I know this problem, you can fix it as follows:

1. Check if there are really 1,000 connections on MySQL, and exclude whether the connection is leaked
2. Because changing any connection pool parameters will create a new connection pool, it is likely that it has nothing to do with the number of connections.
3. In summary, it is likely to be timeout. Increase the timeout time and observe it. https://doris.apache.org/docs/lakehouse/database/jdbc