing the Right Tool for the Job,” we’ll start with the …

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This Week in Website Performance
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This Week in Website Performance is a weekly feature of the Monitis.com blog. It summarizes recent articles about website performance. How to make yourweb site better, how to improve your users experience when they come to your website and how to optimize the overall experience. Why? Because your friends at Monitis.com care.

Improving website performance – 10 tips

Author: palepurple.

Discussed in this short …

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Showing entries 1 to 10 of 54 10 Older Entries

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