[
https://issues.apache.org/jira/browse/HBASE-6295?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13617639#comment-13617639
]
Nicolas Liochon commented on HBASE-6295:
----------------------------------------
The table multiplexers has two drawbacks imho:
- it's a new interface
- it manages errors by dropping the puts that failed.
This is suitable for some applications, but not all of them.
I think it's possible to do something in the middle, and stick to the existing
interface. This would be:
- we set two value for the write buffer: backgroundThreshold and
blockingThreshold.
- blockingThreshold works as today: we flush and block the callers until it's
sent successfully
- when backgroundThreshold is reached, we send data in the background, without
blocking the user
- if we have too many errors we do as today: empty the buffer and raise the
error to the user at the next put.
- flushCommit and puts works as today.
- We keep the existing table behavior, and try, as today, to have not
synchronization in the HTable code.
Other comments:
- if we want to be very efficient when merging calls to a given region server
for different tables, we should add this in the protobuf protocol.
- if we change the messages sent to the region server, we could also let the
region server return a workload info. This workload would be used by the client
to slow down their messages. Some clients could have a 'nice' parameter to slow
down more than others (typically map reduce jobs).
I will give a try to the send in background to see if it's possible to have
something reasonable.
> Possible performance improvement in client batch operations: presplit and
> send in background
> --------------------------------------------------------------------------------------------
>
> Key: HBASE-6295
> URL: https://issues.apache.org/jira/browse/HBASE-6295
> Project: HBase
> Issue Type: Improvement
> Components: Client, Performance
> Affects Versions: 0.96.0
> Reporter: Nicolas Liochon
> Labels: noob
>
> today batch algo is:
> {noformat}
> for Operation o: List<Op>{
> add o to todolist
> if todolist > maxsize or o last in list
> split todolist per location
> send split lists to region servers
> clear todolist
> wait
> }
> {noformat}
> We could:
> - create immediately the final object instead of an intermediate array
> - split per location immediately
> - instead of sending when the list as a whole is full, send it when there is
> enough data for a single location
> It would be:
> {noformat}
> for Operation o: List<Op>{
> get location
> add o to todo location.todolist
> if (location.todolist > maxLocationSize)
> send location.todolist to region server
> clear location.todolist
> // don't wait, continue the loop
> }
> send remaining
> wait
> {noformat}
> It's not trivial to write if you add error management: retried list must be
> shared with the operations added in the todolist. But it's doable.
> It's interesting mainly for 'big' writes
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
