[DERBY-5980] Extremely slow roll forward when booting database that wasn't properly closed

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 10.9.1.0
• Component/s: Store
• Labels: derby_triage10_12
• Environment: Windows 7, Embedded mode
• Urgency: Normal
• Bug behavior facts: Performance
• Assignee: Unassigned
• Reporter: Igor Sereda
• Created: 04/Nov/12 10:28
• Updated: 02/Mar/19 19:56

Description

Reproduction sequence:
1. Open database in embedded mode
2. Run a considerably large transaction - for example, one that creates 10 - 20 MB of db logs
3. Commit
4. Do NOT close the Connection
5. Exit the application (through System.exit() for example)
6. Restart the application and open the database

Observed:
Opening connection is extremely slow. It takes up 30- 60 seconds on the 10-20 MB transaction, and for larger transactions it takes forever.

Looking at the process with FileMon utility, I can see that redo log files are mostly read 1 byte at a time.
I bet you can improve the performance 100-fold by getting the whole log into memory first.