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From "Lily Wei (JIRA)" <j...@apache.org>
Subject [jira] Updated: (DERBY-4771) Continue investigation of automatic creation/update of index statistics
Date Tue, 31 Aug 2010 18:37:53 GMT

     [ https://issues.apache.org/jira/browse/DERBY-4771?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel

Lily Wei updated DERBY-4771:

    Attachment: rjall.out

Hi Kristian:
     Thank you so much for doing this. This will be a great plus for Derby in my opinion.

     Overall, I like the design. Having a daemon gathering statistic and execute in a separate
thread is a common statistic gathering implementation strategy.  I agree that the memory consumption
should be little for the implementation. At the compilation process, new statistic for the
query is written along with completed statistics to the data dictionary with a nested read-write
user transaction.  And, we will not wait for new statistics to be generated. Should we have
more detail priority strategy in turn of how and when completed statistic gets written to
data dictionary associate with query complete time and new statistic? i.e. For the case we
write and the cases we don't wait for too long of time consideration.
I am not sure this is cover in the weaknesses already or the  NO_WAIT option in the call to
add new 
   descriptors to the data dictionary.  I personally was not clear in turn of the implementation
on compilation time. So, any elaboration on compilation process for the current operation
and additional with new statistics and completed statistics information written to data directory
will be very helpful to me.

     I include my run(rjall.out) for Suites.All on Windows 7 with jdk1.6.0_13 32 bits with
my comments. This is just for reference in case we can see other issues were not mention already.

> Continue investigation of automatic creation/update of index statistics
> -----------------------------------------------------------------------
>                 Key: DERBY-4771
>                 URL: https://issues.apache.org/jira/browse/DERBY-4771
>             Project: Derby
>          Issue Type: Task
>            Reporter: Kristian Waagan
>         Attachments: derby-4771-1a-prototype_code_dump.diff, derby-4771-1a-prototype_code_dump.stat,
> Work was started to improve Derby's handling of index statistics. This issue tracks further
discussion and work for this task.

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