49 lines
2.2 KiB
Plaintext
49 lines
2.2 KiB
Plaintext
== What is mydumper? Why? ==
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* Parallelism (hence, speed) and performance (avoids expensive character set conversion routines, efficient code overall)
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* Easier to manage output (separate files for tables, dump metadata, etc, easy to view/parse data)
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* Consistency - maintains snapshot across all threads, provides accurate master and slave log positions, etc
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* Manageability - supports PCRE for specifying database and tables inclusions and exclusions
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== How to build it? ==
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Run:
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cmake .
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make
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One needs to install development versions of required libaries (MySQL, GLib, ZLib, PCRE):
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NOTE: you must use the correspondent mysql devel package.
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* Ubuntu or Debian: apt-get install libglib2.0-dev libmysqlclient15-dev zlib1g-dev libpcre3-dev libssl-dev
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* Fedora, RedHat and CentOS: yum install glib2-devel mysql-devel zlib-devel pcre-devel openssl-devel
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* openSUSE: zypper install glib2-devel libmysqlclient-devel pcre-devel zlib-devel
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* MacOSX: port install glib2 mysql5 pcre pkgconfig cmake
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(You may want to run 'port select mysql mysql5' afterwards)
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One has to make sure, that pkg-config, mysql_config, pcre-config are all in $PATH
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Binlog dump is disabled by default to compile with it you need to add -DWITH_BINLOG=ON to cmake options
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== How does consistent snapshot work? ==
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This is all done following best MySQL practices and traditions:
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* As a precaution, slow running queries on the server either abort the dump, or get killed
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* Global write lock is acquired ("FLUSH TABLES WITH READ LOCK")
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* Various metadata is read ("SHOW SLAVE STATUS","SHOW MASTER STATUS")
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* Other threads connect and establish snapshots ("START TRANSACTION WITH CONSISTENT SNAPSHOT")
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** On pre-4.1.8 it creates dummy InnoDB table, and reads from it.
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* Once all worker threads announce the snapshot establishment, master executes "UNLOCK TABLES" and starts queueing jobs.
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This for now does not provide consistent snapshots for non-transactional engines - support for that is expected in 0.2 :)
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== How to exclude (or include) databases? ==
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Once can use --regex functionality, for example not to dump mysql and test databases:
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mydumper --regex '^(?!(mysql|test))'
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Of course, regex functionality can be used to describe pretty much any list of tables.
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