Sybase 12.4.2 Manuale Utente

How Adaptive Server IQ makes connections

 

The network library looks for a database server on a network by broadcasting 
over the network using the 

CommLinks

 connection parameter.

Tuning the broadcast

The 

CommLinks

 parameter takes as argument a string that lists the protocols to 

use and, optionally for each protocol, a variety of network communication 
parameters that tune the broadcast.

For a complete listing of network communications parameters, see Chapter 3, 
“Connection and Communication Parameters” in the Adaptive Server IQ 
Reference Manual.

Caching server 
information

Broadcasting over large networks to search for a server of a specific name can 
be time-consuming. To speed up network connections (except for the first 
connection to a server), when a server is located, the protocol it was found on 
and its address are saved to a file.

The server information is saved in a file named asasrv.ini, in your Adaptive 
Server IQ executable directory. The file contains a set of sections, each of the 
following form:

[Server name]

Link=protocol_name

Address=address_string

How the cache is 
used

When a connection specifies a server name, and a server with that name is not 
found, the network library looks first in the server name cache to see if the 
server is known. If there is an entry for the server name, an attempt is made to 
connect using the link and address in the cache. If the server is located using 
this method, the connection is much faster, as no broadcast is involved.

If the server is not located using cached information, the connection string 
information and 

CommLinks

 parameter are used to search for the server using 

a broadcast. If the broadcast is successful, the server name entry in the named 
cache is overwritten.

If a server name is held in the cache, the cache entry is used before the 

CommLinks

 string.