[jira] [Comment Edited] (KUDU-1767) Reordering of client operations from the same KuduSession is possible

["Mike Percy (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/KUDU-1767?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15813718#comment-15813718 ] 

Mike Percy edited comment on KUDU-1767 at 1/10/17 3:29 AM:
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After discussing this issue with a couple of folks, I am marking this issue Won't Fix for the following reasons:

# This behavior does not violate strict serializability because we are talking about operations that occur simultaneously from Kudu's perspective.
# There are workarounds for the observed behavior.

Systems that want to write in a particular order can choose to flush one batch at a time to avoid reordering. If single-key ordering conflicts are the primary concern, care can also be taken by client programs to flush an update to a single key before apply()ing a following update to that key while still maintaining some parallelism at load time.


was (Author: mpercy):
After discussing this issue with a couple of folks, I am marking this issue Won't Fix for the following reasons:

# This behavior does not violate strict serializability because we are talking about operations that occur simultaneously from Kudu's perspective.
# There are workarounds for the observed behavior.

For systems that want to write in a particular order, then can choose to flush one batch at a time to avoid reordering. If single-key ordering conflicts are the primary concern, care can also be taken by client programs to flush an update to a single key before apply()ing the following update to that key.

> Reordering of client operations from the same KuduSession is possible
> ---------------------------------------------------------------------
>
>                 Key: KUDU-1767
>                 URL: https://issues.apache.org/jira/browse/KUDU-1767
>             Project: Kudu
>          Issue Type: Bug
>          Components: client, tablet
>    Affects Versions: 1.1.0
>            Reporter: Mike Percy
>            Priority: Critical
>             Fix For: n/a
>
>
> It is possible for client operations written via the same KuduSession to be reordered on the server side in MANUAL_FLUSH and AUTO_BACKGROUND_FLUSH modes. This violates our desired consistency guarantees.
> This may occur because we allow concurrent flushes from the client for throughput reasons and there is nothing enforcing the well-ordering of lock acquisition from a single client session on the server side.



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