10,000 transactions per day should not be a problem for MySql.
1) Make sure you put an index on the key search field. This will increase
performance more than anything else.
2) Performance can be enhance by tuning server parameters
See Docs .
3) The new release of MySql 5.0 has a performance feature called
"Stored Procedures". This lets you pre-compile your MySql query
so MySql does not have to compile the same query over and over
again.
As this is my first posting of GFY, please forgive any glaring errors.
Kind regards,
Bill