[PHOENIX-4674] Incorrect stats if data size is less than guidepost width

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Not A Problem
• Assignee: Abhishek Singh Chouhan
• Reporter: Abhishek Singh Chouhan
• Created: 27/Mar/18 13:06
• Updated: 30/Apr/18 23:41
• Resolved: 30/Apr/18 23:41

Description

For a small table, lets say with a single region < guidepost width, the stats after running update statistics can be way off. This is because we get an empty guidepost for the region and in BaseResultIterators we end up estimating the #rows as guidepostwidth/estimated row size of the table. For a table having <100 rows and guidepost width size of 100 mb, if the estimated row size is 100 bytes we end up estimating a million rows.