[DERBY-2114] Let Clock embed a HashMap rather than inherit from Hashtable

• Type: Improvement
• Status: Closed
• Priority: Trivial
• Resolution: Fixed
• Affects Version/s: 10.2.1.6
• Fix Version/s: 10.3.1.4
• Bug behavior facts: Performance
• Assignee: Dyre Tjeldvoll
• Reporter: Dyre Tjeldvoll
• Created: 23/Nov/06 13:31
• Updated: 29/Jun/09 14:22
• Resolved: 01/May/07 21:03

Description

Clock currently inherits from Hashtable, but the use of Hashtable is really an implementation detail that would benefit from being hidden as private member. All access to the hashtable happens inside sychronized blocks so it is safe to substitute a HashMap. This change appears to trigger a small increase in throughput, as measured by the average TPS number obtained by running the select client from DERBY-1961 repeatedly.