On Fri, 2006-03-10 at 15:17 +0100, mylists@stripped wrote:
> UPDATE `tbl_temp` set attribute = 'xyz' where attribute <> 'xyz' LIMIT
> 5000;
>
> is not faster then running update tbl_temp set attribute = 'xyz' ... it
> runs SLOWER, about 5minutes or so...
if attribute is unindexed, then it's going to do a full table scan
looking for non matching rows. without condition pushdown enabled, it's
going to do this in the mysql server, passing things over the wire.
> and my error if i run truncate:
is...?
> also if i just run a delete i come into trouble:
yes, due to max operations in a transaction.
> p.s. i think the setup explained in the documentation is good but who
> uses databases just keeping 80MB inside?... i think it could be better
> to see real life values like having servers with 4gb ram or more and
> keeping more then one database in it and more then just 10 tables with
> about 10 attributes in them ;) ...
but such a setup is realistic to run on a single machine when testing
cluster. I know I don't buy machines with less than 2GB of RAM these
days - but laptop companies still ship some with only 512MB. So to help
people learn about how things work, we don't use all their memory :)
> my troubles came from migrating MyISAM tables into our cluster... there
> is no faq about such ? or i don't found any... also where i could tweak
> performance if i want more is not explained....
A bunch of options are talked about in the manual, but it does require
knowledge to tweak these properly. there's some info in the docs, some
more explanation in the list archives and us developers and the
consultants know a lot more too.
> and at least - is there any tool to see processes in my cluster and see
> what server is doing what? or to create databases or or or... -.-
what do you want to see?
What ndbd is doing? They can be doing a lot of things at once.
--
Stewart Smith, Software Engineer
MySQL AB, www.mysql.com
Office: +14082136540 Ext: 6616
VoIP: 6616@stripped
Mobile: +61 4 3 8844 332
Jumpstart your cluster:
http://www.mysql.com/consulting/packaged/cluster.html
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