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Displaying posts with tag: Peter Zaitsev (reset)

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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Impressions from MongoDB Day London 2014
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I visited MongoDB Day in London on November 6. Here are a few observations:

App-Developer Centric. It is interesting to see how much MongoDB is about developers; the ops side is something which is a necessary evil developers have to deal with. The ops topics covered in principle that there are no topics about choices of operating systems or hardware for MongoDB beyond flash and more memory.

Development Stacks. Being application centric there was good coverage of the MongoDB-powered …

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Innodb transaction history often hides dangerous ‘debt’
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In many write-intensive workloads Innodb/XtraDB storage engines you may see hidden and dangerous “debt” being accumulated – unpurged transaction “history” which if not kept in check over time will cause serve performance regression or will take all free space and cause an outage. Let’s talk about where it comes from and what can you do to avoid running into the trouble.

Technical Background: InnoDB is an MVCC engine which means it keeps multiple versions of the rows in the database, and when rows are deleted or updated they are not immediately removed from the database but kept for some time – …

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MySQL compression: Compressed and Uncompressed data size
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MySQL has information_schema.tables that contain information such as “data_length” or “avg_row_length.” Documentation on this table however is quite poor, making an assumption that those fields are self explanatory – they are not when it comes to tables that employ compression. And this is where inconsistency is born. Lets take a look at the same table containing some highly compressible data using different storage engines that support MySQL compression:

TokuDB:

mysql> select * from …
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Examining the TokuDB MySQL storage engine file structure
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As we know different storage engines in MySQL have different file structures. Every table in MySQL 5.6 must have a .frm file in the database directory matching the table name. But where the rest of the data resides depends on the storage engine.

For MyISAM we have .MYI and .MYD files in the database directory (unless special settings are in place); for InnoDB we might have data stored in the single table space (typically ibdata1 in the database directory) or as file per table (or better said file per partition) producing a single file with …

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Inaugural Meet-up Oklahoma City MySQL Meetup
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The inaugural Meet-up Oklahoma City MySQL Meetup is Wednesday, July 23, 2014!
As a special guest speaker, Peter Zaitsev (CEO of Percona and co-author of High Performance MySQL) will be giving a presentation on “Best Indexing Practices”, followed by a Q/A session.

Please RSVP if you plan to attend so we can get a good headcount for food and beverages that will be provided and as always, please spread the word to friends or colleagues in the industry.

It should be a great night and great first …


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Architecture and Design of MySQL-powered applications: June 11 Webinar
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The architecture of MySQL-powered applications is one of my favorite topics to talk about. It’s a very important topic because if you do not get the architecture right then you’re very likely to fail with your project – either from the standpoint of failing with performance, high availability or security requirements… or failing to deliver on time and at the planned cost.

It’s also a great topic because there is so much knowledge available these days about MySQL-powered applications. MySQL has been around for a rather long time compared with many other solutions – and now we know what …

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Do not trust vmstat IOwait numbers
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I’ve been running a benchmark today on my old test box with conventional hard drives (no raid with BBU) and noticed something unusual in the CPU utilization statistics being reported.

The benchmark was run like this:

sysbench --num-threads=64 --max-requests=0 --max-time=600000 --report-interval=10 --test=oltp --db-driver=mysql --oltp-dist-type=special  --oltp-table-size=1000000   --mysql-user=root --mysql-password=password  run

Which means: create 64 threads and hammer the database with queries as quickly as possible. As the test was run on the localhost I would expect the benchmark to completely saturate the system – being …

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How MySQL ‘queries’ and ‘questions’ are measured
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MySQL has status variables “questions” and “queries” which are rather close but also a bit different, making it confusing for many people. The manual describing it might not be very easy to understand:

Queries
The number of statements executed by the server. This variable includes statements executed within stored programs, unlike the Questions variable. It does not count COM_PING or COM_STATISTICS commands.
 Questions
The number of statements executed by the server. This includes only statements sent to the …
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Percona University @Montevideo, FISL & São Paulo MySQL Meetup
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Peter Zaitsev at last year’s Percona University event in Montevideo

Later this week I’m excited to depart on a trip to South America. First I will stop in Montevideo, Uruguay, to meet with Percona’s team out there as well as to participate in our next Percona University event on April 29.

For those who do not know, Percona University events …

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Showing entries 1 to 10 of 39 10 Older Entries

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