DataGrip using too much memory when exporting to file

I've been backuping old tables of about 10 million rows and 1 gb in size without any problem. But suddenly DataGrip started to freeze at about 500k rows, saying it doesn't have enough memory. I increased heap from 750 MB to 10 GB and the problem persists, even though at higher sizes. What I've noticed is that memory won't clear unless I restart the program. 

I've tried rebuilding cache, repairing IDE, unistalling and installing again, both stable and EAP versions and I still get the problem. A memory analysis show that the process that uses most memory is java.time.format