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From Jon Haddad <jonathan.had...@gmail.com>
Subject Re: manual deletes with TWCS
Date Fri, 05 May 2017 20:57:04 GMT
You cannot.

From Alex’s TLP post: http://thelastpickle.com/blog/2016/12/08/TWCS-part1.html <http://thelastpickle.com/blog/2016/12/08/TWCS-part1.html>

TWCS is no fit for workload that perform deletes on non TTLed data. Consider that SSTables
from different time windows will never be compacted together, so data inserted on day 1 and
deleted on day 2 will have the tombstone and the shadowed cells living in different time windows.
Unless a major compaction is performed (which shouldn’t), and while the deletion will seem
effective when running queries, space will never be reclaimed on disk.
Deletes can be performed on TTLed data if needed, but the partition will then exist in different
time windows, which will postpone actual deletion from disk until both time windows fully
expire.


> On May 5, 2017, at 1:54 PM, John Sanda <john.sanda@gmail.com> wrote:
> 
> How problematic is it to perform deletes when using TWCS? I am currently using TWCS and
have some new use cases for performing deletes. So far I have avoided performing deletes,
but I am wondering what issues I might run into.
> 
> 
> - John


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