[CALCITE-987] Push limit 0 will result in an infinite loop

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.5.0
• Fix Version/s: 1.6.0
• Component/s: core
• Assignee: Pengcheng Xiong
• Reporter: Pengcheng Xiong
• Created: 22/Nov/15 09:52
• Updated: 21/Jan/16 22:20
• Resolved: 29/Nov/15 18:36

Description

We use "checkInputForCollationAndLimit" in RelMdUtil.java to check the input #rows. However, it calls RelMetadataQuery.getRowCount which will validate the #rows. The validation will change #row=0 to #row=1. This will result in an infinite loop to push limit. The affected rules include
SortUnionTransposeRule and any Sort***TransposeRules that call checkInputForCollationAndLimit.

Issue Links

• breaks: CALCITE-995 Sort transpose rules might fall in an infinite loop
• relates to: CALCITE-1018 SortJoinTransposeRule not firing due to getMaxRowCount(RelSubset) returning null