W dniu 27.02.2013 10:57, Marco Matarazzo pisze:> You may also be
interested in this:
>
> https://issues.apache.org/jira/browse/CASSANDRA-3783
CASSANDRA-3783 might not be the case here. The question is about using
null in SELECT statements, which will require modifications in secondary
indexes code, which is unlikely to be done now/soon (see Sylvain's
comments in CASSANDRA-3783 and CASSANDRA-5081) and probably will be left
to a follow-up ticket, while CASSANDRA-3783 will focus on INSERT/UPDATE
statements (which would be very usefull together with prepared
statements [CASSANDRA-5081]).
M.
Also, I *guess* that a deleted column takes some (very small?) space with its
tombstone, until it's removed. But I leave the details to someone else, as I'm
definitely not an expert.
Il giorno 27/feb/2013, alle ore 10:35, Alain RODRIGUEZ <arodr...@gmail.com> ha
scritto:
Cassandra (C*) has no NULL values. C* is column schemaless, meaning you can
have different columns on each row of the same ColumnFamily (CF).
So if you want to check if a certain column is NULL for a row, you just check
if it exist. By the way, you can store a column with a name and no value (empty
value). This empty value doesn't take any disk space AFAIK.
About the TTL, their point is precisely to keep them for a predefined time. C*
delete them on without any action needed by a client, it's an internal work.
Alain
2013/2/27 Sloot, Hans-Peter <hans-peter.sl...@atos.net>
Hi,
How does Cassandra handle NULL values?
I want to know how I can see rows where a certain column has no values.
For example if I set the TTL for columns is it possible to select rows where
the ttl has expired for deletion.
Regards Hans-Peter
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