Couchbase http://www.couchbase.com/issues This file is an XML representation of an issue en-us 5.2.4 845 26-12-2012 [MB-4937] ep-engine provides disk fragmentation statistics http://www.couchbase.com/issues/browse/MB-4937 Couchbase Server Currently, there is no easy way to understand the disk fragmentation of SQLite. Expose this stat that should be calculated in ep_engine and exposed via REST API and the UI to better understand SQLite fragmentation over time so that users can understand when maintenance of the system using swap rebalance, vacuuming or other methods is required. MB-4937 ep-engine provides disk fragmentation statistics Improvement Major Resolved Fixed Public Chiyoung Seo Dipti Borkar Thu, 22 Mar 2012 09:11:49 -0500 Mon, 14 May 2012 12:25:24 -0500 Tue, 3 Apr 2012 17:30:36 -0500 1.7.2 1.8.0 1.8.1 0 0 ns_server can grab histogram from ep-engine and calculate average. to add usage notes The stat subkey is &quot;kvtimings&quot;. For example, the following shows how we can grab read/write seek histograms from the underlying kvstore: <br/> <br/> Chiyoung-MacBook:ep-engine chiyoung$ ./management/cbstats 127.0.0.1:11210 kvtimings <br/> &nbsp;readSeek (23 total) <br/> &nbsp;&nbsp;&nbsp;&nbsp;0 - 2 : ( 21.74%) 5 ########################### <br/> &nbsp;&nbsp;&nbsp;&nbsp;8 - 16 : ( 26.09%) 1 ##### <br/> &nbsp;&nbsp;&nbsp;&nbsp;64 - 128 : ( 47.83%) 5 ########################### <br/> &nbsp;&nbsp;&nbsp;&nbsp;256 - 512 : ( 73.91%) 6 ################################# <br/> &nbsp;&nbsp;&nbsp;&nbsp;512 - 1KB : ( 78.26%) 1 ##### <br/> &nbsp;&nbsp;&nbsp;&nbsp;1KB - 2KB : ( 95.65%) 4 ###################### <br/> &nbsp;&nbsp;&nbsp;&nbsp;2KB - 4KB : (100.00%) 1 ##### <br/> &nbsp;writeSeek (77 total) <br/> &nbsp;&nbsp;&nbsp;&nbsp;4 - 8 : ( 28.57%) 22 #################################### <br/> &nbsp;&nbsp;&nbsp;&nbsp;8 - 16 : ( 36.36%) 6 ######### <br/> &nbsp;&nbsp;&nbsp;&nbsp;16 - 32 : ( 57.14%) 16 ########################## <br/> &nbsp;&nbsp;&nbsp;&nbsp;256 - 512 : ( 61.04%) 3 #### <br/> &nbsp;&nbsp;&nbsp;&nbsp;512 - 1KB : ( 84.42%) 18 ############################# <br/> &nbsp;&nbsp;&nbsp;&nbsp;1KB - 2KB : ( 97.40%) 10 ################ <br/> &nbsp;&nbsp;&nbsp;&nbsp;2KB - 4KB : (100.00%) 2 ### <br/> Chiyoung, can you provide some guidelines about what these mean, and how to interpret them so that we can add to the documentation. These timings show the distribution of disk head seek distance that have been performed on every read / write operation on Sqlite. We expect that these seek distance would be increased over the time as the sqlite is getting fragmented more and more. Date of First Response Tue, 3 Apr 2012 16:37:15 -0500 Rank 5255 Time In Status