Memory leak #2
Description
I get an "FATAL ERROR: CALL_AND_RETRY_2 Allocation failed - process out of memory" error trying to migrate a mysql table to mongodb. I tried with another table and I got the same error. In the first case after about 79k rows processed, and in the second after about 140k. I mention that I have nothing fancy in the config.json - just field to field migration, no data modifiers.
If I run it with the --trace-gc flag I get "allocation failure" pretty fast.
Please fix this because it's pretty unusable if it crashes after 79k rows. I need it to work for a few dozen million rows so deleting processed rows and restarting the script is not a viable option.
PS: I run on winxp 32 bit. I tried today on win7 x64 and it stops at record 53, but not from the memory leak. I think it is a queue problem as it only queues 53 records (another table only queues 17 records):
......
queue.length = 52
queue.length = 53
and then it starts importing and stops after 53 rows.
Another thing is that I think the memory leak is related to mongo library because if I do a dry run it gets past 79k. I initially thought it is from the mysql library (I read mysqljs/mysql#471) but I updated to 2.0 alpha 7 (you used alpha 3) and I still have the same issue.