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Re: TWCS - Disabling Tombstone Compactions for TWCS


Hi Eric,

I think it has something to do with the same reason it is disabled in DTCS:
https://issues.apache.org/jira/browse/CASSANDRA-9234 can shed more light.



On 5 June 2018 at 09:02, Eric Stevens <mightye@xxxxxxxxx> wrote:

> I'm trying to understand the reasoning behind this stanza in Time Windowed
> Compaction Strategy's init:
> https://github.com/apache/cassandra/blob/cassandra-3.0.
> 15/src/java/org/apache/cassandra/db/compaction/
> TimeWindowCompactionStrategy.java#L63-L69
>
> Reposted (and slightly reformatted) here for convenience:
> if (
>
> !options.containsKey(AbstractCompactionStrategy.
> TOMBSTONE_COMPACTION_INTERVAL_OPTION)
> &&
>
> !options.containsKey(AbstractCompactionStrategy.
> TOMBSTONE_THRESHOLD_OPTION)
> )
> {
>     disableTombstoneCompactions = true;
>     logger.debug("Disabling tombstone compactions for TWCS");
> }
> else
>     logger.debug("Enabling tombstone compactions for TWCS");
>
> If you have left both tombstone compaction interval, and tombstone
> threshold at default values, you are *opting out* of tombstone compactions?
>
> This was certainly a surprising side effect to us, as we expected unset
> values to have the same exact effect as setting those values to their
> defaults.
>
> I'm wondering if someone can shed some more light on this, or if this
> should be considered a bug (it seems really intentional).
>