SQL-Retriever ODBC

FAQ

FAQ: SQL-Retriever gives the error 'Communication link failure.

During the initial connection of SQL-Retriever, the error message "Communication link failure" occurs. The error message can also occur after initial connection, in which case it is likely to be something else, such as caching.

Solution

First, check that you can connect from the PC to the UNIX machine with vt52/telnet. If you can, then the basic connectivity is intact.

Next, consider these items:

  1. Check the permissions on the directory where SQL-Retriever is installed.
  2. Check the permissions on the SQL-Retriever configuration file.
  3. Check for incorrect settings of INFORMIXDIR or SQLEXEC in the case of Informix in the SQL-Retreiver configuration file. (This could also apply to the equivalent for other databases, such as II_SYSTEM).
  4. Check for a corrupt datasource settings (VWODBC.INI in \WINDOWS for 16-bit or the Registry settings for the datasource for 32-bit ODBC).
  5. Check for problems of mismatch with the versions of VWODBC.DLL (16-bit ODBC) or VWODBC32.DLL (32-bit).
  6. Look for possible caching problems. Try turning caching off (FetchCache=0 for 16-bit ODDBC or disable caching in the Datasource/Advanced Setup for SQL-R 4+).
  7. Look for any possible problem with Ingres/Solaris with uneven length of var char less than 8.
  8. If on SCO and starting the SQL-Retriever server from a boot file, in a VERY few cases, the server will appear to start, but will not allow a connection from Gold with "Communication link failure".

This is not a complete list; there may be other causes. Sometimes, the above causes will generate an SQL-Retriever host debug log which will shed some light on the problem.

Note: SQL-Retriever (v4) is installed by default under /usr/local/vision. The configuration file is usually found in the etc directory and is called infsqld.conf (in the case of Informix).