Summary information |
|
|---|---|
Default value |
2048 |
Range of values |
512– 65024 |
Status |
Static |
Display level |
Intermediate |
Required role |
System administrator |
Configuration groups |
Memory Use, Network Communication, User Environment |
default network packet size configures the default packet size for all Adaptive Server users. You can set default network packet size to any multiple of 512 bytes; values that are not even multiples of 512 are rounded down.
Memory for all users who log in with the default packet size is allocated from the Adaptive Server memory pool, as set with total logical memory. This memory is allocated for network packets when Adaptive Server is started.
Each Adaptive Server user connection uses:
One read buffer
One buffer for messages
One write buffer
Each of these buffers requires default network packet size bytes. The total amount of memory allocated for network packets is:
(number of user connections + number of worker processes) * 3 * default network packet size
For example, if you set default network packet size to 1024 bytes, and you have 50 user connections and 20 worker processes, the amount of network memory required is:
(50 + 20) * 3 * 1024 = 215040 bytes
If you increase default network packet size, you must also increase max network packet size to at least the same size. If the value of max network packet size is greater than the value of default network packet size, increase the value of additional network memory. See “additional network memory”.
Use sp_sysmon to see how changing the default network packet size parameter affects network I/O management and task switching. For example, try increasing default network packet size and then checking sp_sysmon output to see how this affects bcp for large batches. See the Performance and Tuning Series: Monitoring Adaptive Server with sp_sysmon.
Clients automatically use the Adaptive Server default packet size. Use the -A flag to Adaptive Server client programs to request a large packet size. For example:
isql -A2048
