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Showing entries 1 to 10 of 94 10 Older Entries

Displaying posts with tag: myisam (reset)

Today is the day in which MyISAM is no longer needed
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Of course, this is just a catchy title. As far as I know not all system tables can be converted to InnoDB yet (e.g. grant tables), which makes the header technically false. MyISAM is a very simple engine, and that has some inherent advantages (no transactional overhead, easier to “edit” manually, usually less space footprint on disk), but also some very ugly disadvantages: not crash safe, no foreign keys, only full-table locks, consistency problems, bugs in for large tables,… The 5.7.5 “Milestone 15″ release, presented today at the Oracle Open World has

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More then 1000 columns – get transactional with TokuDB
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Recently I encountered a specific situation in which a customer was forced to stay with the MyISAM engine due to a legacy application using tables with over 1000 columns. Unfortunately InnoDB has a limit at this point. I did not expect to hear this argument for MyISAM. It is usually about full text search or spatial indexes functionality that were missing in InnoDB, and which were introduced in MySQL 5.6 and 5.7, respectively, to let people forget about MyISAM. In this case though, InnoDB still could not be used, so I gave the TokuDB a

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Some current MySQL Architecture writings
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So, I’ve been looking around for a while (and a few times now) for any good resources that cover a bunch of MySQL architecture and technical details aimed towards the technically proficient but not MySQL literate audience. I haven’t really found anything. I mean, there’s the (huge and very detailed) MySQL manual, there’s the MySQL Internals manual (which is sometimes only 10 years out of date) and there’s various blog entries around the place. So I thought I’d write something explaining roughly how it all fits together and what it does to your system (processes, threads, IO etc).(Basically, I’ve found myself explaining this enough times in the past few years that I should really write it down and just point people to my blog).

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Which Compression Tool Should I Use for my Database Backups? (Part I: Compression)
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This week we are talking about size, which is a subject that should matter to any system administrator in charge of the backup system of any project, and in particular database backups.

I sometimes get questions about what should be the best compression tool to apply during a particular backup system: gzip? bzip2? any other?

The testing environment

In order to test several formats and tools, I created a .csv file (comma-separated values) that was 3,700,635,579 bytes in size by transforming a recent dump of all the OpenStreetMap nodes of the European portion of Spain. It had a total of 46,741,126 rows and looked like this:

171773  38.6048402      -0.0489871      4       2012-08-25 00:37:46     12850816        472193  rubensd
171774
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The MySQL ARCHIVE storage engine – Alternatives
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In my previous post I pointed out that the existing ARCHIVE storage engine in MySQL may not be the one that will satisfy your needs when it comes to effectively storing large and/or old data. But are there any good alternatives? As the primary purpose of this engine is to store rarely accessed data in disk space efficient way, I will focus here on data compression abilities rather then on performance.

The InnoDB engine provides compressed row format, but is it’s efficiency even close to the one from that available in archive engine? You can also compress MyISAM tables by using myisampack tool, but that also means a table will be read only after such operation.

Moreover, I don’t trust MyISAM nor Archive when it comes to data

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Comparing MongoDB, MySQL, and TokuMX Data Layout
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A lot is said about the differences in the data between MySQL (http://www.mysql.com/) and MongoDB. Things such as “MongoDB is document based”, “MySQL is relational”, “InnoDB has a clustering key”, etc.. Some may wonder how TokuDB, our MySQL storage engine, and TokuMX, our MongoDB product, fit in with these data layouts. I could not find anything describing the differences with a simple google search, so I figured I’d write a post explaining how things compare.

So who are the players here? With MySQL, users are likely familiar with two storage engines: MyISAM, the original default up until MySQL 5.5, and

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MariaDB Storage Engine for CCM forum
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CCM Benchmark is one of the leading forum provider on the web,  ROI is a major concern for them  and historically MyISAM was used on the forum replication cluster.  Reason is that MyISAM gave better ROI/performance on data that is hardly electable to cache mechanism.

This post is for MySQL users at scale,  if the number of servers or datacenter cost is not an issue for you, better get some more memory or flash storage and ou will found Lucifer server to demonstrate that your investment is not a lost of money or just migrate to Mongo.  

Quoting Damien Mangin, CTO at CCM "I like my data to be small, who want's to get to a post where the question is not popular and have no answer. Despite cleaning we still get more data than what commodity hardware memory can offer and storing all post in memory would be a major waste of



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MySQL and the SSB – Part 2 – MyISAM vs InnoDB low concurrency
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This blog post is part two in what is now a continuing series on the Star Schema Benchmark.

In my previous blog post I compared MySQL 5.5.30 to MySQL 5.6.10, both with default settings using only the InnoDB storage engine.  In my testing I discovered that innodb_old_blocks_time had an effect on performance of the benchmark.  There was some discussion in the comments and I promised to follow up with more SSB tests at a later date.

I also promised more low concurrency SSB tests when Peter blogged about the importance of performance at low concurrency.

The SSB
The SSB tests a

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MariaDB/MySQL: Performances of COUNT()
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Versione italiana

How fast is COUNT() execution? Well, it depends from the Storage Engine.

Try to create an Aria or MyISAM table, INSERT some data, and execute an EXPLAIN similar to the following:

MariaDB [(none)]> EXPLAIN SELECT COUNT(*) FROM test.t1;
+------+-------------+-------+------+---------------+------+--------+------+------+------------------------------+
| id   | select_type | table | type | possible_keys | key  | key_len | ref  | rows | Extra                        |
+------+-------------+-------+------+---------------+------+--------+------+------+------------------------------+
|    1 | SIMPLE      | NULL  | NULL | NULL          | NULL | NULL    | NULL | NULL |
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MySQL Triggers with Logging
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Somebody asked why you can’t implement MySQL triggers that write information when you want to stop the DML statement, like autonomous procedures in Oracle. The question was a surprise but I didn’t find anything on it, so here’s how you can do it. This is more or less like an autonomous process by leveraging both the InnoDB and MyISAM engine’s behaviors. This post leverages an earlier explanation of MySQL Triggers.

  • First you create a MyISAM table, which is a persistent store that auto commits when you’re other InnoDB tables can be transactionally dependent. Here’s a simple MyISAM logger table.
  • CREATE TABLE logger
    ( logger_id         INT UNSIGNED AUTO_INCREMENT PRIMARY KEY
    , logger_event      VARCHAR(50)
    ,
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    Showing entries 1 to 10 of 94 10 Older Entries

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