db-derby-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Rick Hillegas (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-716) Re-enable VTIs
Date Fri, 04 May 2007 14:06:15 GMT

    [ https://issues.apache.org/jira/browse/DERBY-716?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12493697
] 

Rick Hillegas commented on DERBY-716:
-------------------------------------

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.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


Mime
View raw message