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From galantaa <alongal...@gmail.com>
Subject Too many open files on Bucketing sink
Date Tue, 13 Mar 2018 14:08:01 GMT
Hey all,
I'm using bucketing sink with a bucketer that creates partition per customer
per day.
I sink the files to s3.
it suppose to work on around 500 files at the same time (according to my

I have a critical problem of 'Too many open files'.
I've upload two taskmanagers, each with 16 slots. I've checked how many open
files (or file descriptors) exist with 'lsof | wc -l' and it had reached
over a million files on each taskmanager!

after that, I'd decreased the num of taskSlots to 8 (4 in each taskmanager),
and the concurrency dropped.
checking 'lsof | wc -l' gave around 250k file on each machine. 
I also checked how many actual files exist in my tmp dir (it works on the
files there before uploading them to s3) - around 3000.

I think that each taskSlot works with several threads (maybe 16?), and each
thread holds a fd for the actual file, and thats how the numbers get so

Is that a know problem? is there anything I can do?
by now, I filter just 10 customers and it works great, but I have to find a
real solution so I can stream all the data.
Maybe I can also work with a single task Slot per machine but I'm not sure
this is a good idea.

Thank you very much,

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