[ http://issues.apache.org/jira/browse/HADOOP-54?page=comments#action_12423560 ] Doug Cutting commented on HADOOP-54: ------------------------------------
I mostly have minor naming quibbles. The Writer method should be named just 'next', not 'nextRaw'. The new Writer subclasses should not be public, but rather should be created by a factory method. The RawValue class might better be named 'ValueBytes', and it's methods can simply be called writeCompressed(), writeUncompressed(), etc. Finally, a substantive remark: we should not allocate a new RawValue for each key read. So the new Reader methods should be: public ValueBytes createValueBytes(); public void next(DataOutputStream key, ValueBytes value); > SequenceFile should compress blocks, not individual entries > ----------------------------------------------------------- > > Key: HADOOP-54 > URL: http://issues.apache.org/jira/browse/HADOOP-54 > Project: Hadoop > Issue Type: Improvement > Components: io > Affects Versions: 0.2.0 > Reporter: Doug Cutting > Assigned To: Arun C Murthy > Fix For: 0.5.0 > > Attachments: VIntCompressionResults.txt > > > SequenceFile will optionally compress individual values. But both > compression and performance would be much better if sequences of keys and > values are compressed together. Sync marks should only be placed between > blocks. This will require some changes to MapFile too, so that all file > positions stored there are the positions of blocks, not entries within > blocks. Probably this can be accomplished by adding a > getBlockStartPosition() method to SequenceFile.Writer. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
