'Configuration' Tag

  • Baffling 5.7 global/status variables issues, unclean migration path

    August 7, 2015

    MySQL 5.7 introduces a change in the way we query for global variables and status variables: the INFORMATION_SCHEMA.(GLOBAL|SESSION)_(VARIABLES|STATUS) tables are now deprecated and empty. Instead, we are to use the respective performance_schema.(global|session)_(variables|status) tables. But the change goes farther than that; there is also a security change. Oracle created a pitfall of 2 changes at the same time: […]

  • TokuDB configuration variables of interest

    October 23, 2013

    During our experiments I came upon a few TokuDB variables of interest; if you are using TokuDB you might want to look into these: tokudb_analyze_time This is a boundary on the number of seconds an ANALYZE TABLE will operate on each index on each partition on a TokuDB table. That is, if tokudb_analyze_time = 5, […]

  • On MySQL plugin configuration

    October 1, 2013

    MySQL offers plugin API, with which you can add different types of plugins to the server. The API is roughly the same for all plugin types: you implement an init() function, a deinit(); you declare status variables and global variables associated with your plugin, and of course you implement the particular implementation of plugin call. […]

  • Thoughts on MySQL 5.6 new replication features

    October 15, 2012

    After playing a little bit with MySQL 5.6 (RC), and following closely on Giuseppe's MySQL 5.6 replication gotchas (and bugs), I was having some thoughts. These are shared for a few reasons: Maybe I didn't understand it well, and someone could correct me Or I understood it well, and my input could be of service […]

  • Useful sed / awk liners for MySQL

    July 6, 2011

    Listing some useful sed / awk liners to use with MySQL. I use these on occasion. sed, awk & grep have many overlapping features. Some simple tasks can be performed by either. For example, stripping empty lines can be performed by either: grep '.' awk '/./' sed '/./!d' grep -v '^$' awk '!/^$/' sed '/^$/d' […]

  • Recovering a MySQL `root` password: the fourth solution

    March 22, 2011

    Have just read Darren Cassar's Recovering a MySQL `root` password – Three solutions. There's a fourth solution: using an init-file, which leads to just one restart of the database instead of two. It also avoids the security issue involved with using skip-grant-tables. I've written all about it before on Dangers of skip-grant-tables. Darren's 1st advice […]

  • Upgrading passwords from old_passwords to "new passwords"

    February 28, 2011

    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, […]

  • Upgrading to Barracuda & getting rid of huge ibdata1 file

    February 15, 2011

    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. […]

  • Where's my cnf file?

    December 7, 2010

    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 […]

  • MySQL terminology: processes, threads & connections

    November 3, 2010

    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. […]

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