[
https://issues.apache.org/jira/browse/PIG-3015?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13510629#comment-13510629
]
Joseph Adler commented on PIG-3015:
-----------------------------------
Hi Johannes,
As you probably know, the Avro specification limits the set of valid characters
in names (see http://avro.apache.org/docs/current/spec.html#Names). Names must
- start with [A-Za-z_]
- subsequently contain only [A-Za-z0-9_]
So double colons aren't allowed. PIG-2684 proposes using namespaces as the
solution. I think that's a poor choice; namespaces are often used for other
purposes. Specifically, names spaces are essential if you are writing
complicated data processing software that processes multiple types of avro
serialized objects. In my experience, the avro schema and protocol compilers
produce much better, more usable code if you use name spaces.
There are two good workarounds:
- The Pig user can rename variables in a bag before storing the bag using
AvroStorage
- The Pig user can manually specify the output schema before storing the bag
with AvroStorage
So, here's a specific suggestion:
- By default, throw an exception if the pig schema contains a name with a
double-colon and the user does not specify an output schema
- Add an option to AvroStorage to transform double colons to something else.
(Maybe double underscores? Maybe storing them in the namespace?)
What do you think?
> Rewrite of AvroStorage
> ----------------------
>
> Key: PIG-3015
> URL: https://issues.apache.org/jira/browse/PIG-3015
> Project: Pig
> Issue Type: Improvement
> Components: piggybank
> Reporter: Joseph Adler
> Assignee: Joseph Adler
> Attachments: PIG-3015.patch
>
>
> The current AvroStorage implementation has a lot of issues: it requires old
> versions of Avro, it copies data much more than needed, and it's verbose and
> complicated. (One pet peeve of mine is that old versions of Avro don't
> support Snappy compression.)
> I rewrote AvroStorage from scratch to fix these issues. In early tests, the
> new implementation is significantly faster, and the code is a lot simpler.
> Rewriting AvroStorage also enabled me to implement support for Trevni.
> I'm opening this ticket to facilitate discussion while I figure out the best
> way to contribute the changes back to Apache.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
