hast join - performance problem

grofaty · #1 (**permalink**) 12-12-03, 05:21

Hi,

I have performance problem with joining tables. With Visual Access Plan I have found out that tables are joined togeter with HASH JOIN type. I would like that DB2 uses only nested loop joins or merge joins.

Is it posible to set some DB2 setting to disable hash join?

My system: DB2 UDB 8.1 fp4 on Windows XP.

Thanks,
Grofaty

GertK · #2 (**permalink**) 12-12-03, 06:16

Quote:

Originally posted by grofaty
Hi,

I have performance problem with joining tables. I have found out that tables are joined togeter with HASH JOIN type. I would like that database uses only nested loop joins or merge joins. Is it posible to set some DB2 setting to disable hash join?

Thanks,
Grofaty

Hi,

You can disable hash joins with db2set DB2_HASH_JOIN=NO

regards, Gert

grofaty · #3 (**permalink**) 12-12-03, 07:07

Hi GertK,

This command works fine. Thanks.

Grofaty

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