Hey @hiep95
At the moment, the only way to increase the query timeout limit is to either set up your own self hosted instance of Retool in which case you can do so with the DBCONNECTOR_QUERY_TIMEOUT_MS environment variable, or make your request directly from the browser as mentioned here.
If you're looking to get a sum across all of your data you may be able to still partition your data and sum the distinct parts, then add those values together. What kind of resource are you using?