Query with blob fields very slow

Discussion of open issues, suggestions and bugs regarding usage of dbExpress drivers for Oracle in Delphi and C++Builder
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chkaufmann
Posts: 69
Joined: Sat 01 Jul 2006 11:42

Query with blob fields very slow

Post by chkaufmann » Sat 01 Jul 2006 11:49

Hi,

I have a query with about 12'000 records. One column is a blob field, in my case with about 100-1500 bytes of data.
Reading of this query/column is very slow. The tools I use:

Oracle 9
dbExpress Driver 2.1
Delphi 6

When I profile the critical routine, most of the time is lost here:

blob := myQuery.CreateBlobStream('GEOMETRY', bmRead); >> 27%
...
blob.Free; >> 70%

My question is, how can I speed it up:
- configuration on Oracle server ?
- configuration on Oracle database / table / column ?
- settings in driver ?
- other technologie, e.g. Oracle direct instead of dbExpress?

cu Christian

Plash
Devart Team
Posts: 2844
Joined: Wed 10 May 2006 07:09

Post by Plash » Wed 05 Jul 2006 10:59

Performance will be improved greatly if you use ODAC instead of dbExpress.

chkaufmann
Posts: 69
Joined: Sat 01 Jul 2006 11:42

Post by chkaufmann » Wed 05 Jul 2006 11:24

plash wrote:Performance will be improved greatly if you use ODAC instead of dbExpress.
And there is no parameter, that has an influence on performance when using the CoreLab dbExpress driver?

cu Christian

Plash
Devart Team
Posts: 2844
Joined: Wed 10 May 2006 07:09

Post by Plash » Fri 07 Jul 2006 09:09

Core Lab dbExpress driver has no parameters that influence on performance when reading BLOB data.

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