[teiid-issues] [JBoss JIRA] Commented: (TEIID-1596) Document queryThresholdInSecs and allow functionality to ensure user queries take no longer than a specified interval

[Steven Hawkins (JIRA)]

    [ https://issues.jboss.org/browse/TEIID-1596?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12603324#comment-12603324 ] 

Steven Hawkins commented on TEIID-1596:
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queryThresholdInSecs is not directly used by the engine - there is no side effect in the runtime from changing this setting.  It is used and typically configured through RHQ.  It's not expected that users will modify this value directly in the configuration file.

On a related note, there was a recent change so that the client can specify a default query timeout.  It sounds like you would also want a server side setting as well.  That would be its own enhancement, which would also cover any tie into vdb specific overrides.

We de-emphasized the use of maxSourceRows in Teiid since it is a weak method of determining query performance and generally requires the source system to run the full (at least in terms of execution, even if only a limited set of results is returned) query anyway.  You really don't actually end up protecting the backend, but you do possibly prevent excessive query processing in Teiid.

There is a pending request enhancement that is to prevent source query execution based upon a cost determination.  That may be more along the lines of what you're looking for, since that protects the backend - and can cover both queries that have execution complexity and those that simply return lots of rows.

> Document queryThresholdInSecs and allow functionality to ensure user queries take no longer than a specified interval
> ---------------------------------------------------------------------------------------------------------------------
>
>                 Key: TEIID-1596
>                 URL: https://issues.jboss.org/browse/TEIID-1596
>             Project: Teiid
>          Issue Type: Feature Request
>          Components: Server
>    Affects Versions: 7.4
>            Reporter: Graeme Gillies
>            Assignee: Steven Hawkins
>
> In the teiid documentation there is no mention (from what I can find) of exactly what the option queryThresholdInSecs does. The xml file states "Long running query threshold, after which a alert can be generated by tooling if configured", what tooling is this exactly? Does it alert and stop the query, or just alert?
> On the same token, there is the configuration item maxSourceRows which is configured per instance. Unfortunately this isn't flexible enough sometimes, and it would be better if this option could be configured per VDB and per data role as well (some people can get more data than others).
> I would expect the determination of what maxSourceRows is for a query should be as follows
> 1) If maxSourceRows is set for the data role the user has, use that (in the case of two data roles with different values, use the largest value)
> 2) If maxSourceRows is not set on any of the users data role, but set on the vdb, use that value
> 3) If maxSourceRows is not set on the vdb or any data roles the user has, use the instance setting.
> Likewise, the setting maxSourceRows should not only be configurable per data role, vdb, instance, but also the setting queryThresholdInSecs, and either that option or another option should be put in place that allows us to hard limit the length of time a query can run. This is because in teiid we want to be able to say users cannot write a big huge query that will take more than X amount of seconds to execute, to stop someone in teiid giving it a huge query and hammering all the backend databases. Configuring this option by vdb and data role (as some people are more trusted and can run longer queries) would be fantastic.

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