Hash join overflows

[Racerx]

Hi All,

I use db2 v8.1 on AIX 5L

Evrytikme I take a snapshot for one my databases I can see that there
are Hash join overflows and small hash join overflows..
Jus need to know what shud i look into yo solve the problem..

I also encounter sort overflows so I changed the SORTHEAP parameter to
512..
But that does not seem to help..

Regards,
Racerx...

[Phil Sherman]

Overflows occur when the volume of data to be sorted is larger than the
size of the (in memory) sort work area, which is adjusted by changing
the size of SORTHEAP. You can't make it large enough to do all sorts in
memory but try to adjust its size to strike a good balance between the
following:
1. Percentage of sorts that go into overflow
2. Total amount of storage available for sorting (SHEAPTHRES)

Figuring out the "best" settings for controlling sort memory usage is a
function of your workload and performance objectives and falls under the
generalized heading of "performance tuning".

Phil Sherman
Racerx wrote:

Hi All,

I use db2 v8.1 on AIX 5L

Evrytikme I take a snapshot for one my databases I can see that there
are Hash join overflows and small hash join overflows..
Jus need to know what shud i look into yo solve the problem..

I also encounter sort overflows so I changed the SORTHEAP parameter to
512..
But that does not seem to help..

Regards,
Racerx...