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https://issues.apache.org/jira/browse/DERBY-716?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12493697
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Rick Hillegas commented on DERBY-716:
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Thanks for helping me puzzle through the usage of VTIEnvironment, Dan. How does
the following sound:
1) Leave the VTIEnvironment arguments in the VTICosting methods.
2) Remove isCompileTime() from VTIEnvironment.
3) Beef up the javadoc for VTIEnvironment:
a) Note that it is information used only by user-written costing logic.
b) It allows user-written costing methods to share information with each other.
c) Its lifetime is the lifetime of a statement plan in Derby's statement
cache. If the invoking statement has to be recompiled, then the VTIEnvironment
variable can be used to share information across re-compilations.
If we are going to use VTIEnvironment, then I think the user guides should give
an example of how to exploit this variable.
> Re-enable VTIs
> --------------
>
> Key: DERBY-716
> URL: https://issues.apache.org/jira/browse/DERBY-716
> Project: Derby
> Issue Type: New Feature
> Components: SQL
> Reporter: Rick Hillegas
> Attachments: functionTables.html, functionTables.html
>
>
> Cloudscape used to expose Virtual Table Interfaces, by which any class which
> implemented ResultSet could be included in a query's FROM list. Derby still
> exposes a number of these VTIs as diagnostic tools. However, Derby now
> prevents customers from declaring their own VTIs. The parser raises an error
> if a VTI's package isn't one of the Derby diagnostic packages.
> This is a very powerful feature which customers can use to solve many
> problems. We should discuss the reasons that it was disabled and come up with
> a plan for putting this power back into our customers' hands.
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