Connection Options

IDS on both Windows NT and UNIX systems have a relatively recent option (beginning with 7.10) to the sqlhosts file (or registry) that provides security and maintenance information to Informix-Connect. These options are placed in the sqlhosts file as the last field, as follows:

   ol_theserver   onsoctcp   the_server  turbo   k=1,s=1,b=4000

Everything to the right of the "turbo" is options, separated by commas. These options have the following meanings. On later NT systems (IDS 7.3+), the setnet32 program has a separate listbox for options. On earlier NT systems it may be possible to set or change these options by manually editing the registry. Back it up first.

Keep-Alive Options (k)

These options determine what happens when the networking system detects that the client and server are not communicating. Keep-alive can be enabled on the client end, the server end, or both. These keep-alive options are used for networking protocols over TCP/IP or IPX/SFX. If keep-alive is enabled from the client side, the networking service will periodically poll the engine to see if it is still alive. If keep-alive is enabled from the engine side, the networking service will periodically poll the clients to see if they are still alive. If the polling side does not contact the polled side within a certain time limit (usually determined by an operating system kernel parameter), the polling system's resources are released when the connection fails.

The problem here is that the networking system expects a return communication within a certain amount of time. If the connection is still active, but response time is slowed significantly because of network traffic, the system can be fooled into thinking that the connection is broken, when in fact it is only slow.

The default value is k=1, which enables keep-alive. Having keep-alive active does impose an additional load on both the system and the network, but unless your network is horribly saturated to the state that the additional networking load is significant and you are getting frequent false disconnects because of network latency, keep it enabled.

   k=0, Disables the keep-alive feature.
   k=1, Enables the keep-alive feature.

Security Options (r, s)

These options control whether or not the networking service allows usage of the various UNIX security files listed on previous pages.

   r=0, Disables the ~/.netrc lookup from the client side.
   r=l, Enables the ~/.netrc lookup from the client side default setting for the client side).
   s=0, Disables both /etc/hosts.equiv and ~/.rhosts lookup from the server side.
   s=1, Enables only the /etc/hosts.equiv lookup from the server side.
   s=2, Enables only the ~/.rhosts lookup from the server side.
   s=3, Enables both /etc/hosts.equiv and ~/.rhosts lookup on the server side (Default setting
   for the server side).

Buffer Options (b)

Unless specified with this option, the operating system will determine how large the buffers should be for the communications between systems. If you find yourself consistently transferring very large buffers, you may gain some speed improvements by adjusting the buffer sizes. The buffer sizes should be identical on both client and server. This parameter can be useful in handling the transfer of large blobs.

   b=n, Specify the space (in bytes) reserved for the communications buffer.

When these Options Become Effective

Options from the client side become effective as soon as you change the parameters either in the setnet32 program or in the sqlhosts file. The next connection made will reflect these new options. For server-side parameters, the options can be changed at any time but will not become effective until the server is shut down and restarted.