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Jeff Hammerbacher commented on AVRO-806: ---------------------------------------- > I think the advantage of a columnar format is to avoid touching data that's > not needed, and avoiding decompression is consistent with that. During the design of RCFile, the folks from Facebook found that packing a few columns together into a file made for better performance than putting a single column into the file. There's a trade-off between CPU consumed in deserialization and IO consumed in pulling the data off of disk. Avoiding decompressing columns that are not accessed seemed to be important for Hive performance. > add a column-major codec for data files > --------------------------------------- > > Key: AVRO-806 > URL: https://issues.apache.org/jira/browse/AVRO-806 > Project: Avro > Issue Type: New Feature > Components: java, spec > Reporter: Doug Cutting > Assignee: Doug Cutting > Attachments: AVRO-806-v2.patch, AVRO-806.patch, avro-file-columnar.pdf > > > Define a codec that, when a data file's schema is a record schema, writes > blocks within the file in column-major order. This would permit better > compression and also permit efficient skipping of fields that are not of > interest. -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira