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Tag Archives: io
Stonebraker trapped in Stonebraker 'fate worse than death'
Oh well, I know I shouldn’t poke directly at people, but they deserve that sometimes (at least in my very personal opinion). Heck, I even gave 12h window for this not to be hot-headed opinion. Those who followed MySQL at … Continue reading
InnoDB locking makes me sad
Vadim and others have pointed at the index->lock problems before, but I think they didn’t good job enough at pointing out how bad it can get (the actual problematic was hidden somewhere as some odd edge case). What ‘index lock’ … Continue reading
Logs memory pressure
Warning, this may be kernel version specific, albeit this kernel is used by many database systems Lately I’ve been working on getting more memory used by InnoDB buffer pool – besides obvious things like InnoDB memory tax there were seemingly … Continue reading
on performance stalls
We quite often say, that benchmark performance is usually different from real world performance – so performance engineering usually has to cover both – benchmarks allow to understand sustained performance bottlenecks, and real world analysis usually concentrates on something what … Continue reading
Read ahead…
Mark wrote about how to find situations where InnoDB read-ahead is a bottleneck. What he didn’t disclose, though, is his trick to disable read-ahead without restart or recompile of MySQL. See, there’s no internal “disable read ahead knob”. But there … Continue reading
On file system benchmarks
I see this benchmark being quoted in multiple places, and there I see stuff like: When carrying out more database benchmarking, but this time with PostgreSQL, XFS and Btrfs were too slow to even complete this test, even when it … Continue reading
Posted in mysql
Tagged benchmarks, io, performance, rant, xfs
Linux 2.6.29
2.6.29 was released. I don’t usually write about linux kernel releases, thats what Slashdot is for :), but this one introduces write barriers in LVM, as well as ext4 with write barriers enabled by default. If you run this kernel … Continue reading
iostat -x
My favorite Linux tool in DB work is ‘iostat -x’ (and I really really want to see whenever I’m doing any kind of performance analysis), yet I had to learn its limitations and properties. For example, I took 1s snapshot … Continue reading
ZFS and MySQL … not yet
Today I attended kick-ass ZFS talk (3 hours of incredibly detailed material presented by someone who knows the stuff and knows how to talk) at CEC (Sun internal training event/conference), so now I know way more about ZFS than I … Continue reading
On SSDs, rotations and I/O
Every time anyone mentions SSDs, I have a feeling of futility and being useless in near future. I have spent way too much time to work around limitations of rotational media, and understand the implications of whole vertical data stack … Continue reading
