cannot close connection

[ys588281]

I need to close connection after using apollo-cassandra.
Is there API provided from apollo or any other ways to close connection.
If I did not close it, I would encounter emfile error after using it for a while.
The error message is like:
Error: All host(s) tried for query failed. First host tried, 10.XXX.XXX.XX:0000: Error: connect EMFILE.

I can deal with it by increasing the limit of open files on linux server but I don't think it is a good way.

Is there anyone can help me solve this question?