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From "Kristian Waagan (JIRA)" <j...@apache.org>
Subject [jira] Updated: (DERBY-4214) Inconsistent metadata for CLOBGETSUBSTRING, depending on your upgrade trajectory
Date Tue, 16 Jun 2009 20:15:07 GMT

     [ https://issues.apache.org/jira/browse/DERBY-4214?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel

Kristian Waagan updated DERBY-4214:

    Attachment: performance-numbers.txt

With regards to DERBY-3769, the performance of F and H should be the same.

See the attached file 'performance-numbers.txt' for some numbers on the performance improvements
in 10.5. Note also the difference between running 10.5 with the fix and without the fix for
the ASCII/latin Clob. The difference will be more significant with larger Clobs, and improving
the situation is tracked by DERBY-3918. Compared to the 10.4 performance, this performance
hit is peanuts though!

> Inconsistent metadata for CLOBGETSUBSTRING, depending on your upgrade trajectory
> --------------------------------------------------------------------------------
>                 Key: DERBY-4214
>                 URL: https://issues.apache.org/jira/browse/DERBY-4214
>             Project: Derby
>          Issue Type: Bug
>          Components: SQL
>    Affects Versions:,,,
>            Reporter: Rick Hillegas
>         Attachments: performance-numbers.txt
> The on-disk signature of CLOBGETSUBSTRING changed as a result of the work done on DERBY-3769.
Previously, the return type of that function was VARCHAR(32672). The return type changed to
VARCHAR(10890) with revision 707097, which made it into release That change was
also backported to the 10.4 branch at 711548. However, no upgrade logic was written to support
this metadata change. As a result, we have two discrepancies with our upgrade policy:
> 1) If you upgrade a database to, the signature of CLOBGETSUBSTRING will not
be the signature which you would see in a freshly created database. Presumably this
means that the problem addressed by DERBY-3769 is not solved in upgraded databases.
> 2) If we create another release on the 10.4 branch, then we will have a change in on-disk
metadata introduced by a bug-fix release.
> I see two solutions:
> A) Add metadata upgrade logic to the 10.4 and 10.5 branches so that DERBY-3769 will be
fixed in upgraded databases as well as freshly created databases. This will violate our policy
of not changing on-disk metadata in maintenance releases.
> B) Correct the metadata in the hard-upgrade logic of 10.6. We may want to revert the
10.4 backport.
> In any event, we may also want to re-open DERBY-3769 to indicate that the bug is not
fixed in hard-upgraded databases but only in freshly created databases.
> What are people's thoughts about how to address this discrepancy?

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