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https://issues.apache.org/jira/browse/DERBY-4115?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Mamta A. Satoor updated DERBY-4115:
-----------------------------------

    Attachment: DERBY4115_patch4_diff.txt

Attaching patch, DERBY4115_patch4_diff, which is same as previous patch but now 
has changes to sqlgrammar.,jj to recognize the internal syntax ALTER TABLE 
tablename ALL DROP STATISTICS or ALTER TABLE tablename DROP STATISTICS 
indexname. Currently, this just calls the code for update statistics. This is 
of course wrong but I wanted to see that the basic framework to support new 
syntax works in the grammar.

Next, I plan to change the new procedure to actually send the ALTER TABLE DROP 
STATISTICS call when the procedure is invoked.

After thatt, I plan to make changes so that we call some dummy code(as the 
first step) in alter table when DROP STATISTICS is requested by the new stored 
procedure through the sql grammar..
                
> Provide a way to drop statistics information
> --------------------------------------------
>
>                 Key: DERBY-4115
>                 URL: https://issues.apache.org/jira/browse/DERBY-4115
>             Project: Derby
>          Issue Type: Improvement
>          Components: SQL
>    Affects Versions: 10.6.1.0
>            Reporter: Kathey Marsden
>            Assignee: Mamta A. Satoor
>         Attachments: DERBY4115_patch1_diff.txt, DERBY4115_patch2_diff.txt, 
> DERBY4115_patch3_diff.txt, DERBY4115_patch4_diff.txt
>
>
> Now that DERBY-269 has been resolved,  users can update statistics, but once 
> they do, they are committed to using and maintaining the statistics, even if 
> it doesn't improve performance or they have difficulty maintaining the 
> statistics on a regular basis.  It would be good to have a way to drop 
> statistics information so that users could revert to the prior behavior if 
> needed.

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