Re: TWCS enabling tombstone compaction

[Lerh Chuan Low]

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
*tombstone_compaction_interval
*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.
org/jira/browse/CASSANDRA-9234.

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 
wrote:

> Dear community,
>
> I have been using TWCS in my lab, with TTL'd data.
> In the debug log there is always the sentence:
> "TimeWindowCompactionStrategy.java:65 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
>

TWCS enabling tombstone compaction

[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:
"TimeWindowCompactionStrategy.java:65 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