accumulo-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Keith Turner (Created) (JIRA)" <>
Subject [jira] [Created] (ACCUMULO-112) Investigate partitioning in memory map by locality group
Date Wed, 02 Nov 2011 15:41:32 GMT
Investigate partitioning in memory map by locality group

                 Key: ACCUMULO-112
             Project: Accumulo
          Issue Type: Task
          Components: tserver
            Reporter: Keith Turner
            Assignee: Keith Turner

Currently the in memory map is not partitioned by locality group.  This could negatively impact
scan and minor compaction performance.    Would like to run some experiments to understand
the performance implications.  Partitioning by locality group could negatively impact insert
performance, it could go from O(log(R)+log(C))  to O(L * (log(R)+log(C))) in the worst case.
 L is the number of locality groups, R is the number of rows and C is the number of columns.
 The worst case is where each mutation has a change for each locality group. 

Currently the in memory map is a map of maps.  Like the following.

  map<row, map<col, val>>

Could conceptually change this to one of the following.  The first is best for scans, that
access some locality groups, and minor compactions.  The second is good for inserts where
the mutation covers all locality groups, because the row is only looked up once.

  map<localityGroup, map<row, map<col, val>>>

  map<row, map<localityGroup, map<col, val>>>

This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:!default.jspa
For more information on JIRA, see:


View raw message