[HIVE-21955] SearchArgumentImpl generates wrong ExpressionTree in some cases which might result in loss of data

• Type: Bug
• Status: Patch Available
• Priority: Critical
• Resolution: Unresolved
• Affects Version/s: 1.2.1
• Component/s: Hive, storage-api
• Labels: pushdown
• Target Version/s: 1.2.1
• Assignee: Zihao Ye
• Reporter: Zihao Ye
• Created: 04/Jul/19 07:22
• Updated: 09/Jul/19 06:25

Description

ExpressionBuilder applies `pushDownNot`, `foldMaybe`, `flatten`, `convertToCNF`, `flatten` and `buildLeafList` in order to form a non-normalized expression into a CNF expression with the unique leaves.

After an expression is converted to CNF, there might be more than one non-leaf nodes which are exactly the same object in the expression tree. If this happens, those non-leaf nodes will be visited more than once in `buildLeafList` function. As a result, a wrong ExpressionTree is generated.

My version is 1.2.1, but it seems that the higher versions are also affected