OS:linux
CPU 4
RAM 8G
DELL 6650+CX200

rows of the test table is 143715052

2 nodes in one db.

when i executed the command "select count(*)" , i used 'vmstat' to watch the performance. the CPU wait was 50 and the process blocks were 10.

****************
procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
1 2 6312 6540648 15600 959276 0 0 28 25 9 32 2 3 94 2
3 3 6312 6534528 15600 959276 0 0 148416 0 1485 1151 20 4 27 48
6 1 6312 6530896 15608 959268 0 0 162144 113 1524 1242 25 6 23 47
2 8 6312 6527816 15608 959268 0 0 174464 0 1541 1231 26 5 18 51
10 3 6312 6523840 15608 959268 0 0 172032 0 1543 1231 27 5 15 52
1 7 6312 6520120 15616 959260 0 0 176064 12 1554 1285 27 6 14 54
0 9 6312 6520048 15616 959260 0 0 154240 0 1499 1140 27 5 14 54
1 14 6312 6519912 15628 959248 0 0 173920 28 1539 1239 26 4 16 53
2 12 6312 6519200 15628 959248 0 0 182272 0 1565 1222 27 5 15 53
3 8 6312 6519144 15628 959248 0 0 159616 0 1512 1128 26 4 18 52
2 6 6312 6519072 15628 959248 0 0 166240 8 1522 1178 27 4 16 54
2 8 6312 6519072 15628 959248 0 0 165056 0 1506 1151 25 4 19 52
1 7 6312 6517864 15640 959236 0 0 132096 56 1420 1031 21 4 15 59

****************

how can i do?

pool english to express my ideas.

thanks.

CPU wait were nearly 50 and block progress were nearly 12, who can tell me how to turning the performance .
thanks a lot !!

Huyuhui,

it's very difficult to help you with the data you're giving. You just write you've issued "SELECT COUNT(*) ..."
I would start checking the system:
- how big are your bufferpools
- did you update the statistics for the table(s) involved?
- do you use different disks for logs and for data?
- and, and, and ...

Your design
- do you have an index defined? (DB2 can use it for count(*))
- how many containers did you define for your table? are these containers spread over many disks? how did you define prefetch
- and, and, and...

My suggestion: just google for "DB2 performance optimization", and you'll find lots of tips. Got some concrete question? post it here.

HTH