[HIVE-18279] Incorrect condition in StatsOpimizer

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Invalid
• Fix Version/s: 3.2.0
• Component/s: Statistics
• Assignee: Oleksiy Sayankin
• Reporter: Oleksiy Sayankin
• Created: 14/Dec/17 16:14
• Updated: 23/Jul/18 11:47
• Resolved: 23/Jul/18 11:47

Description

At the moment StatsOpimizer has code

        if (rowCnt == null) {
          // if rowCnt < 1 than its either empty table or table on which stats are not
          //  computed We assume the worse and don't attempt to optimize.
          Logger.debug("Table doesn't have up to date stats " + tbl.getTableName());
          rowCnt = null;
        }

in method private Long getRowCnt(). Condition

if (rowCnt == null) {

should be changed to

if (rowCnt == null || rowCnt == 0) {

because 0 value also means that table stats may not be computed.

Issue Links

• is related to: HIVE-13452 StatsOptimizer should return no rows on empty table with group by
• links to: Review Board