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From "Mike Matrigali (JIRA)" <derby-...@db.apache.org>
Subject [jira] Commented: (DERBY-465) Embedded Derby-PointBase comparison
Date Tue, 19 Jul 2005 18:50:48 GMT
    [ http://issues.apache.org/jira/browse/DERBY-465?page=comments#action_12316146 ] 

Mike Matrigali commented on DERBY-465:

It is very interesting that the other embedded db's don't seem to need indexing, again without
seeing the ddl
used for those db's it is hard to tell if somehow they may be automatically building an index.
 Is the natural
key of the table the 1st column in your table?  Are the results the same for the other db's
if you make it the
last column?

For your pointbase tests what value do you have for the pointbase log.forcewrite parameter.
 Here is their writeup
about the danger of not forcing log writes:
log.forcewrite false When log.forcewrite is false, a physical write to the log file on the
disk system will NOT be forced after each commit. It is left to the operating system to flush
the buffer onto the disk as per the operating system's schedule. If there is an abnormal termination
of the program, there is a possibility that some committed transactions will be lost. In some
cases the database may get corrupted. However, a forced write to the log file on the disk
WILL occur when the database is closed.

With log.forcewrite set to true, whenever there is hardware failure/system reset, the last
commit to the log file will be written before the failure. When log.forcewrite is true, every
time a commit is made (by manually committing or auto commit = true), a physical write to
the log file on the disk system will be FORCED. 

My interpretation of this is that by default pointbase does not correctly support crash recovery,
and probably should be marked so in your write up.

> Embedded Derby-PointBase comparison
> -----------------------------------
>          Key: DERBY-465
>          URL: http://issues.apache.org/jira/browse/DERBY-465
>      Project: Derby
>         Type: Wish
>   Components: Test
>     Versions:,
>  Environment: Windows Server 2003, 4 processors, summary CPU 3.00 Ghz, RAM 1 Gb
>     Reporter: Peter Kovgan
>  Attachments: Benchmarks_info_independent.doc, derby-optimization.doc
> I have tested 4 major embedded DB.
> I have found that major disadvantage of Derby is 
> 1)low insert speed and 
> 2)significant performance degradation in select, update, delete  operation speed starting
from some table size.
> PointBase in comparison has not such degradation.
> It will be better if you improve your product.
> Good luck and thank you.

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