%META:TOPICPARENT{name="InstallConfigODBC"}% =[Communications] attributes on Multi-Tier client and server= Settings in the [Communications] stanza of the OpenLink Rulebook (oplrqb.ini) correspond roughly to settings in the [Communications] stanza of the odbc.ini file on Unix, Linux, and Mac OS X; the OpenLink Preferences PPC file on Mac OS 9; and the Windows Registry key section HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\OPENLINK.INI\Communications. These settings apply only to OpenLink Multi-Tier connections, and have no effect on OpenLink Single-Tier connections. On Unix, Linux, and Mac OS X, the best way to adjust these settings is through the HTTP-based OpenLink ODBC Administrator or Request Broker Admin Assistant. On Windows, the OpenLink Client Configuration Utility (oplcfg32.exe) is best used. Mac OS 9 users have the OpenLink Generic ODBC PPC control panel for this purpose. Please read the table below carefully before adjusting these settings from their defaults. OpenLink has set default values which are optimal for most situations, and adjusting these values without understanding them can disrupt data access.
Attribute Name Client Side
HKEY_LOCAL_MACHINE\SOFTWARE\ODBC\OPENLINK.INI,
ODBC Preferences PPC,
odbc.ini, or $ODBCINI
Server Side
Broker Rulebook
oplrqb.ini
SendSize The maximum message chunk size (in bytes) the OpenLink ODBC client will send to the Broker or Database Agent. This must match the Rulebook parameter ReceiveSize.

Shown as the Send buffer size in the HTTP-based configuration tools.

Default is 4096.
The maximum message chunk size (in bytes) the Broker or Database Agent will send to the client. This must match the client parameter ReceiveSize.

Shown as the Send buffer size in the HTTP-based configuration tools.

Default is 16000.
ReceiveSize The maximum message chunk size (in bytes) the OpenLink ODBC client will accept. This must match the Rulebook parameter SendSize.

Shown as the Receive buffer size in the HTTP-based configuration tools.

Default is 16000.
The maximum message chunk size (in bytes) the Broker or Database Agent will accept. This must match the client parameter SendSize.

Shown as the Receive buffer size in the HTTP-based configuration tools.

Default is 4096.
BrokerTimeout The number of seconds the client driver will wait for a response from the Request Broker, before timing out. 60 (one minute) is usually more than sufficient.

Shown as the Broker contact timeout in the HTTP-based configuration tools.

Default is 30.
The number of seconds local OpenLink executables which communicate directly with the Request Broker (e.g., oplshut) will wait for a response, before timing out. Again, 60 (one minute) should be sufficient.

Shown as the Broker contact timeout in the HTTP-based configuration tools.

Default is 30.
ReceiveTimeout The number of seconds the client driver will wait for the first results of a query. This should generally be set 10-25% longer than the anticipated DBMS execution time of the longest SQL query. It is not generally recommended that this parameter exceed 3600 (one hour), unless SQL queries are known to take longer.

Shown as the Agent contact timeout in the HTTP-based configuration tools.

Default is 120.
The number of seconds the Broker will wait for an initial response from a Database Agent, when starting a new connection, before the Broker launches a new instance of that Agent. This does not apply when you have the Agent Reuse value set to Never. It is not recommended this value be less than 10, and it should never be more than half of that Rulebook's BrokerTimeout.

Shown as the Agent initialization timeout in the HTTP-based configuration tools.

Default is 10.
RetryTimeout The number of seconds the ODBC client will wait before re-attempting a timed-out call to the server, either Broker or Agent. After each timeout, this value is doubled, with a maximum equal to the client's BrokerTimeout during initial connection establishment, and equal to the client's ReceiveTimeout during an active session. An initial setting of 5 is generally recommended.

Shown as the Agent retry timeout in the HTTP-based configuration tools.

Default is 5.
The number of seconds the Broker will wait before re-attempting to contact a Database Agent which has failed to respond. After each timeout, this value is doubled, with a maximum of 30. An initial setting of 5 is generally recommended.

Shown as the Client retry timeout in the HTTP-based configuration tools.

Default is 5.