What does the error message "cannot adjust socket SO_SNDBUF - exiting" signify? (4286422)

The following errors are observed in the event log after modifications made to the Export parameter SP_XPT_SO_SNDBUF and/or sp_cop parameter SP_COP_SO_RCVBUF during tuning of Export:

Process launched: sp_xport (to test2 queue test) [pid = 1773854]
01/17/08 11:59 Error: sp_xport: cannot adjust socket SO_SNDBUF - exiting [sp_xport/1773854]
01/17/08 11:59 System call error: No buffer space available setsockopt error [sp_xport/1773854]

They may or may not be accompanied by slow Export.

Incorrect setting of one or both of the parameters SP_XPT_SO_SNDBUF and SP_COP_SO_RCVBUF is causing this.

Ideally both these parameters should have identical setting.  The parameters are described in Shareplex Reference Guide.  The range of valid values for these parameters is: positive integers, in bytes, using multiples of 1024. Maximum is set by the operating system. The Guide does mention that setting of SP_XPT_SO_SNDBUF can be higher than that of SP_COP_SO_RCVBUF but at times this may cause errors. To resolve the issue, carry out the following:

1. Check to see that the parameter is set to a multiple of 1024.
2. Check to see that the parameter is set to a positive integer value.
3. If both para 1 and 2 above are true and if the SP_XPT_SO_SNDBUF has been set to a value higher than SP_COP_SO_RCVBUF, then modify one of them so that they have identical setting.
4. If 1, 2 or 3, fail to resolve the error, then reset the parameters back to the default by sp_ctrl command "reset param <parameter name>".  This is to rule out any setting above OS permissible range. The default of 0 allows OS to handle setting of the parameter. Otherwise you will have to determine the correct OS limit.

On Source the export process must be restarted in order for SP_XPT_SO_SNDBUF to take effect.

sp_ctrl>set param SP_XPT_SO_SNDBUF <value>
sp_ctrl>stop export
sp_ctrl>start export

On target the sp_cop process must be restarted in order for SP_COP_SO_RCVBUF to take effect.

sp_ctrl>set param SP_COP_SO_RCVBUF <value>
sp_ctrl>shutdown
Then restart sp_cop.