The TBUFSIZE= option
defines the buffer for the SAS application layer. The TCPMSGLEN= option
defines another buffer for the SAS communications layer. For more
information about TCPMSGLEN=, which is used only by the TCP/IP communications
access method, see the topic that is appropriate to your operating
environment in
Communications Access Methods for SAS/CONNECT and SAS/SHARE.
Summary of Attributes for the TBUFSIZE= and TCPMSGLEN= Options
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SAS/CONNECT uses the
buffer to transfer data to the communications layer.
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The TCP/IP access method
uses the buffer to transfer data to a client or a server.
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The SAS application
layer does the following:
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packs and compresses
data records into a buffer until all the data has been processed or
the buffer is full.
-
sends a buffer to the
communications layer. Unless it is explicitly set using the TBUFSIZE=
or TCPMSGLEN= options, the default buffer size is determined by the
TCP stack on the host operating system.
SAS/CONNECT uses the default
TCP stack settings and auto tuning (if implemented on the stack) to
ensure optimal network performance.
Using the TBUFSIZE=
option to maximize buffer size for the SAS application layer reduces
the number of calls that the application layer makes to the communications
layer for a data transfer. A reduction of calls to the communications
layer saves resources and improves operating environment and network
performance. Other factors, such as the amount of data and the network
bandwidth, must be considered to optimize buffer performance.
The SAS communications
layer does the following:
-
receives a buffer from
the SAS application layer.
-
sends a buffer to the
client or to the server. Unless it is explicitly set using the TBUFSIZE=
or TCPMSGLEN= options, the default buffer size is determined by the
TCP stack on the host operating system.
SAS/CONNECT uses the default
TCP stack settings and auto tuning (if implemented on the stack) to
ensure optimal network performance.
As with the TBUFSIZE=
option, an optimal value assigned to TCPMSGLEN= can save resources
and improve network performance. TCPMSGLEN= can be set to transfer
the entire buffer it receives or to divide the data into multiple
transfers.
To change the size of
the TCP buffer, the TCPMSGLEN= option is specified at both the client
and the server. If the client and the server do not use identical
values for TCPMSGLEN=, the smaller buffer size is used.
In addition to being
a system option, TBUFSIZE= can be set as an option in the SIGNON statement.
The option in the SIGNON statement or command takes precedence over
the system option.
CAUTION:
Do not
specify the TBUFSIZE= option in the server session. Specify the TBUFSIZE=
Option in the Client Session Only
If you specify the TBUFSIZE=
option in a remote SAS invocation that runs an AUTOEXEC file, the
allocated buffers might be insufficient to complete the processing
of the AUTOEXEC file. Although the client can successfully sign on
to the server session, the error message that would alert you to insufficient
buffers might not be written to the server log immediately. Instead,
the error message would be logged following the client's next request
for server processing.
Specify the TBUFSIZE=
option in the SIGNON statement in the client session when signing
on the server session.