Sometime we may face the problem of huge database size even after all product is deleted.
Run the following code in the sql,
TRUNCATE dataflow_batch_export; TRUNCATE dataflow_batch_import; TRUNCATE log_customer; TRUNCATE log_quote; TRUNCATE log_summary; TRUNCATE log_summary_type; TRUNCATE log_url; TRUNCATE log_url_info; TRUNCATE log_visitor; TRUNCATE log_visitor_info; TRUNCATE log_visitor_online; TRUNCATE report_viewed_product_index; TRUNCATE report_compared_product_index; TRUNCATE report_event; TRUNCATE index_event;
Sometime we may get error so try to run code one by one. And enable cache for folder only not for database during installation.
Source : http://www.tipsaid.com/reduce-magento-database-size/