Gavin

[Feature] Add a case sensitive flag to hdfs scan node to indicate whether the hive table column names are case sensitive or not

4

## What type of PR is this： - [ ] bug - [x] feature - [ ] enhancement - [ ] refactor - [ ] others ## Which issues of...

[Feature] Add a block cache module to improve external table query performance

1

## What type of PR is this： - [ ] BugFix - [x] Feature - [ ] Enhancement - [ ] Refactor - [ ] UT - [ ] Doc...

[WIP] Support evicting old cache items with a given probability option to avoid frequent cache replacement.

2

## Why I'm doing: Sometimes when the datacache quota is smaller than the query io bytes, evict the old cache item and populate a new one may cause too much...