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From Apache Wiki <wikidi...@apache.org>
Subject [Cassandra Wiki] Update of "ArchitectureCommitLog" by JingguoYao
Date Thu, 14 Oct 2010 15:05:16 GMT
Dear Wiki user,

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

The "ArchitectureCommitLog" page has been changed by JingguoYao.
The comment on this change is: Disable link.
http://wiki.apache.org/cassandra/ArchitectureCommitLog?action=diff&rev1=4&rev2=5

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

  Each insertion (deletion) has to first write a log entry to the !CommitLog.
  
   * The writing of all log entries is handled by a single thread in !CommitLogExecutorService.
-  * For the first insert to a given !ColumnFamily CF in each !CommitLogSegment, the !CommitLogHeader
is updated: the CF's dirty bit is turned on and the replay offset for CF in the !CommitLogHeader
is updated with the current position (represented by a !CommitLogContext object) in the CommitLog
file.
+  * For the first insert to a given !ColumnFamily CF in each !CommitLogSegment, the !CommitLogHeader
is updated: the CF's dirty bit is turned on and the replay offset for CF in the !CommitLogHeader
is updated with the current position (represented by a !CommitLogContext object) in the !CommitLog
file.
   * A !RowMutation entry is then appended to the !CommitLogSegment
   * If !CommitLogSync is set to batch, the insertion further waits until the !CommitLogSegment
is sync-ed to disk before the insert is allowed to proceed
   * Once a !CommitLogSegment becomes too large, a new segment is created and new operations
are appended there instead.

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