Todd Lipcon created KUDU-1600:
---------------------------------
Summary: Disallow enabling compression on already-compressed
encodings
Key: KUDU-1600
URL: https://issues.apache.org/jira/browse/KUDU-1600
Project: Kudu
Issue Type: Bug
Components: cfile, master, perf
Reporter: Todd Lipcon
Some encodings (eg bitshuffle) are already compressed with LZ4, and enabling
another pass of LZ4 compression on top of it just burns CPU. We should disallow
such pairs of encodings.
This is slightly trickier in the case of something like dictionary encoding,
since it has the fallback path. For blocks that have fallen back to plain
encoding, LZ4 is a good idea, whereas for blocks that are dict-encoded, the
code words are already compressed and LZ4 is a waste.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
