using dbt2 postgresql 8.4 - rampup time issue

Hi,

We are using dbt2 to check performance of postgresql 8.4 on Linux64 machine. When we increase "TERMINALS PER WAREHOUSE" TPM value increase rapidly but rampup time increase too , dbt2 estimated rampup time calculation do not work properly that’s why it run the test for wrong duration i.e.

1.
Settings :
DATABASE CONNECTIONS: 50
TERMINALS PER WAREHOUSE: 10
SCALE FACTOR (WAREHOUSES): 200
DURATION OF TEST (in sec): 7200
Result :
Response Time (s)
Transaction % Average : 90th % Total Rollbacks %
------------ ----- --------------------- ----------- --------------- -----
Delivery 3.96 0.285 : 0.023 26883 0 0.00
New Order 45.26 0.360 : 0.010 307335 3082 1.01
Order Status 3.98 0.238 : 0.003 27059 0 0.00
Payment 42.82 0.233 : 0.003 290802 0 0.00
Stock Level 3.97 0.245 : 0.002 26970 0 0.00
------------ ----- --------------------- ----------- --------------- -----

2508.36 new-order transactions per minute (NOTPM)
120.1 minute duration
0 total unknown errors
2000 second(s) ramping up

2.
Settings :
DATABASE CONNECTIONS: 50
TERMINALS PER WAREHOUSE: 40
SCALE FACTOR (WAREHOUSES): 200
DURATION OF TEST (in sec): 7200
Result :
Response Time (s)
Transaction % Average : 90th % Total Rollbacks %
------------ ----- --------------------- ----------- --------------- -----
Delivery 3.95 8.123 : 4.605 43672 0 0.00
New Order 45.19 12.205 : 2.563 499356 4933 1.00
Order Status 4.00 7.385 : 3.314 44175 0 0.00
Payment 42.89 7.221 : 1.920 473912 0 0.00
Stock Level 3.97 7.093 : 1.887 43868 0 0.00
------------ ----- --------------------- ----------- --------------- -----

7009.40 new-order transactions per minute (NOTPM)
69.8 minute duration
0 total unknown errors
8016 second(s) ramping up
3.
Settings :
DATABASE CONNECTIONS: 50
TERMINALS PER WAREHOUSE: 40
SCALE FACTOR (WAREHOUSES): 200
DURATION OF TEST (in sec): 7200
Result :
Response Time (s)
Transaction % Average : 90th % Total Rollbacks %
------------ ----- --------------------- ----------- --------------- -----
Delivery 3.98 9.095 : 16.103 15234 0 0.00
New Order 45.33 7.896 : 14.794 173539 1661 0.97
Order Status 3.96 8.165 : 13.989 15156 0 0.00
Payment 42.76 7.295 : 12.470 163726 0 0.00
Stock Level 3.97 7.198 : 12.520 15198 0 0.00
------------ ----- --------------------- ----------- --------------- -----

10432.09 new-order transactions per minute (NOTPM)
16.3 minute duration
0 total unknown errors
11227 second(s) ramping up

These results show that dbt2 test actually did not run for 2 hours but it start varying with the increase of "TERMINALS PER WAREHOUSE" value i.e. 1st Run ( 120.1 minute duration ), 2nd Run (69.8 minute duration) and 3rd Run (16.3 minute duration).

To fix and sync with the rampup time, I have made a minor change in the dbt2-run-workload script i.e.

--- dbt2-run-workload 2010-07-02 08:18:06.000000000 -0400
+++ dbt2-run-workload 2010-07-02 08:20:11.000000000 -0400
@@ -625,7 +625,11 @@
done

echo -n "estimated rampup time: "
-do_sleep $SLEEP_RAMPUP
+#do_sleep $SLEEP_RAMPUP
+while ! grep START ${DRIVER_OUTPUT_DIR}/*/mix.log ; do
+ sleep 1
+done
+date
echo "estimated rampup time has elapsed"

# Clear the readprofile data after the driver ramps up.

What is rempup time ? And what do you think about the patch?. Can you please guide me?. Thanks.

Best Regards,
Asif Naeem

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