One of our clients contacted us saying that his Magento database is bloated and he experienced some problems with hoster. As this kind of problem might meet anyone here is a piece of advice that can help.
If the store has been running for a certain amount of time you may check the size of log tables and delete older data or truncate the table. Here is the list of log tables:
log_customer
log_quote
log_summary
log_summary_type
log_url
log_url_info
log_visitor
log_visitor_info
Another thing you should check is the size of dataflow_batch_import and dataflow_batch_export tables of your Magento database. Their size may achieve couple of GBs.
If the import or export was not completed successfully batch data would not be deleted so you should truncate those tables if they have big size.
In most cases those actions will save you couple of hundreds of MBs.