[jira] [Updated] (CONNECTORS-618) MySQL orders null values to the front of the index, which breaks the stuffing query

["Karl Wright (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CONNECTORS-618?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Karl Wright updated CONNECTORS-618:
-----------------------------------

    Fix Version/s: ManifoldCF 1.1
    
> MySQL orders null values to the front of the index, which breaks the stuffing query
> -----------------------------------------------------------------------------------
>
>                 Key: CONNECTORS-618
>                 URL: https://issues.apache.org/jira/browse/CONNECTORS-618
>             Project: ManifoldCF
>          Issue Type: Bug
>          Components: Framework core
>    Affects Versions: ManifoldCF 1.0.1, ManifoldCF 1.1
>            Reporter: Karl Wright
>            Assignee: Karl Wright
>             Fix For: ManifoldCF 1.1
>
>
> MySQL attempts to read all null values from the docpriority index before it encounters anything useful.  If there are a lot of records from other stopped jobs around, this makes ManifoldCF stuffing very slow.
> There is no way to cause MySQL to order null values in indexes differently, unfortunately.  So the only options are:
> (1) Use a special value instead of NULL, which is problematic because this column contains a float, and therefore has rounding errors;
> (2) Use null, but order the index backwards in the case of MySQL.  This implies that we need to actually change what we put in as a data value based on database type - doable but also definitely scary.

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