Sebastian Toader created AMBARI-19164:
-----------------------------------------
Summary: Add PK to hostcomponentdesiredstate Table To Support FK
Relationships
Key: AMBARI-19164
URL: https://issues.apache.org/jira/browse/AMBARI-19164
Project: Ambari
Issue Type: Bug
Components: ambari-server
Reporter: Sebastian Toader
Assignee: Sebastian Toader
Priority: Critical
Fix For: 2.5.0
The {{hostcomponentdesiredstate}} table currently uses a compound PK based off
of the cluster ID, service name, host id 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 {{hostcomponentdesiredstate}} table would now
need knowledge of cluster/service/component/host 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.
This table needs to be changed 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
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
