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From "Knut Anders Hatlen (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (DERBY-6003) Create row templates outside of the generated code
Date Tue, 27 Nov 2012 13:35:58 GMT

     [ https://issues.apache.org/jira/browse/DERBY-6003?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Knut Anders Hatlen updated DERBY-6003:
--------------------------------------

    Attachment: d6003-2a-unused-field.diff

To fix the above mentioned deserialization problem in DataTypeDescriptor, I think we need
to make DataTypeDescriptor.readExternal() call TypeId.getUserDefinedTypeId() instead of TypeId.getBuiltInTypeId()
if it's a user-defined type.

The getUserDefinedTypeId() takes a boolean parameter called delimitedIdentifier. I don't know
what's the right value to pass in. But looking closer at it, it looks like the value is never
used, and all callers pass in false. So to make the final patch simpler, I'm attaching another
cleanup patch (d6003-2a-unused-field.diff) that removes this dead code. That should be an
improvement regardless of how we end up fixing the rest of the issue.

All tests ran cleanly with the 2a patch.
                
> Create row templates outside of the generated code
> --------------------------------------------------
>
>                 Key: DERBY-6003
>                 URL: https://issues.apache.org/jira/browse/DERBY-6003
>             Project: Derby
>          Issue Type: Improvement
>          Components: SQL
>    Affects Versions: 10.10.0.0
>            Reporter: Knut Anders Hatlen
>            Assignee: Knut Anders Hatlen
>            Priority: Minor
>         Attachments: d6003-1a-cleanup.diff, d6003-2a-unused-field.diff
>
>
> The constructors for many of the result set classes take GeneratedMethod parameters that
create row templates (an ExecRow of a certain size and column types, each column initialized
to an SQL null value).
> As an alternative, the compiler could produce an ExecRow instance and put it into the
savedObjects field of GenericPreparedStatement, and the constructors could take parameter
that points to the object in savedObjects. Where the result sets currently invoke the generated
method to produce a fresh template, they could instead clone the saved object.
> Advantages with the suggested approach would be:
> - Reduce the size of the code generator, which should reduce total code complexity.
> - Reduce the amount of generated code, which makes it easier for tools (profilers, static
code analyzers, IDEs) to map executable code to source code.
> - Reduce the actual number of generated methods, which makes it less likely that queries
need to use reflection to invoke the remaining generated methods (there's a switchover from
DirectCall to ReflectCall when the number of generated methods exceeds 10).

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