[teiid-issues] [JBoss JIRA] (TEIID-2795) TTL Snapshot Refresh doesn't fully reload Internal MV if the user query contains LIMIT

[Steven Hawkins (JIRA)]

     [ https://issues.jboss.org/browse/TEIID-2795?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Steven Hawkins updated TEIID-2795:
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    Attachment: TEIID-2795.patch


Here's a back port of the relevant changes from 8.4.  It may also make some sense (perhaps a config option) to have the request that initiates the refresh perform a blocking refresh even in the ttl case.
                
> TTL Snapshot Refresh doesn't fully reload Internal MV if the user query contains LIMIT
> --------------------------------------------------------------------------------------
>
>                 Key: TEIID-2795
>                 URL: https://issues.jboss.org/browse/TEIID-2795
>             Project: Teiid
>          Issue Type: Bug
>          Components: Query Engine
>    Affects Versions: 7.7.8
>            Reporter: Debbie Steigner
>            Assignee: Steven Hawkins
>         Attachments: TEIID-2795.patch
>
>
> using the cache hint to automatically trigger a full snapshot refresh after a specified time to live (TTL)[1]. The TTL works but if the user query that is run contains a LIMIT clause the refresh load uses the LIMIT and doesn't completely load the internal MV and fails load.
> Sequence of events
> 1) Execute the query to initiate the internal MV load
> 2) After caching, issue the same query but with limit of 10,000 to test it is hitting the cache
> 3) Wait for 5 minutes for TTL to expire
> 4) Re-issue the same query with limit of 10,000 and i can see the state change to reloading but once the query has finished fetching 10,000 from data source it terminates and the MV state changed to failed_load. I would have expected the MV to continue to load to rehydrate the cache and the query should be fetching the data from the stale cache. But this is not the case ... 
> [1]https://access.redhat.com/site/documentation/en-US/JBoss_Enterprise_Data_Services/5/html/Data_Services_Caching_Guide/matviews.html#idp7629936

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