.blb file not shrinking after deleting ALL entries

[Ruslan Zasukhin]

on 2/15/04 11:02 PM, Andrew Sinning at andrew at learningware.com wrote:

Hi Andrew,

> Hi.  Didn't expect an answer on a Sunday.  Thanks!
> 
> I have added to my BLOB creation a COMPRESSED property:
> 
> vList BLOB NOT NULL COMPRESSED
> 
> with quite unbelievable results.  The read/write speeds are still 5
> times faster than using the vList xtra method of saving to a file (10
> times faster without comression), only now instead of being 2X the size
> of the vList files, the Valentina .blb containing 100 records is 1/7th
> the size of 100 vList files!
> 
> I have two questions about compression:
> 
> 1)  What kind of compression is used?

ZIP

> Is each individual blob field
> compressed, or is there some kind of compression going on over the
> entire table (by comparing entries?)

Each BLOB field.

Even More correctly. Each separate BLOB value.

> Here is my concern:  will the
> amount of time required to read/write an individual record grow if I
> have 10000 records, 100000 records, 1000000 records?

NO.


> 2) The docs state:  Valentina allows you compress a BLOB field. You can
> make a BLOB field compressed as easy as set its flag 'Compressed' to
> TRUE.

> . On default Valentina uses ZIP compression.

yes

> . You can set up level of compression in range 0..9.
>   0 - fastest compression.
>   9 - best compression.
> BUT, I don't see anywhere HOW to change the level of comression.

V4MD ?

It seems no way.

I need check why in V4MD this is not opened.

-- 
Best regards,
Ruslan Zasukhin      [ I feel the need...the need for speed ]
-------------------------------------------------------------
e-mail: ruslan at paradigmasoft.com
web: http://www.paradigmasoft.com

To subscribe to the Valentina mail list go to:
http://lists.macserve.net/mailman/listinfo/valentina
-------------------------------------------------------------