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10 Newer Entries Showing entries 31 to 40 of 82 10 Older Entries

Displaying posts with tag: configuration (reset)

Upgrading passwords from old_passwords to “new passwords”
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You have old_passwords=1 in your my.cnf. I’m guessing this is because you used one of the my-small.cnf, my-large.cnf etc. templates provided with your MySQL distribution.

These files can easily win the “most outdated sample configuration file contest”.

Usually it’s no big deal: if some parameter isn’t right, you just go and change it. Some variables, though, have a long-lasting effect, and are not easily reversed.

What’s the deal with old_passwords?

No one should be using these anymore. This variable makes the password …

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Web and Telco mode Cluster Configuration
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The Core Scripts (aka Configurator) for MySQL Cluster has now been updated with a new feature that allows you to tune cluster for a particular workload.
Currently there are two types of workloads supported:

  • Web
  • Telco/Realtime

The Web workload is suitable for applications:

  • with long running transactions (scans, joins and/or large updates)
  • reading …

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Cluster/J - Document-oriented approach on MySQL Cluster
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In a project Severalnines is engaged in, we are developing a realtime application based on Cluster/J. To start with, I must say cluster/j is fantastic and so far I am very happy with it and beaten our expectations big time. It is quite new however and we stumbled on a couple of issues, but those were fixed very fast by the Cluster/J developers. The bugs we encountered were:

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Custom MySQL config files to ensure maximum performance
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The config files that come with MySQL server are generally not that good. They almost never work well for enterprise server loads and will leave most people wondering why the database needs someone to come fix it. In fact that might be why they roll those configs by default, to keep the consulting services alive and profitable. Personally I have no issues with consulting services, but everyone should start out with good configs to begin with. Well, no worries… here are config files for different system RAM configurations. Just choose the one that fits how much RAM your server has and make sure the cnf file is in place before you …

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Upgrading to Barracuda & getting rid of huge ibdata1 file
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Some of this is old stuff, but more people are now converting to InnoDB plugin, so as to enjoy table compression, performance boosts. Same holds for people converting to Percona’s XtraDB. InnoDB plugin requires innodb_file_per_table. No more shared tablespace file.

So your ibdata1 file is some 150GB, and it won’t reduce. Really, it won’t reduce. You set innodb_file_per_table=1, do ALTER TABLE t ENGINE=InnoDB (optionally ROW_FORMAT=COMPRESSED KEY_BLOCK_SIZE=8), and you get all your tables in file-per-table …

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Tuning InnoDB Configuration
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I had earlier written a post on tuning the MySQL server configuration which was more geared towards the MyISAM storage engine. While that is not because I didn't intend on ignoring InnoDB but because I had planned a whole post on tuning InnoDB related configuration. So this post is the post that I had planned, I have discussed the major configuration parameters in here that should help you out most of the times.

Where’s my cnf file?
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So you have a running MySQL server, it’s working well and everyone’s happy. You want to make a minor change to the configuration file, so you edit the file, restart MySQL – but the change doesn’t catch!

Or maybe you want to check that some global variable has not been dynamically changed without an update to the configuration file. But the configuration file doesn’t make any sense — it looks like nothing is common between the file and the server.

Wait, which my.cnf file does MySQL read? Rather, which my.cnf files?

Ever happened to you? If you’re well organized, and only keep a single …

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MySQL terminology: processes, threads & connections
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There’s some confusion in the MySQL terminology for processes, threads & connections, which I will try to resolve. I can’t explain the full nature of what processes and threads are; please see Wikipedia [1] [2] for that. But here’s some basics with regard to MySQL:

  • MySQL server is a single process application.
  • It is multithreaded.
  • It (usually) acts as a TCP/IP server, accepting connections.
  • Each connection gets a dedicated …
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Tuning MySQL Server Settings
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The default configuration file for MySQL is intended not to use many resources, because its a general purpose sort of a configuration file. The default configuration does enough to have MySQL running happily with limited resources and catering to simple queries and small data-sets. The configuration file would most definitely need to be customized and tuned if you intend on using complex queries and when you have good amount of data. Most of the tunings mentioned in this post are applicable to the MyISAM storage engine, I will soon be posting tunings applicable to the Innodb storage engine. Getting started...

MMM for MySQL single reader role
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The standard documentation and tutorials on MMM for MySQL, for master-master replication setup, suggest one Virtual IP for the writer role, and two Virtual IPs for the reader role. It can be desired to only have a single virtual IP for the reader role, as explained below.

The two IPs for the reader role

A simplified excerpt from the mmm_common.conf sample configuration file, as can be found on the project’s site and which is most quoted:

<host db1>
  mode                    master
  peer …
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10 Newer Entries Showing entries 31 to 40 of 82 10 Older Entries

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