Have a use case wherein need to maintain a connection open to a database open to execute queries periodically.
Is it advisable to close connection after executing the query and then reopen it after the period interval (10 minutes). I would guess no since opening a connection to database is expensive.
Is connection pooling the alternative and keep using the connections?
You should use connection pooling. Write your application code to request a connection from the pool, use the connection, then return the connection back to the pool. This keeps your code clean. Then you rely on the pool implementation to determine the most efficient way to manage the connections (for example, keeping them open vs closing them).
Generally it is ‘expensive’ to open a connection, typically due to the overhead of setting up a TCP/IP connection, authentication, etc. However, it can also be expensive to keep a connection open ‘too long’, because the database (probably) has reserved resources (like memory) for use by the connection. So keeping a connection open can tie-up those resources.
You don’t want to pollute your application code managing these types of efficiency trade-offs, so use a connection pool.