Kbase P121969: How to calculate the optimal -pica setting for OpenEdge Replication
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
3/21/2008 |
|
Status: Verified
GOAL:
How to calculate the optimal -pica setting for OpenEdge Replication
GOAL:
What is ?pica Used For?
FACT(s) (Environment):
All Supported Operating Systems
Fathom Replication
OpenEdge Replication
FIX:
The ?pica argument is used to specify the amount of storage in Kbytes allocated for inter-process communications between RDBMS processes. The communications area allocated is utilized to send "messages" from one RDBMS process to another; for example, from the RDBMS to the Replication Server. A finite number of IPC message can fit into the memory allocated by setting ?pica and the number of message varies by version. The minimum value for ?pica is 4. The maximum value for ?pica varies by version. OpenEdge Replication uses the ?pica queue.
Calculating ?pica for Replication
The following information should be used to estimate the amount of ?pica that will be required for OpenEdge Replication to run optimally.
The data is gathered from the following location:
1) Start promon
2) Choose R&D Menu
3) Choose Option 2 - Activity Displays
4) Choose Option 6 ? AI Log
5) Capture Total AI Writes for the busiest period. Sampling information can be done in 2 formats. The first is to capture the total AI writes for the complete time. For example, if the busy period lasts 1 hour then capture a sample for the complete hour. The second is to capture smaller samples within the busy time. For example, if the busy period lasts 1 hour capture a 10 minute sample at the beginning, middle, and end of the busy period. Add these values up for the appropriate number. The first method is the preferred method.
6) Once this information is captured then apply the following formula:
TAIW ? Total AI Writes
BlockCount ? Block count for OpenEdge Version (Version 9 = 18.2, Release 10 ? 9.16)
-pica = (TAIW / BlockCount) * 1.25
Sample Table
TAIW Value
OpenEdge Version
Block Count
Multiplier
-pica Setting
5,000
10
9.16
1.25
682
20,000
10
9.16
1.25
2,729
100,000
10
9.16
1.25
8,192*
5,000
9
18.2
1.25>
343
20,000
9
18.2
1.25
1,374
100,000
9
18.2
1.25
6,868
* - Actual value is 13,646. Maximum value of ?pica is currently 8192.
NOTE: This formula does not take into account the Replication server removing blocks from the queue during the process. This would lower the actual value required. This information is not available at this time..