Fixes for file renaming and manifest features

[NikhilCollooru]

== NO RELEASE NOTE ==

depended by https://github.com/facebookexternal/presto-facebook/pull/1363

[highker]

Yes correct. We append 0s in front.

If we append 0s for bucketed tables, why sorting will be a problem? Or even with bucketed tables + file renaming, we will not do 0 appending anymore?

[NikhilCollooru]

Yes correct. We append 0s in front.

If we append 0s for bucketed tables, why sorting will be a problem? Or even with bucketed tables + file renaming, we will not do 0 appending anymore?

In normal scenario, for bucketed tables the names are like "file_prefix + padded_bucket_number" .
https://github.com/prestodb/presto/blob/master/presto-hive/src/main/java/com/facebook/presto/hive/HiveWriterFactory.java#L635
The fileName is not efficiently compressable because of the file-prefix.

In file renaming case, we dont append 0 at the beginning of the filename because we dont know how many files are there in the partition . Hence we dont know how many 0s we should pad.