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https://issues.apache.org/jira/browse/HBASE-17045?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15819071#comment-15819071
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Enis Soztutar commented on HBASE-17045:
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Thanks Duo for working on this. I have a couple of high-level feedback, so let
me do it here rather than RB.
Instead of adding a limit to the scan, which enforces to know the exact size of
the "small" scan, should we instead do it so that even if you don't know the
size, if a scan exhausts the region, it is automatically closed. Can we instead
add a flag to the {{ScanResponse}} from the server side indicating that the
server has exhausted the region, and also closed the scanner? This way, we do
not need the limit, since server will tell the client that the scan is already
closed. If if happens that in the open scan RPC, the first batch to grab the
results exhausts the region, then the scanner is closed, and the RPC response
indicates that.
One more question I had is that I do not see changes for the snyc client, is it
already handling the case where the open scanner RPC can return some results?
> Unify the implementation of small scan and regular scan
> -------------------------------------------------------
>
> Key: HBASE-17045
> URL: https://issues.apache.org/jira/browse/HBASE-17045
> Project: HBase
> Issue Type: Sub-task
> Components: Client, scan
> Affects Versions: 2.0.0
> Reporter: Duo Zhang
> Assignee: Duo Zhang
> Fix For: 2.0.0
>
> Attachments: HBASE-17045-v1.patch, HBASE-17045-v2.patch,
> HBASE-17045.patch
>
>
> See [~enis]'s comment in HBASE-16838
> https://issues.apache.org/jira/browse/HBASE-16838?focusedCommentId=15637803&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15637803
> But there is another scenario that we need small scan is that, we do not know
> the stop row but we only want a small set of results. For example, in the
> implementation of region locator, we will use small scan and set caching to 1
> as we only need one row.
> So I think we need to add a new option(maybe called limit?) for the scan
> object, and deprecate the small option. And the server side modification
> should also be committed to branch-1 to simplify the logic of async client in
> 2.0.
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