Hello

I defined a blob field and set the compression level to optimal.
Then I load a jpeg image into the fiels and save it after
and the jpeg file size remain exactly the same.

What the compression level does?

Thanks Sorin

Hershcu


It will compress whatever is in the field, however, jpegs are already pretty well compressed so ElevateDB won't be able to do anything. Try it with a bitmap that should show you something happening.

Roy Lambert [Team Elevate]

> It will compress whatever is in the field, however, jpegs are already
> pretty well compressed so ElevateDB won't be able to do anything. Try it
> with a bitmap that should show you something happening.
>
> Roy Lambert [Team Elevate]
>

I try with a bmp file and it also remain the same size and exactly the same

Sorin

Hershcu


>I try with a bmp file and it also remain the same size and exactly the same

What size bitmap and what is the blob block size? Also what are you measuring - can you quote some figures?

Roy Lambert [Team Elevate]

> What size bitmap and what is the blob block size? Also what are you
> measuring - can you quote some figures?
>
> Roy Lambert [Team Elevate]

The original bmp file is 11,655 KB
On the Table after loaded the ElevateDB Manager show 11934054 bytes
After SaveToFile from the table again 11,655KB

Thanks Sorin

Hershcu

>The original bmp file is 11,655 KB

>After SaveToFile from the table again 11,655KB

I'd certainly expect the actual file size to be the same after extracting from the table and saving to file. If it weren't I'd be really worried as you would no longer be able to display it. IE the compression is only for storage in the ElevateDB table. Its compressed as it goes in and decompressed when it comes out.

>On the Table after loaded the ElevateDB Manager show 11934054 bytes

Where are you getting this from? I don't know anywhere in EDBManager that shows table size (but I'm always prepared to learn). However, you may be missing something. If you've already stored an uncompressible image in the table that space will not be freed until you OPTIMIZE the table.

Roy Lambert [Team Elevate]

"Roy Lambert" <roy.lambert@skynet.co.uk> wrote in message
news:95D25BD6-DE6B-44F1-8760-09C69DBCDB6A@news.elevatesoft.com...
> Hershcu
>
>>The original bmp file is 11,655 KB
>
>>After SaveToFile from the table again 11,655KB
>
> I'd certainly expect the actual file size to be the same after extracting
> from the table and saving to file. If it weren't I'd be really worried as
> you would no longer be able to display it. IE the compression is only for
> storage in the ElevateDB table. Its compressed as it goes in and
> decompressed when it comes out.
>
>>On the Table after loaded the ElevateDB Manager show 11934054 bytes
>
> Where are you getting this from? I don't know anywhere in EDBManager that
> shows table size (but I'm always prepared to learn).

When I open the table with the EDB Manager, on the columns of the blob
field. It show the bytes size of each blob field record.

>However, you may be missing something. If you've already stored an
>uncompressible image in the table that space will not be freed until you
> OPTIMIZE the table.
>
> Roy Lambert [Team Elevate]

No, the blob field was defined as compressed from the begining

Thanks Sorin

Hello

I make a diferent test
I start from an empty table, then append 3 new records with a blob field.

On each blob field I load a   .Tif  file 1318KB size.
Then I check the size of .EDBBlb file and it show 3750KB.

So where is the compression?

Thanks Sorin

"Hershcu S"
> Hello
>
> I make a diferent test
> I start from an empty table, then append 3 new records with a blob field.
>
> On each blob field I load a   .Tif  file 1318KB size.
> Then I check the size of .EDBBlb file and it show 3750KB.
>
> So where is the compression?

Sorin,

You can't compress a file that is already compressed.
Generally, all image format files are compressed in the first place.
ex.
- jpg
- tif
-png
-gif

Examples on files that you can expect to compress are
- bmp
- txt
- rtf
- doc  (the old word format)
- xls  (the old excel format)
- all sorts of datafiles

--
Jan-Erik

Thanks

yes with bmp file I can see the compress

Sorin

"Jan-Erik Johansen" <jej at morpheus dot no> wrote in message
news:C8AFA86A-EB4A-4FD6-93E1-CE6EB44B750C@news.elevatesoft.com...
> "Hershcu S"
>> Hello
>>
>> I make a diferent test
>> I start from an empty table, then append 3 new records with a blob field.
>>
>> On each blob field I load a   .Tif  file 1318KB size.
>> Then I check the size of .EDBBlb file and it show 3750KB.
>>
>> So where is the compression?
>
> Sorin,
>
> You can't compress a file that is already compressed.
> Generally, all image format files are compressed in the first place.
> ex.
> - jpg
> - tif
> -png
> -gif
>
> Examples on files that you can expect to compress are
> - bmp
> - txt
> - rtf
> - doc  (the old word format)
> - xls  (the old excel format)
> - all sorts of datafiles
>
> --
> Jan-Erik
>