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From Apache Wiki <wikidi...@apache.org>
Subject [Cassandra Wiki] Update of "StorageConfiguration" by JonHermes
Date Fri, 10 Sep 2010 23:13:31 GMT
Dear Wiki user,

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

The "StorageConfiguration" page has been changed by JonHermes.
http://wiki.apache.org/cassandra/StorageConfiguration?action=diff&rev1=45&rev2=46

--------------------------------------------------

  
  These are currently the same types used for validators.
  
+  * '''default_validation_class'''
+ 
+ Used in conjunction with the validation_class property in the per-column settings to guarantee
the type of a column value.
+ 
+ Default is: 'BytesType', a no-op.
+ 
   * '''gc_grace_seconds'''
  
  Time to wait before garbage-collection deletion markers.  Set this to a large enough value
that you are confident that the deletion marker will be propagated to all replicas by the
time this many seconds has elapsed, even in the face of hardware failures.  The default value
is ten days.
@@ -166, +172 @@

  
  Defaults are: '200000' keys cached, and '0', disabled row cache.
  
+  * '''min_compaction_threshold''' and '''max_compaction_threshold'''
+ 
+ Previously in the CompactionManager, these values tune the size and frequency of minor compactions.
The min and max boundaries are the number of tables to attempt to merge together at once.
Raising the minimum will make minor compactions take more memory and run less often, lowering
the maximum will have the opposite effect.
+ 
+ Note: Setting minimum and maximum to 0 will disable minor compactions. USE AT YOUR OWN PERIL!
+ 
+ Defaults are: '4' minimum tables to compact at once, and '32' maximum.
+ 
   * '''preload_row_cache'''
  
  Attempts to populate the row cache on start up with sequential reads. Despite the improvement
over random seeks during runtime, this can still take a fairly long time if the row cache
to fill is massive.
@@ -177, +191 @@

  Before 0.7, read_repair was either invoked on every read request or on none of them. This
is now tunable as a double between 0 and 1 (inclusive on both ends) for the chance of invoking
the repair.
  
  Default is: '1.0', read repair on every read request.
- 
-  * '''default_validation_class'''
- 
- Used in conjunction with the validation_class property in the per-column settings to guarantee
the type of a column value.
- 
- Default is: 'BytesType', a no-op.
  
  == per-Column Settings ==
   * '''index_name''' and '''index_type'''

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