Re: Difference in used space: MyISAM vs ndbcluster.

[Mikael Ronström]

Hi,
MySQL Cluster uses fixed size rows in 4.1 and 5.0 (varsized implemented in 5.1). This means
that VARCHAR fields grow compared to MyISAM.

Rgrds Mikael


Anton Aleksandrov wrote:
> Hi,
> I have problem with migrating from myISAM to
> ndbcluster. MyISAM shows that database (including
> indexes) takes about 3906Mb. With idea that
> database will grow we bought 8 boxes with 2Gb of
> RAM on each. In config I have these values:
>
>
> NoOfReplicas=2
> DataMemory=1750MB
> IndexMemory=200Mb
> MaxNoOfAttributes=15000
> MaxNoOfOrderedIndexes=15000
> MaxNoOfUniqueHashIndexes=10000
> MaxNoOfConcurrentOperations=100000
> RedoBuffer=64Mb
> TimeBetweenLocalCheckpoints=13
> NoOfFragmentLogFiles=150
>
> After importing data to cluster almost all this
> space is used, "all dump 1000" says:
> Data usage is 97%(54776 32K pages of total 56000)
>
> My simple calculations give me such thing:
> (54776 * 32) / 1024 / 1024 = 1.67Gb. That's the
> state on each node. I have 8 boxes and 2 replicas
> - so it will (1.67 * 8) / 2 = 6.68Gb. So my
> database running as MyISAM grew almost double?
> Neither me, neither my boss expect such results.
>
> My question is simple - is it normal or not? Do I
> have something wrong in my config or
> calculations?
>
> Any ideas/suggestions are very kindly and warmly
> welcomed!

Mikael Ronstrom
Senior Software Architect, MySQL AB
My blog: http://mikaelronstrom.blogspot.com