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Thread Blob usage for images
Thu, Mar 15 2007 6:20 PMPermanent Link

"JA Taylor"
We are about to start testing storing images in a DBISAM database.  Our
starting images are approx 600x400 pixels.  'Retrieval' speed  and 'minimum'
database size are what are most important to us.

What would be the recommended method for achieving this?

Would there be any significant speed etc advantage in using in migrating
ElevateDB?



Fri, Mar 16 2007 4:27 AMPermanent Link

Roy Lambert

NLH Associates

Team Elevate Team Elevate

JA


I store all sorts of things in blob fields (I use memo rather than blob) and I can say it works well.

To minimise the database size the blob fields to as near the size of the data as you can to the next 64 above. That should reduce wasteage. It should also help performance.

The only other thing I can think of ti help performance is to only call for the image when its needed, or if you're displaying a picture as users scroll through a database then use a timer or event to load it AFTER scrolling has stopped.

Roy Lambert
Fri, Mar 16 2007 3:46 PMPermanent Link

Tim Young [Elevate Software]

Elevate Software, Inc.

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Email timyoung@elevatesoft.com


<< We are about to start testing storing images in a DBISAM database.  Our
starting images are approx 600x400 pixels.  'Retrieval' speed  and 'minimum'
database size are what are most important to us.

What would be the recommended method for achieving this? >>

Are the images compressed at all (JPEG, PNG, etc.) ?

<< Would there be any significant speed etc advantage in using in migrating
ElevateDB? >>

ElevateDB is faster with respect to BLOBs in two areas - deleting rows with
BLOBs/re-using the deleted space and retrieving/caching BLOBs using a remote
session with C/S access.

--
Tim Young
Elevate Software
www.elevatesoft.com

Fri, Mar 16 2007 6:12 PMPermanent Link

"JA Taylor"
> << We are about to start testing storing images in a DBISAM database.  Our
> starting images are approx 600x400 pixels.  'Retrieval' speed  and
> 'minimum' database size are what are most important to us.
>
> What would be the recommended method for achieving this? >>
>
> Are the images compressed at all (JPEG, PNG, etc.) ?
>
> << Would there be any significant speed etc advantage in using in
> migrating ElevateDB? >>
>
> ElevateDB is faster with respect to BLOBs in two areas - deleting rows
> with BLOBs/re-using the deleted space and retrieving/caching BLOBs using a
> remote session with C/S access.
>
> --
> Tim Young
> Elevate Software
> www.elevatesoft.com

The images are mixed types, however most would be JPG. (Our program would
mostly be used as a photo viewer)

The images need to be compressed in some form to achieve a reasonably sized
database.  Approx image size:   600x400 pixels

What would be the best format to store the data in to achieve the best
combination between the smallest database footprint and fastest retrieval
speed.

Thanks for any pointers.

Jim

Mon, Mar 19 2007 5:31 PMPermanent Link

Tim Young [Elevate Software]

Elevate Software, Inc.

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Email timyoung@elevatesoft.com

Jim,

<< What would be the best format to store the data in to achieve the best
combination between the smallest database footprint and fastest retrieval
speed. >>

Well, you can store the images in any format (compressed or not).  If you
choose to store them in an un-compressed format, then you should definitely
turn on BLOB compression for the BLOB field that you're using when you
create the table.

Also, for those size images, you should probably use a BLOB block size for
the table of around 2048-4096 bytes.  I certainly wouldn't go any lower than
that (the default is 512 bytes).

--
Tim Young
Elevate Software
www.elevatesoft.com

Image