Anuj, there are a couple of aspects that are important -1. Cassandra will not
return data with expired TTLs even if compaction has not run2. How is 1
possible? The read path will eliminate the expired TTLs from the result3. All
tombstones (explicit delete as well as expired TTLs) hang around for some time
(gc_grace_seconds)4. Once the gc_grace_seconds (default 10 days) are over the
compaction will cleanup the tombstones in SSTables that are considered for
compaction
Thanks,Nirmallya
On Monday, 21 March 2016 5:49 PM, Anuj Wadehra <anujw_2...@yahoo.co.in>
wrote:
Hi,
I want to understand how Expiring columns work in Cassandra.
Query:Documentation says that once TTL of a column expires, tombstones are
created/ marked when the sstable gets compacted. Is there a possibility that a
query (range scan/ row query) returns expired column data just because the
sstable never participated in a compaction after TTL of the column expired?
For Example: 10 AM Data inserted with ttl=60 seconds 10:05 AM A query is run
on inserted data 10:07 AM sstable is compacted and column is marked
tombstone.
Will the query return expired data in above scenario? If yes/no, why?
ThanksAnuj
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