DBSERVERALIASES configuration parameter

Use the DBSERVERALIASES configuration parameter to specify an alias name, or a list of unique alias names for the database server. Each alias defined by the DBSERVERALIASES configuration parameter can be used in a different connection, as specified by entries in the sqlhosts information.

onconfig.std value
Not set. No aliases are defined.
values
One to 32 alias names, separated by commas. Each alias name can be optionally followed by a minus sign and an integer from 1 - 50 that specifies the number of multiple listener threads to use for the onimcsoc or onsoctcp protocols. For example, the following two alias names each have four listener threads: alias_a-4,alias_b-4. The listener thread number is ignored for other protocols.
The maximum length of an alias is 128 bytes. Additional aliases beyond 32 are ignored. The maximum length of a DBSERVERALIASES entry is 512 bytes. You can include multiple lines of DBSERVERALIASES configuration parameters in the onconfig file.
An alias name must begin with a letter and can include any printable character, except the following:
  • Uppercase characters
  • A field delimiter (blank space or tab)
  • A newline character
  • A comment character (#)
  • A hyphen or minus ( = ASCII 45) character
  • The @ character
  • A blank space
separators
Separate entries with a comma. Do not include blank spaces.
takes effect
After you edit your onconfig file and restart the database server and update the sqlhosts information of each database server.

Usage

If Informix® supports more than one communication protocol (for example, both an IPC mechanism and the TCP network protocol), you must describe each valid connection to the database server with an entry in the sqlhosts information. For example, suppose you have a server that has the name sanfrancisco defined by the DBSERVERNAME configuration parameter setting, and you set a DBSERVERALIASES value of menlo for different connection. You must specify information for both of the sanfrancisco and menlo servers in the sqlhosts information. Similarly, if the database server needs to support both the standard Informix® protocols and the Distributed Relational Database Architecture™ (DRDA®) protocols, assign an alias to the DRDA® database server and add an entry for this alias in the sqlhosts file.

For each alias listed in the DBSERVERALIASES configuration parameter, the database server starts an additional listener thread. If you have many client applications connecting to the database server, you can distribute the connection requests between several listener threads and speed connection times. To take advantage of the alternate connections, program some of your client applications to connect to a database server alias name instead of the database server name.

High-availability cluster servers that use shared-memory connections must also have TCP connection aliases for server-to-server communication. If a high-availability cluster server's DBSERVERNAME is associated with a shared-memory sqlhosts file entry, you must create a TCP alias for the server by setting a DBSERVERALIASES value, setting the HA_ALIAS configuration parameter to the DBSERVERALIASES value, and then creating a TCP sqlhost file entry for the alias.

Note: Service name used for loopback replication group should be added to DBSERVERALIAS list, and it should appear after service name used for primary Enterprise Replication group.