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From "Jonathan Hurley (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (AMBARI-14972) Add PK to servicecomponentdesiredstate Table To Support FK Relationships
Date Tue, 09 Feb 2016 14:42:18 GMT

     [ https://issues.apache.org/jira/browse/AMBARI-14972?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Jonathan Hurley updated AMBARI-14972:
-------------------------------------
    Attachment: AMBARI-14972.patch

> Add PK to servicecomponentdesiredstate Table To Support FK Relationships
> ------------------------------------------------------------------------
>
>                 Key: AMBARI-14972
>                 URL: https://issues.apache.org/jira/browse/AMBARI-14972
>             Project: Ambari
>          Issue Type: Task
>          Components: ambari-server
>    Affects Versions: 2.4.0
>            Reporter: Jonathan Hurley
>            Assignee: Jonathan Hurley
>            Priority: Critical
>             Fix For: 2.4.0
>
>         Attachments: AMBARI-14972.patch
>
>
> The {{servicecomponentdesiredstate}} table currently uses a compound PK based off of
the cluster ID, service name, and component name. There are several problems with this approach:
> - Primary Keys should be data that's not part of the business logic of the system and
not subject to be changed potentially (as strings are).
> - Other tables referencing the {{servicecomponentdesiredstate}} table would now need
knowledge of cluster/service/component in order to make the correct FK association. This leads
to extra data being tracked as well as data duplication.
> - Some databases, such as SQL Server, have problems with the indexing of compound PKs
and may lead to deadlocks when querying and updating concurrently.
> We should change this table so that it uses a simple PK for referencing. FK relationships
as they exist today can still be maintained as long as a {{UNIQUE}} constraint is placed on
the table. We should:
> - Add a {{UNIQUE}} constraint to the former PK columns
> - Add an {{INDEX}} to the former PK columns



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