[ADK-VNET 0004918]: Crash in Flush while adding large amount of Blob-data

[Ruslan Zasukhin]

On 30/5/10 2:32 PM, "Thomas Flemming" <tf at ttqv.com> wrote:

Hi Thomas,
 
> just to confirm, that I understood it correctly, specially in respect of
> disk-space-usage:
> 
>> http://www.valentina-db.com/bt/view.php?id=4918
>> Well, database segment size is 1024 bytes. And BLOB segment size is also 1024
>> bytes. You should understand the difference between db and blob segments.

First of all. Not sure if Ivan have point it in Mantis

** DEFAULT settings of
        db.SegmentSize  is 32KB
        blob.SegmentSize is 512 bytes it seems


* you going to have BIG dbs. Few GBs as we see.
  So no sense even try to reduce it.


> Assume I set database-blocksize to 8K.
> 
> Then I start filling up with blobs, which have in average a size of lets say
> 5K.
> 
> So vbd takes the first block (of 8k) and stores the first blob (of 5k).
> Whats happening with the remainig 3K if this block? Will it stay empty, or do
> you use it for the next blob?

Of course it will not be empty.

Just DO NOT try relate them! This is totally different and independent
things. Details you can read in WIKI / KERNEL section.

 
> Where comes the Blob-Blocksize in this game?

In your case you should not touch db.SegmentSize.
It must be 32Kb. 


And BLOB's segment size should be in ideal close to average size of your
BLOB data.

Note, that for one BLOB field this can be 512 bytes, for another 2KB, for
third 4KB...

Too BIG blog.segment size -- YES will give you some empty space in the LAST
segment of CHAIN of segment for each RECORD.


-- 
Best regards,

Ruslan Zasukhin
VP Engineering and New Technology
Paradigma Software, Inc

Valentina - Joining Worlds of Information
http://www.paradigmasoft.com

[I feel the need: the need for speed]