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https://issues.apache.org/jira/browse/HBASE-13090?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14357867#comment-14357867
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stack commented on HBASE-13090:
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Nice writeup [~jonathan.lawlor]
If only timeout, then maybe premature for ScanLimit unless anything in current
Scan structure that might sit better in ScanLimit?
bq. ....if the client has specified that heartbeats are supported AND partial
results are also supported
This might be ok for 1.1 but partials should be on all the time in 2.0.. This
feature should be on all the time in 2.0. What would be the downsides if
default was to allow return of partials to clients?
On postHeapNext, yeah, ugly, but since you can't specify your own Scanner
implementation serverside (you can't right?), ugly injection is all you have
... so yeah, ugly but we need it (can you make the scan latched rather than
slowed....)
When do I call isHeartbeatMessage? At want point in the processing?
Your reasoning that new session or reset doesn't work makes sense to me.
Will give review on patch later.
Good stuff [~jonathan.lawlor]
> Progress heartbeats for long running scanners
> ---------------------------------------------
>
> Key: HBASE-13090
> URL: https://issues.apache.org/jira/browse/HBASE-13090
> Project: HBase
> Issue Type: New Feature
> Reporter: Andrew Purtell
> Assignee: Jonathan Lawlor
> Attachments: HBASE-13090-v1.patch
>
>
> It can be necessary to set very long timeouts for clients that issue scans
> over large regions when all data in the region might be filtered out
> depending on scan criteria. This is a usability concern because it can be
> hard to identify what worst case timeout to use until scans are
> occasionally/intermittently failing in production, depending on variable scan
> criteria. It would be better if the client-server scan protocol can send back
> periodic progress heartbeats to clients as long as server scanners are alive
> and making progress.
> This is related but orthogonal to streaming scan (HBASE-13071).
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