This is mainly a cheat sheet for me to remember. Nothing rocket science. It often makes sense to use netcat/nc to copy MySQL database between hosts in trusted networks. It bypasses encryption overhead of SSH and depending on configuration can be significantly faster. Also note MySQL should be down when you copy data unless you’re […]
Read MoreYesterday, I (Zardosht) posted an entry introducing clustering indexes. Here, I elaborate on three differences between a clustering index and a covering index: Clustering indexes can create indexes that would otherwise bounce up against the limits on the maximum length and maximum number of columns in a MySQL index. Clustering indexes simplify syntax making them […]
Read MoreIn this posting I’ll describe TokuDB’s multiple clustering index feature. In general (not just for TokuDB) a clustered index or a clustering index is an index that stores the all of the data for the rows. Quoting the MySQL 5.1 reference manual: Accessing a row through the clustered index is fast because the row data […]
Read MoreThe TokuDB storage engine for MySQL employs Fractal Tree technology. We’ve been planning to write a white paper explaining how fractal tree indexing works, but haven’t gotten to it yet. In the mean time, here are links to some academic papers that relate to our technology. Cache-Oblivious B-Trees by Michael A. Bender, Erik D. Demaine […]
Read MoreI find it very interesting how Sun does not get the very basic principle of true community Open Source development – you’ve got to give up on making a big splash. Traditional close source company often develop product in the secret and when it comes out as a surprise for computers and making a big […]
Read MoreEvery so often I run into situation when I need to kill a lot of connections on MySQL server – for example hundreds of instances of some bad query is running making server unusable. Many people have special scripts which can take the user, source host or query as a parameter and perform the action. […]
Read MoreWe announce next version of our xtrabackup tool and we consider it stable enough to put label RC on it. Changelist includes: – use O_DIRECT by default for handling InnoDB files – use posix fadvise call to disable OS caching of copying files – disable recovery of double buffer Also we added binary builds for […]
Read MoreUsing xtrabackup for copying files can really saturate your disks, and that why we made special option
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--throttle=rate |
to limit rate of IO per second. But it really works when you do local copy. What about stream backup ? Even you copy just to remote box with
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innobackupex --stream=tar | ssh remotebox "tar xfi -" |
, read may be so intensive so […]
Read MoreI should say I can see results of new engineering/refactoring/bug hunt efforts inside Sun/MySQL. Over last couple of weeks I started getting a lot of messages from the bugs system about bugs I reported long ago which were deferred to be fixed later or were left in open state. Here is example of such a […]
Read MoreSometimes when you do profiling you can see number like this in timestamps. Periodically in our patches there was Query_time: 18446744073709550.000 in slow.log file (well, it was fixed recently, but still appears in other places). I faced this problem several years ago when only 2-core AMD Opteron systems appeared and I noticed sysbench getting crazy […]
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