hive-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Jeff Hammerbacher (JIRA)" <>
Subject [jira] Commented: (HIVE-207) Change SerDe API to allow skipping unused columns
Date Tue, 06 Jan 2009 23:49:44 GMT


Jeff Hammerbacher commented on HIVE-207:

I learned a lot, too. Could someone with a handle on Hive compress this discussion into reusable
documentation and post it to the Hive site?

> Change SerDe API to allow skipping unused columns
> -------------------------------------------------
>                 Key: HIVE-207
>                 URL:
>             Project: Hadoop Hive
>          Issue Type: Bug
>          Components: Query Processor, Serializers/Deserializers
>            Reporter: David Phillips
> A deserializer shouldn't have to deserialize columns that are never used by the query
processor.  A serializer shouldn't have to examine unused columns that are known to always
be null.
> As an example, we store data as a Protocol Buffer structure with ~60 fields.  Running
a "select count(1)" currently requires deserializing all fields, which includes checking if
they exist and formatting the data appropriately.  This is expensive and unnecessary.

This message is automatically generated by JIRA.
You can reply to this email to add a comment to the issue online.

View raw message