Remove WiredTiger raw compression support:
- There is no longer any customer use of raw compression,
- As of the 3.6 release raw compression cannot be used with the lookaside table, making it useless for many workloads (see
- The raw compression code is relatively complex and brittle.
The changes in
WT-3968 (to make compression more adaptive to run-time compression results), partly overlaps with raw compression – raw compression maximizes compression results which is less important if standard compression adapts to do better compression. However, raw compression also allowed targeting fixed I/O sizes, which is potentially useful functionality we'd be getting rid of.