Database Blobs & Performance

Basel Al-Khateeb

Hi geniuses,

I have a core database question in MS Access and SQL Server.

Assume the following table in MS Access or SQL Server:

Employees table:

EmpID, Name, Hiredate, Photo;

and the following query:

"SELECT EmpID, Name, Hiredate FROM Employees;"

The question is, "does the blob object (Photo) affect the performance of the query even when not included in the select statement "

I mean, will I gain some additional performance when separating the blob fields to another table

Thanks for the answer.

hrubesh

You should ask this question in the ms - sql forums,

From my point of view it should not, and i do not have an idea of the implementation of any of the ms databases till now,

anyone has related notes please direct on this, looks interesting.

Jens K. Suessmeyer

if you don¡¯t select the image / binary column there should be no performance issue.

Jens K. Suessmeyer.

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Arnie Rowland

Unless you have specifically created the table with the image/binary data 'in the row', it is NOT stored in the table.

sp_tableoption N'MyTable', 'large value types out of row', 'ON'

is the default. In the table, there is only a 'pointer' in the actual location.

In any case, NOT including the image/binary field in the SELECT statement will definintely enhance performance. But there will be little effect noticed by moving the image/binary pointer (16 bytes) to another table.