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From Lerh Chuan Low <>
Subject Re: TWCS enabling tombstone compaction
Date Mon, 12 Mar 2018 21:46:40 GMT
Dear Lucas,

Those properties that result in the log message you are seeing are
properties common to all compaction strategies. See http://cassandra.apache.
org/doc/latest/operating/compaction.html#common-options. They are
*and *tombstone_threshold*. If you didn't define them when you created your
table, then you will see the log message. I'm not fully certain what the
intent is, but in a TWCS setting you should only rely on TTLs and not run
checks for including SSTables with dropping tombstones (so it may save a
little bit of computation there). DTCS has the same property, which you can
find detail in this JIRA https://issues.apache.

You shouldn't be seeing it all the time though unless you are constantly
creating and dropping tables. Hope this helps in some way :)

On 10 March 2018 at 04:38, Lucas Benevides <>

> Dear community,
> I have been using TWCS in my lab, with TTL'd data.
> In the debug log there is always the sentence:
> " Disabling tombstone compactions for
> TWCS". Indeed, the line is always repeated.
> What does it actually mean? If my data gets expired, the TWCS is already
> working and purging the SSTables that become expired. It surely sound
> strange to me to disable tombstone compaction.
> In the subcompaction subproperties there are only two subproperties,
> compaction_window_unit and compaction_window_size. Jeff already told us
> that the STCS properties also apply to TWCS, although it is not in the
> documentation.
> Thanks in advance,
> Lucas Benevides Dias

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