Subject Odp: [firebird-support] Request for advice
Author liviuslivius@poczta.onet.pl
Hi,

But you also misunderstud advice.
Blobs are not stored in table with its other fields. In record exists only blob id and blob is stored on separate pages. Then moving it to separate table do nothing.


But i always prefere store big data like document scans outside of database and in main database have only some hint about file name without final location.

Only application have knowlage about final location and can load document

Regards,
Karol Bieniaszewski

----- Reply message -----
Od: "Thomas Beckmann" <thomas.beckmann@...>
Do: <firebird-support@yahoogroups.com>
Temat: [firebird-support] Request for advice
Data: pt., kwi 25, 2014 00:46


 

As I fear, some people misunderstood Frank's hints, I'd like to clarify:
I know no reason to store blobs in data table with other objects data,
it should be stored in separate table(s).

This does not (significantly) grow database, does not make it
significantly slower and does not have any impact on backup/restore: But
performs ways better, if blob fields are not main data fields.

This "optimization" has completely different impacts than moving blob
data to a different database: Not only that every select has to be
evaluated on runtime by execute statement, it has to be fetched from
"far" destination (with no optimization hints), and there are no means
to keep referential integrity by database design between the two databases.

Thomas

Am 25.04.2014 00:29, schrieb Alexandre Benson Smith:

>
>
> Em 24/4/2014 17:08, Mark Rotteveel escreveu:
>> On 24-4-2014 20:49, Frank Schlottmann-Gödde wrote:
>>> As a compromise, I would suggest to place your blobs into a separate
>>> table, it will increase the size of your main database, but will also
>>> speed up the acccess to your blobs without interfering with everyday
>>> database operations.
>> As most blobs are stored out of band, I would expect that moving them to
>> a separate table this doesn't have a big impact unless you have the
>> habit of always retrieving and loading all fields of a table.
>>
>> Mark
>
> If the blob's are small enough to fit into the data page, it will
> dramatically reduce the number of records per page, and ever if you
> don't select it you will read the whole page, where most part of it is
> the blob content.
>
> Moving the blob to a separate table would reduce this.
>
> see you !
>
>

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