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From Apache Wiki <wikidi...@apache.org>
Subject [Cassandra Wiki] Update of "FAQ" by TylerHobbs
Date Sat, 20 Oct 2012 20:48:48 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Cassandra Wiki" for change notification.

The "FAQ" page has been changed by TylerHobbs:
http://wiki.apache.org/cassandra/FAQ?action=diff&rev1=154&rev2=155

Comment:
gc_grace is now in the schema, not schema.xml

  <<Anchor(i_deleted_what_gives)>>
  
  == I delete data from Cassandra, but disk usage stays the same. What gives? ==
- Data you write to Cassandra gets persisted to SSTables. Since SSTables are immutable, the
data can't actually be removed when you perform a delete, instead, a marker (also called a
"tombstone") is written to indicate the value's new status. Never fear though, on the first
compaction that occurs after ''GCGraceSeconds'' (hint: storage-conf.xml) have expired, the
data will be expunged completely and the corresponding disk space recovered. See DistributedDeletes
for more detail.
+ Data you write to Cassandra gets persisted to SSTables. Since SSTables are immutable, the
data can't actually be removed when you perform a delete, instead, a marker (also called a
"tombstone") is written to indicate the value's new status. Never fear though, on the first
compaction that occurs after `gc_grace_seconds` (configurable per-column family as part of
the schema) have passed, the data will be expunged completely and the corresponding disk space
recovered. See DistributedDeletes for more detail.
  
  <<Anchor(cloned)>>
  

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