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From "Suresh Thalamati (JIRA)" <derby-...@db.apache.org>
Subject [jira] Created: (DERBY-101) Limit on Number of log that can be created should be increased (current limit is 4194303)
Date Fri, 10 Dec 2004 00:22:09 GMT
Limit on Number of log that can be created should be increased (current limit is  4194303)

         Key: DERBY-101
         URL: http://nagoya.apache.org/jira/browse/DERBY-101
     Project: Derby
        Type: Improvement
  Components: Store  
    Reporter: Suresh Thalamati
 Assigned to: Suresh Thalamati 

Number of log files that can be generated on derby is limited to 2^22 -1 (4194303). Once this
linit is reached the insert/delete/update and reovery
may not work. I belive this limit could be hit in a very active system that does lot of inserts
and deletes. 

Just a approximate calculation how this limit could  be hit:
If we assume every 1 minute a 1MB (default log file size)log data is generated on a Derby
database. It will take just 291 days to hit the limit. 

419403 / (60 * 24) = ~291 days. 

291 days limit seems to be something a system that does lot of inserts/deletes can possibly

It might be good idea to bump this limit to 2^32 -1 (4294967295).
By following the above assumption of 1M log data per minute with this 
linit it will take 8171.55 years: 
4294967295 / (60 * 24)  = 2982616.17 days  (8171.55 years) 
I guess this is a resonable limit!! 

One workaround for this problem is to change the log file size to 10 MB or more, that will
reduce the chance of hittig this limit. 

Please refer to derby-96 before fixing this issue, LSN format might get changed as part of
derby-96 fixes. 

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