On dbx 3, simple dbx query like "select 1 from dual" takes about 6 seconds to run. Reading search.log, I found that the time between following two event took about 1 second. And it the call was repeated 4 times for one query execution like above.
question:
12-13-2018 14:59:02.477 ERROR ChunkedExternProcessor - stderr: 14:59:02.438 14048@W1835906 [main] WARN com.splunk.dbx.message.MessageEnum - action=initialize_resource_bundle_files error=Can't find bundle for base name Messages, locale en_US
12-13-2018 14:59:03.497 ERROR ChunkedExternProcessor - stderr: 14:59:03.094 14048@W1835906 [main] INFO c.s.d.s.driver.DriverServiceImpl - action=register_driver driver=oracle.jdbc.OracleDriver 12.2 succeeded