couchdb-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Apache Wiki <wikidi...@apache.org>
Subject [Couchdb Wiki] Trivial Update of "Compaction" by sergeyk
Date Thu, 12 Jun 2008 19:44:48 GMT
Dear Wiki user,

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

The following page has been changed by sergeyk:
http://wiki.apache.org/couchdb/Compaction

The comment on the change is:
Minor correction on "Additional Info", renamed to Compaction of write-heavy dbs

------------------------------------------------------------------------------
  
  The compact_running key will be set to true during compaction.
  
- === Additional Information ===
+ === Compaction of write-heavy databases ===
  Note, it is not a good idea to attempt compaction on a database is near full capacity for
its write load. The problem is the compaction process may never catch up with the writes if
they never let up, and eventually it will run out of disk space.
  
  Compaction should be attempted when the write load is less than full capacity. Read load
won't affect its ability to complete however.
  CouchDB works like this to have the least impact possible on clients,  the database remains
online and fully functional to readers and  
  writers. It is a design limitation that database compaction can't complete when at capacity
for write load. It may be reasonable to schedule compactions during off-peak hours. 
  
- In a clustered environment the write load can switched off for any node before compaction
and brought back up to date with  
+ In a clustered environment the write load can be switched off for any node before compaction
and brought back up to date with  
  compaction once complete. 
  
  In the future, a single CouchDB node can be changed to stop or fail other updates if the
write load is too heavy for it to complete in a  reasonable time.

Mime
View raw message