.blb file not shrinking after deleting ALL entries

[Andrew Sinning]

Ruslan,

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

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.
  . 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.

Thanks.


-----Original Message-----
From: valentina-bounces at lists.macserve.net
[mailto:valentina-bounces at lists.macserve.net]On Behalf Of Ruslan
Zasukhin
Sent: Sunday, February 15, 2004 2:00 PM
To: valentina at lists.macserve.net
Subject: Re: .blb file not shrinking after deleting ALL entries


on 2/15/04 9:59 PM, Andrew Sinning at andrew at learningware.com wrote:

> I asked about this last week, but didn't have time to follow up.
>
> I add 100 entries to a table.  The table has a single BLOB field.  My
> .blb file grows to 3.5Mb.
>
> Now, I execute 2 queries:
>
> DELETE FROM testTable
> COMPACT  (I also tried "COMPACT DATABASE" at Ruslan's suggestion)
>
>
> The size of the .blb file is STILL 3.5Mb.
>
> If I test the number of records in testTable, I get 0.

Strange.

COMPACT should move it down.

You can use XML dump then to get smaller db.

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

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