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https://issues.apache.org/jira/browse/TRAFODION-3260?focusedWorklogId=197374&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-197374
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ASF GitHub Bot logged work on TRAFODION-3260:
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Author: ASF GitHub Bot
Created on: 12/Feb/19 05:21
Start Date: 12/Feb/19 05:21
Worklog Time Spent: 10m
Work Description: Traf-Jenkins commented on issue #1795: [TRAFODION-3260]
SSMP may wait 3 seconds before handling requests
URL: https://github.com/apache/trafodion/pull/1795#issuecomment-462620274
Test Passed. https://jenkins.esgyn.com/job/Check-PR-master/3135/
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Issue Time Tracking
-------------------
Worklog Id: (was: 197374)
Time Spent: 4h 40m (was: 4.5h)
> SSMP may wait 3 seconds before handling requests
> ------------------------------------------------
>
> Key: TRAFODION-3260
> URL: https://issues.apache.org/jira/browse/TRAFODION-3260
> Project: Apache Trafodion
> Issue Type: Bug
> Components: sql-exe
> Affects Versions: any
> Reporter: He Zhenxing
> Priority: Major
> Fix For: 2.4
>
> Time Spent: 4h 40m
> Remaining Estimate: 0h
>
> SSMP may wait and stop responding for up to 3 seconds before handling
> requests. This problem was found while investigating LOB locking issue, which
> may take 3 seconds to acquire the lock.
> Here are the steps to reproduce the issue:
>
> {code:java}
> >> cqd traf_blob_as_varchar 'off';
> >> create table t1 (a blob);
> >> set statistics on;
> >> insert into t1 values (stringtolob('abc'));
> >> insert into t1 values (stringtolob('abc'));
> {code}
>
> We ignore the first insert, which may take long for loading metadata.
> starting from the second, sometimes the insert will take 3 or 6 seconds to
> finish. Normally, it should only take hundreds of milliseconds.
> The problem is because SSMP waiting for client requests from $RECEIVE and
> replies from SSCP separately, so there is a possibility that SSMP is waiting
> on $RECEIVE while there are replies from SSCP and thus it will have to wait
> until timeout (3 seconds) before the replies can be handled and then SSMP can
> reply the client. If both LOB lock and unlock suffered this, the insert will
> take more than 6 seconds to finish.
> This problem also affects other scenarios that need to interact with SSMP.
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