Hi,
I'm trying to use the time-to-live functionality, which I've patched
into Cassandra 0.6.6. My problem is that my sstables are not emptying.
When my data expires, they do reduce in size, but only by a fraction of
what I expected. I've come to realise that this must be because I've set
the TTL on my Columns, but actually, I need the SuperColumns to expire
too - I believe that my sstables remain large because I (probably) have
a lot of empty SuperColumns. Unfortunately, I can't see a way to set a
TTL on a SuperColumn.
Does anyone have any suggestions for what I can do here?
Actually, I've also just been playing with a few tests of "manually"
deleting a SuperColumn, rather than using TTL - i.e. using Hector's
Deletion with setSuper_column. Whilst this appears to work as far as
making the data unavailable to the client is concerned, it only appears
to reduce sstable size by about three quarters. This is in the case
where I know that the sstable contains only my test inserts, which I
have completely deleted. Why doesn't the sstable reduce in size to
(almost) nothing?
Thanks,
Andy.
--
Andy Burgess
Principal Development Engineer
Application Delivery
WorldPay Ltd.
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