TWCS Parameters - min max trreshold

[Lucas Benevides <lu...@maurobenevides.com.br>]

Hello community,

I am testing the Time Window Compaction Strategy (TWCS), in Cassandra 3.11
version with 10 nodes. The documentation (
https://docs.datastax.com/en/cassandra/3.0/cassandra/operations/opsConfigureCompaction.html)
says it has only two parameters that are related to the same configuration:
the size of the Time Window.

However I tried to set the other two parameters: min_threshold and
max_threshold and it works. In the Alex Dejanovski post (
http://thelastpickle.com/blog/2016/12/08/TWCS-part1.html) he says that in
the first compaction, the TWCS uses the parameters of STCS.

Does TWCS uses only these two parameters of STCS (min and max threshold) or
 uses all the STSC parameters?

Lucas Benevides
Brasilia, Brazil.

Re: TWCS Parameters - min max trreshold

[Jeff Jirsa <jj...@gmail.com>]

TWCS will pass through all of the options to STCS, and use them for the
TWCS first window ("now").

It will also use min_threshold to determine whether or not to try to invoke
STCS in the current ("now") bucket, and max_threshold to determine how many
sstables it will combine per pass in older buckets

On Mon, Aug 14, 2017 at 7:43 AM, Lucas Benevides <
lucas@maurobenevides.com.br> wrote:

> Hello community,
>
> I am testing the Time Window Compaction Strategy (TWCS), in Cassandra 3.11
> version with 10 nodes. The documentation (https://docs.datastax.com/en/
> cassandra/3.0/cassandra/operations/opsConfigureCompaction.html) says it
> has only two parameters that are related to the same configuration: the
> size of the Time Window.
>
> However I tried to set the other two parameters: min_threshold and
> max_threshold and it works. In the Alex Dejanovski post (
> http://thelastpickle.com/blog/2016/12/08/TWCS-part1.html) he says that in
> the first compaction, the TWCS uses the parameters of STCS.
>
> Does TWCS uses only these two parameters of STCS (min and max threshold)
> or  uses all the STSC parameters?
>
> Lucas Benevides
> Brasilia, Brazil.
>