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https://issues.apache.org/jira/browse/DERBY-5980?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13632947#comment-13632947
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Mike Matrigali commented on DERBY-5980:
---------------------------------------

posting an exact repro case would make it more likely the community would help 
with this.  It helps to make sure
what you are seeing is what others are seeing.  For instance there is a big 
difference between 10-20 MB of 1 byte
inserts vs 1 20 mb blob insert.
                
> Extremely slow roll forward when booting database that wasn't properly closed
> -----------------------------------------------------------------------------
>
>                 Key: DERBY-5980
>                 URL: https://issues.apache.org/jira/browse/DERBY-5980
>             Project: Derby
>          Issue Type: Bug
>    Affects Versions: 10.9.1.0
>         Environment: Windows 7, Embedded mode
>            Reporter: Igor Sereda
>
> 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.

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