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https://issues.apache.org/jira/browse/KUDU-3498?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Xixu Wang updated KUDU-3498:
----------------------------
Description:
Kudu caches the scanner id in the tablet server for continuing reading. It will
be expired if the idle time is over the defined scanner ttl time. Sometimes the
client reads a batch of data, if the data is every large, it takes a long time
to handle it. Then the client reads the next batch using the same scanner, the
scanner will be expired even if it has send a keep alive requests.
There is an example:
/main/logs/sp/kudu/tserver/3.kudu.log.INFO.20230731-143052.2665:I0731
14:57:19.307266 9280 scanners.cc:280] Expiring scanner id:
a279f6e3715d437d935d0bd79788c591, of tablet 0f8f4920ba514624abc294c7c64725c1,
after 184023 ms of inactivity, which is > TTL (180000 ms).
/main/logs/sp/kudu/tserver/kudu.log.INFO.20230731-143052.2665:I0731
15:03:07.419070 9289 tablet_service.cc:2957] Scan: Not found: Scanner
a279f6e3715d437d935d0bd79788c591 not found (it may have expired): call sequence
id=10, remote=\{username='impala'} at host:26278
The client takes 9 minutes to handle a batch of data, but the scanner has
already been expired.
> Scanner keeps alive in periodically
> -----------------------------------
>
> Key: KUDU-3498
> URL: https://issues.apache.org/jira/browse/KUDU-3498
> Project: Kudu
> Issue Type: Improvement
> Reporter: Xixu Wang
> Priority: Major
>
> Kudu caches the scanner id in the tablet server for continuing reading. It
> will be expired if the idle time is over the defined scanner ttl time.
> Sometimes the client reads a batch of data, if the data is every large, it
> takes a long time to handle it. Then the client reads the next batch using
> the same scanner, the scanner will be expired even if it has send a keep
> alive requests.
> There is an example:
> /main/logs/sp/kudu/tserver/3.kudu.log.INFO.20230731-143052.2665:I0731
> 14:57:19.307266 9280 scanners.cc:280] Expiring scanner id:
> a279f6e3715d437d935d0bd79788c591, of tablet 0f8f4920ba514624abc294c7c64725c1,
> after 184023 ms of inactivity, which is > TTL (180000 ms).
> /main/logs/sp/kudu/tserver/kudu.log.INFO.20230731-143052.2665:I0731
> 15:03:07.419070 9289 tablet_service.cc:2957] Scan: Not found: Scanner
> a279f6e3715d437d935d0bd79788c591 not found (it may have expired): call
> sequence id=10, remote=\{username='impala'} at host:26278
>
> The client takes 9 minutes to handle a batch of data, but the scanner has
> already been expired.
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