keith-turner opened a new issue, #5010:
URL: https://github.com/apache/accumulo/issues/5010

   **Is your feature request related to a problem? Please describe.**
   
   The Manager maintains a set of migrating tablets in memory and this in 
memory set tightly couples the tablet group watcher and balancer code.  When 
there is a problem it would be useful to see the contents of this set, logging 
provides perdiodic information on this but its cumbersome.
   
   
   **Describe the solution you'd like**
   
   Remove the in memory set and replace it with a column in the metadata table 
that is set in the source tablet and has a value of the destination tablet.  
Hopefully this will avoid the need for the balancer code to pass this set to 
the tablet group watcher code which in turn passes the set to iterators for 
filtering.  The filtering iterators could see the column in the metadata table 
and would not longer need to pass this potentially large set around.
   
   This change should also make it easy to see the contents of the set at any 
time via a metadata table scan.
   
   **Describe alternatives you've considered**
   
   The in memory set could be kept and one manager process could request it 
from another via RPC in order to  support multiple managers.  Placing the set 
in the metadata table has benefits for filtering and observe-ability that the 
RPC would not have.  Also the metadata approach may be simple to keep 
consistent. 
   
   **Additional context**
   
   This change is probably a pre-requisite change to multiple managers because 
it removes an in memory dependencies between different functional components in 
the manager and moves those from memory to the metadata table.  This makes it 
possible to run those different functional components in different processes.


-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: notifications-unsubscr...@accumulo.apache.org.apache.org

For queries about this service, please contact Infrastructure at:
us...@infra.apache.org

Reply via email to