[FLINK-14159] flink rocksdb StreamCompressionDecorator not right

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Abandoned
• Affects Version/s: 1.9.0
• Component/s: Runtime / State Backends
• Labels: auto-deprioritized-major
• Assignee: Unassigned
• Reporter: Jacky Lau
• Created: 21/Sep/19 02:21
• Updated: 29/Sep/21 02:02
• Resolved: 29/Sep/21 02:02

Description

I think the current flink rocksdb StreamCompressionDecorator is not right when calling method 

getCompressionDecorator(executionConfig) ,which defalut value is false.That is to say, current compression is none.But I find rocksdb  using options.compression to specify the compression to use. By default it is Snappy, which you can see here https://github.com/facebook/rocksdb/wiki/RocksDB-Tuning-Guide. And I use rocksdb tool sstdump to find it is indeed snappy compression.

So I think it should be return SnappyStreamCompressionDecorator.INSTANCE  rather than getCompressionDecorator( executionConfig) 

Coud i commit a PR?