Re: Issue with SQL Server 2005 Mobile and SD Cards?
- From: adulador <msmolinski@xxxxxxxxx>
- Date: Fri, 21 Sep 2007 11:45:33 -0000
On Sep 20, 4:07 am, "Peter Hartlén" <pe...@xxxxxxx> wrote:
Hi!
I'd say there is no perfect solution using database on SD-card, and many
people would strongly advice against it.
There are several factors that help making life easier though if you for
some reason must have your db on an external disk.
1. Make sure the device has good drivers for the SD-card. We had several
problems with this in the beginning, but our device manufacturer eventually
solved this. Problems tend to arise when the device power-ups, the
application targetting the db is running, and the card drivers problably
doesn't initialize the card fast enough.
2. Make sure you use professional cards. Cards are so cheap nowadays anyway.
We've been using SanDisk Ultra II cards quite successfully. Older/Slower
cards has shown more tendency to malfunction. As your file system seems
corrupted from time to time I sugges trying this solution first.
Anyhow, if you are targeting WM5 or later I suggest putting the SD-card on
device memory instead. IIRC WM5 has some kind of data recovery handling, so
the database should be pretty safe (I'm not 100% sure on this).
/ Peter
"adulador" <msmolin...@xxxxxxxxx> skrev i meddelandetnews:1190232761.639342.282430@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Our application uses a database on an SD Card. We encounter strange
errors sometimes when we attempt to access it.
The errors are: 0x80004005, Description: Unspecified error; Minor = 0.
Once this occurs it never can recover. A soft reset sometimes solves
it, but not reliably.
Another observation is that after this error occurs, if you look at
the SD card in File Explorer, the file listing looks all messed up.
for example some folder and file names are,
========
Meta(====
nt="Robo.HEL
}boxboxol.wh
the file sizes are wacked out too. One said 1.58G and the card is only
512 MB.
The file system has gone corrupt or something.
Is there an issue with SQL Server 2005 Mobile and SD Cards?
Is there a setting i need to use when the DB is on an SD Card?
Environment Info:
DB: Sql Server 2005 Mobile Edition
in OLEDB C++.- Hide quoted text -
- Show quoted text -
Peter, thank you for your response.
I have implemented a couple things as you have suggested.
1. We are experimenting with high quality cards. The ones reporting
the errors were, in fact, old and slow cards.
2. I detect a wake up of the device now and before accessing the DB
again after a wake up I tear down the old connection, check for the
existance of the SD card and db file and then create a new database
connection, if all is there.
3. When a failed query with an unknow error code is detected, I
attempt the query one more time after tearing down the old conneciton,
detecting the existance of the SD card and the db file and creating a
new connection, if all is well.
We are still waiting to see the results of the above changes, to see
if it cleared up the problem.
I am also starting to wonder if there are any settings in the DB that
could be tweaked to help an SD Card based database. One in particular
I am just starting to look at is the FLUSH INTERVAL. Do you have any
advice along these lines?
.
- References:
- Issue with SQL Server 2005 Mobile and SD Cards?
- From: adulador
- Re: Issue with SQL Server 2005 Mobile and SD Cards?
- From: Peter Hartlén
- Issue with SQL Server 2005 Mobile and SD Cards?
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