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https://issues.apache.org/jira/browse/PHOENIX-5090?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16734981#comment-16734981
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Lars Hofhansl commented on PHOENIX-5090:
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Hmm... I forgot to mention that part. Thanks for pointing that out.
My thought is that we can (perhaps optionally) start with an optimistic
assumption that the transaction won't conflict or be rolled back. If now there
is a conflict or rollback it'd need to handled the same way as a client
crashing before it can cleanup any partial writes.
Hmm again... Maybe it's not worth the effort. It just seems ... unfortunate ...
that we have a scalable database in the background but need to limit the size
of any given transaction to what can be buffered at the client.
Perhaps we need another setting to set the transactional batch-size...? 2MB are
near perfect for most networks. So we should keep that for non-transactional
mutations. For transactions we should allow increasing that so that larger
transactions can be handled (without compromising the non-transactional case)
> Discuss: Allow transactional writes without buffering the entire transaction
> on the client.
> -------------------------------------------------------------------------------------------
>
> Key: PHOENIX-5090
> URL: https://issues.apache.org/jira/browse/PHOENIX-5090
> Project: Phoenix
> Issue Type: Wish
> Reporter: Lars Hofhansl
> Priority: Major
>
> Currently it is not possible execute transactions in Phoenix that are too
> large to be buffered entirely on the client.
> Both Tephra and Omid support writing uncommitted data to HBase immediately
> and at full speed. The client still needs to keep tracks of the rows changes
> for:
> # Conflict detection
> # (for Omid) writing the shadow cells
> I'd like to do some brainstorming here.
> * It should *always* be enough to only hold on to the changed rows (and
> columns?) only for _conflict resolution_ and free the rest from the client as
> soon as the uncommitted data is written to HBase.
> * For the shadows cells we need only keep the rows changed, right?
> * There are situations where we can avoid the client site buffering entirely
> (perhaps only for Tephra) when we declare a table or upsert not to
> participate in conflict resolution.
> [~tdsilva], [~ohads], [~yonigo], [~jamestaylor], [~vincentpoon], more, better
> ideas?
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