July 23, 2014

Faster Point In Time Recovery with LVM2 Snaphots and Binary Logs

LVM snapshots is one powerful way of taking a consistent backup of your MySQL databases – but did you know that you can now restore directly from a snapshot (and binary logs for point in time recovery) in case of that ‘Oops’ moment? Let me show you quickly how. This howto assumes that you already […]

How to recover deleted rows from an InnoDB Tablespace

In my previous post I explained how it could be possible to recover, on some specific cases, a single table from a full backup in order to save time and make the recovery process more straightforward. Now the scenario is worse because we don’t have a backup or the backup restore process doesn’t work. How […]

Identifying the load with the help of pt-query-digest and Percona Server

Overview Profiling, analyzing and then fixing queries is likely the most oft-repeated part of a job of a DBA and one that keeps evolving, as new features are added to the application new queries pop up that need to be analyzed and fixed. And there are not too many tools out there that can make […]

Global Transaction ID and other patches available!

I do not know if you noticed it, but Google (Mark Callaghan, Justin Tolmer and their internal mysql-team) made a great contribution to MySQL. Patches global transaction IDs, binlog event checksums and crash-safe replication state are separated and published on Launchpad (https://code.launchpad.net/~jtolmer/mysql-server/global-trx-ids). For me it was a big wall in using these patches that they […]

Compression for InnoDB backup

Playing with last version of xtrabackup and compress it I noticed that gzip is unacceptable slow for both compression and decompression operations. Actually Peter wrote about it some time ago, but I wanted to review that data having some new information. In current multi-core word the compression utility should utilize several CPU to speedup operation, […]

Making replication a bit more reliable

Running MySQL slave is quite common and regular task which we do every day, taking backups from slave is often recommended solution. However the current state of MySQL replication makes restoring slave a bit tricky (if possible at all). The main problem is that InnoDB transaction state and replication state are not synchronized. If we […]

More patches

After some pause we are going to announce bunch of patches we made and ported for last period. Ported patches (ported from Google V2 patch): – innodb_fsync_source.patch – Show information about callers of fsync, more info – innodb_io_tune.patch – Port of two patches InnodbIOTune and InnodbAsync, more info – innodb_extra_status.patch – Show more information about […]

Mirrored Binlogs patch

Google patches V1 contain interesting patch to mirror binary log on slave. Although Google is preparing GlobalTransactionId patch, which going to be replacement for MirroredBinlogs, we still think mirroring binary logs is very useful for: Backup of binary logs in real time High availability, to switch master load to slave with mirrored binary logs By […]

Improved InnoDB rw_lock patch

There is patch from Google to improve SMP performance , but for some workloads it showed for us reverse scalability. E.g. update_key benchmark from sysbench. There are also results with Yasufumi’s rw_locks (http://bugs.mysql.com/bug.php?id=26442)

The tool I’ve been waiting for years

I’ve just been pointed to the nice tool which I was waiting for years to see. It is fincore – little perl script which allows you to see what pages of file are cached in OS memory. This is really cool.