We are using Scala, Akka and JDBC to insert data in the database, we have around 25M insert to do which are basically lines from 5000 files. We issue a DELETE according to the file (mandatory) and then a COPY each 1000 lines of that file.
DELETE request : DELETE FROM table WHERE field1 = ? AND field2 = ?;
COPY request : COPY table FROM STDIN WITH CSV
We have indexes on our database that we can't delete to insert our data.
When we insert the data there is some kind of freezes on the databases between requests. Freezes occur about every 20 seconds.