[teiid-issues] [JBoss JIRA] Commented: (TEIID-207) Forward and Backward Compatibility of MetaMatrix JDBC Driver

Tue Apr 20 10:08:49 EDT 2010

    [ https://jira.jboss.org/jira/browse/TEIID-207?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12526597#action_12526597 ] 

Steven Hawkins commented on TEIID-207:
--------------------------------------

The compatibility approach will be:

1. The compactobject stream logic will only omit descriptor information for non-primitive, non-externalizable classes.  Since client and server may be running different vms we want to accurately convey the field information for serializable classes (many of which we don't control).  It follows that any class that is just serializable will still write the full serialization information to the stream - which necessitates adding the serial version ids. 

2. Our most commonly used externalizable classes will be built into the protocol to eliminate the need of even writing their full classnames as their descriptors (which makes it easier to refactor).  See CompactObjectOutputStream where these classes are registered.

3. It follows from 2, that we'll use externalizable where ever possible.  For the first cut this will include all non-admin api logic.  The exteranizable contract will then be maintained so that it is backwards compatible - additional fields may be added though with any issues.

4. Other than adding additional fields, changes cannot be made that would alter result objects (ResultsMessage, ParameterInfo, PlanNode, etc.).  If extensive changes are needed, then the server api will need to be changed to have additional DQP methods that return different results.  The older method signatures will still be left in place though for older clients.

> Forward and Backward Compatibility of MetaMatrix JDBC Driver
> ------------------------------------------------------------
>
>                 Key: TEIID-207
>                 URL: https://jira.jboss.org/jira/browse/TEIID-207
>             Project: Teiid
>          Issue Type: Feature Request
>          Components: JDBC Driver
>    Affects Versions: 6.0.0
>            Reporter: Marc Shirley
>             Fix For: 7.0
>
>
> The MetaMatrix JDBC driver should be forward and backward compatible with newer/older versions of Enterprise Server.  It is understood that certain protocol changes may break the compatibility but this should only happen in major releases and not affect Service Packs and maintenance releases.

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