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Funniest bug ever

 | January 31, 2009 |  Posted In: Events and Announcements

Recently my attention was brought to this bug which is a nightmare bug for any consultant. Working with production systems we assume reads are reads and if we’re just reading we can’t break anything. OK may be we can crash the server with some select query which runs into some bug but not cause the […]

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Linux schedulers in tpcc like benchmark

 | January 30, 2009 |  Posted In: Benchmarks

I mentioned earlier that IO scheduler CFQ coming by default in RedHat / CentOS 5.x may be not so good for MySQL. And yesterday one customer reported that just changing cfq to noop solved their InnoDB IO problems. I ran tpcc scripts against XtraDB on our Dell PowerEdge R900 server (16 cores, 8 disks in […]

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iiBench with deletes

 | January 29, 2009 |  Posted In: Tokutek, TokuView

We modified the iiBench benchmark to perform deletions as well as insertions, and compared InnoDB to Tokutek’s Fractal TreeTM storage engine, both running on MySQL 5.1. I’ll post the revised iiBench tarball soon. Here is what the performance looks like: The iiBench-with-deletions benchmark works as follows. The benchmark employs a fact table with an autoincremented […]

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The perils of InnoDB with Debian and startup scripts

 | January 28, 2009 |  Posted In: Insight for DBAs

Are you running MySQL on Debian or Ubuntu with InnoDB? You might want to disable /etc/mysql/debian-start. When you run /etc/init.d/mysql start it runs this script, which runs mysqlcheck, which can destroy performance. It can happen on a server with MyISAM tables, if there are enough tables, but it is far worse on InnoDB. There are […]

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Another scalability fix in XtraDB

 | January 23, 2009 |  Posted In: Benchmarks, Percona Software

Recent scalability fixes in InnoDB and also Google’s and your SMP fixes almost made InnoDB results acceptable in primary key lookups queries, but secondary indexes were forgotten for some time. Now having Dell PowerEdge R900 on board (16CPU cores, 16GB RAM) I have some time for experiments, and I played with queries

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iiBench Fractal Tree Results

 | January 23, 2009 |  Posted In: Tokutek, TokuView

A few weeks ago I reported InnoDB performance on the iiBench 1-billion row insert test. Today I’m reporting on Tokutek’s Fractal TreeTM storage engine performance. We ran iiBench on the same hardware (Sun x4150, 8 cores @ 3.16GHz, 16GB memory, 6 SAS disk HW RAID 0) using Tokutek’s storage engine for MySQL. The performance looks […]

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5.0.75-build12 Percona binaries

 | January 23, 2009 |  Posted In: Percona Software

After several important fixes to our patches we made binaries for build12. Fixes include: Control of InnoDB insert buffer to address problems Peter mentioned, also check Bug 41811 to see symptoms of problem with Insert buffer. * innodb_flush_neighbor_pages (default 1) – When the dirty page are flushed (written to datafile), this parameter determines […]

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Beware: ext3 and sync-binlog do not play well together

 | January 21, 2009 |  Posted In: Hardware and Storage

One of our customers reported strange problem with MySQL having extremely poor performance when sync-binlog=1 is enabled, even though the system with RAID and BBU were expected to have much better performance. The problem could be repeated with SysBench as follows:

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