[CALCITE-393] If no fields are projected from a table, field trimmer should project a dummy expression

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.9.1-incubating
• Assignee: Julian Hyde
• Reporter: Julian Hyde
• Created: 29/Aug/14 19:55
• Updated: 18/Oct/14 22:36
• Resolved: 29/Aug/14 22:05

Description

If no fields are projected from a table, field trimmer should project a dummy expression. Projecting no expressions is wrong, because it confuses other parts of the system; projecting all fields is wrong, because we would get data volume stats wrong and lose the opportunity to read less data from disk.