[DERBY-6335] Improve performance of FETCH NEXT/OFFSET with ORDER BY

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: SQL
• Assignee: Unassigned
• Reporter: Dag H. Wanvik
• Created: 05/Sep/13 13:43
• Updated: 08/Oct/13 08:31

Description

We can utilize information about the number of rows to be retrieved to

a) optimize any sorting imposed by the ORDER BY by keeping only the top <next> rows in memory,
b) inform the optimizer with more precise information about the number of rows in those cases where such a constrict is a join participant.

For b) this would only work if <next> were known statically at compile time. For a) this could work even with ? parameters,

Issue Links

• relates to: DERBY-4675 OFFSET/FETCH SYNTAX EFFICIENCY