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From "Suresh Thalamati (JIRA)" <derby-...@db.apache.org>
Subject [jira] Resolved: (DERBY-101) Limit on Number of log that can be created should be increased (current limit is 4194303)
Date Fri, 27 May 2005 23:55:54 GMT
     [ http://issues.apache.org/jira/browse/DERBY-101?page=all ]
     
Suresh Thalamati resolved DERBY-101:
------------------------------------

     Resolution: Fixed
    Fix Version: 10.1.0.0

chages: r170686, 178486:
178486: This fix increases the maximum possible  log file number to  2^31 -1  and keeps the
 old limit of 2^22-1 on soft upgrade. 

170686: This patch was attempt to increase the max log file number to 2^33 -1 , but that fix
created  up grade problems because of  the  additional bits that are used from  the file position
field,  so the limit was reduced to
231-1 by r178486.


> Limit on Number of log that can be created should be increased (current limit is  4194303)
> ------------------------------------------------------------------------------------------
>
>          Key: DERBY-101
>          URL: http://issues.apache.org/jira/browse/DERBY-101
>      Project: Derby
>         Type: Improvement
>   Components: Store
>     Reporter: Suresh Thalamati
>     Assignee: Suresh Thalamati
>      Fix For: 10.1.0.0

>
> 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
hit.  
> 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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