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From "Mike Matrigali (JIRA)" <derby-...@db.apache.org>
Subject [jira] Resolved: (DERBY-741) row estimates from btree code can sometimes return more row than exist in table
Date Mon, 05 Dec 2005 18:40:08 GMT
     [ http://issues.apache.org/jira/browse/DERBY-741?page=all ]
     
Mike Matrigali resolved DERBY-741:
----------------------------------

    Fix Version: 10.2.0.0
                 10.1.3.0
     Resolution: Fixed

svn 354106 fixes it in 10.1
svn 351846 fixes it in the trunk

fix for DERBY-741.

Insure that row estimates from btree cost function never return more rows than
the btree thinks it has.  Before this change an ASSERT might fire where the
fraction estimating the percentage of rows became larger than 1 (like 1.000001).

> row estimates from btree code can sometimes return more row than exist in table
> -------------------------------------------------------------------------------
>
>          Key: DERBY-741
>          URL: http://issues.apache.org/jira/browse/DERBY-741
>      Project: Derby
>         Type: Bug
>   Components: Store
>     Versions: 10.0.2.0, 10.0.2.1, 10.1.1.0, 10.1.1.1, 10.1.1.2, 10.1.2.0, 10.1.2.1
>     Reporter: Mike Matrigali
>     Assignee: Mike Matrigali
>     Priority: Minor
>      Fix For: 10.2.0.0, 10.1.3.0

>
> In BTreeCostController the recursive row estimate can sometimes return more rows than
exists in the table.  In Sane server an ASSERT would be thrown.  Simple change is to just
always make the max estimation be all the rows in the table.

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