[
https://issues.apache.org/jira/browse/AVRO-557?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12895855#action_12895855
]
Doug Cutting commented on AVRO-557:
-----------------------------------
> hashes on schemas are expensive. (I did separately push for schema's to be
> immutable so that their hashcodes could be memoized, but that hasn't been
> done yet).
Schema's are mostly immutable. You can add properties, and there's
setFields(), which is called once during the construction of a record. In the
latter case, it's an error to use the schema in any way before setFields() has
been called. In the former, we could reset the memoized hashCode whenever a
property is added. So I think we could reasonably memoize Schema#hashCode(),
and it could be a good performance win.
But perhaps we shouldn't call hashCode() anyway, but instead use an identity
map. If we used Google collections we could have a weak, identity cache of the
form Map<Schema,Map<Schema,Resolver>>. If someone adds a property to the
schema after its used that changed what the resolver does then they'd have
trouble, but (a) they shouldn't do that; and (b) the resolver doesn't currently
use any user-defined schema properties anyway, and I don't expect it ever will.
Would identity work for your use cases, Kevin? Do you have a table of schemas
somewhere, or are you parsing them anew each time?
> Speed up one-time data decoding
> -------------------------------
>
> Key: AVRO-557
> URL: https://issues.apache.org/jira/browse/AVRO-557
> Project: Avro
> Issue Type: Improvement
> Components: java
> Affects Versions: 1.3.2
> Reporter: Kevin Oliver
> Assignee: Kevin Oliver
> Fix For: 1.4.0
>
> Attachments: AVRO-557.patch
>
>
> There are big gains to be had in performance when using a BinaryDecoder and a
> GenericDatumReader just one time. This is due to the relatively expensive
> parsing and initialization that came with 1.3. Patch with example code and a
> Perf harness to follow.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
