Many times I get new customers that say they want/need "mysql cluster"
but what they really mean is they need master/slave. One recent customer
was adamant about doing cluster and I told him "throwing your app at
cluster does not guarantee improvement. Your app must be designed for
cluster." Customer came back with "What's an example of an app designed
for cluster?" I don't really have a solid answer for him.
Can anyone offer suggestions/comments on that? He's running an all PHP
web-app. Is it the queries that make an app 'cluster-worthy'? I'm
doing some simple tests using sysbench, comparing MyISAM, InnoDB and NDB
using a simple "SELECT a FROM foo WHERE pk_column = X" and MyISAM and
InnoDB are trumping NDB by a huge margin. I would expect a query on pk
to be fastest on NDB.