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6.6.14.6: Notes about various databases

6.6.14.6: Notes about various databases

This article provides miscellaneous tips for using supported databases. See also the related links.

  Always consult the product prerequisites Web site for a list of the database brands and versions that are supported by your particular Application Server version, edition, and fix pack.

  • Do not drop the administrative database while the administrative server is running.
  • DB2 performance on a local machine can be improved by setting up a local database as a remote instance. On UNIX systems, this is required. The configuration uses TCP/IP instead of shared memory.

    Oracle and Sybase also support client/server connections. Consult their product documentation for specifics.

  • If using local DB2 databases for data access by session clients, in some cases, multiple connections for session clients cannot be established successfully. To avoid stale connections when there are large numbers of session clients, catalog the DB2 databases using a TCP/IP loopback.

    1. Set up a TCP/IP port in /etc/services, if a port for remote DB2 clients has not been established yet.
    2. Ensure that the TCP/IP communication protocol has been specified in the DB2COMM registry parameter.

      • To check the current setting of the DB2COMM parameter, enter db2set DB2COMM.
      • To update the DB2COMM registry variable to include TCP/IP, use the db2set command.

      For example:

      db2set DB2COMM=existing_protocol_names, tcpip
      
    3. Update the SVCENAME database manager configuration parameter to the connection service name as defined in /etc/services (step 1). For example:
      db2 update dbm cfg using svcename connection service name
      
    4. Catalog the loopback node. For example:
      db2 catalog tcpip node node_name remote 
      127.0.0.1 server connection_service_name
      
    5. Catalog the database as follows:
      db2 catalog db database_name as database_alias
      db2 uncatalog db database_name
      db2 catalog db database_alias as database_name at node node_name
      

      This allows you to implement a TCP/IP loopback without needing to change the application to connect to the new alias and the USER and USING parameters.

    6. Stop DB2 and start it again to refresh the directory cache.
  • When using Sybase 11.x, you might encounter the following error when HttpSession persistence is enabled:
    DBPortability W Could not create database table: "sessions"
    com.sybase.jdbc2.jdbc.SybSQLException: The 'CREATE TABLE' command is not
    allowed within a multi-statement transaction in the 'database_name' database
    where 'database_name' is the name of the database for holding sessions.

    If you encounter the error, issue the following commands at the Sybase command line:

    use database_name
    go
    sp_dboption db,"ddl in tran ",true
    go
    
  • Sybase 12.0 does not support local transaction modes with a JTA enabled data source. To use a connection from a JTA enabled data source in a local transaction, Sybase patch EBF9422 must be installed.

Go to previous article: Additional administrative tasks for specific databases Go to next article: Recreating database tables from the exported table DDL

 

 
Go to previous article: Additional administrative tasks for specific databases Go to next article: Recreating database tables from the exported table DDL