Apache DAD Switching to Failover Instance

Question

Hi,
Is there any way to make the DAD switch to failover instance or connect to diff host,diff port if the database connection with already exist one in DAD failed ?
If there how to perform through DAD means what should be the syntax of failover instance entry for DAD ? I am implicitely telling all about HTMLDB point of view to make Apache HTTP server DAD failover to other instance.
Plz guide me .......
Thanks & Regards,
ROSY

Answer 1

Rosy,
What I'm saying (and Scott earlier) is that this is not a htmldb issue.
Looking at my standard $ORACLE_HOME/Apache/modplsql/conf/marvel.conf file I have this entry
          <Location /pls/htmldb>
          SetHandler pls_handler
          Order deny,allow
          Allow from all
          AllowOverride None
          PlsqlDatabaseUsername HTMLDB_PUBLIC_USER
          PlsqlDatabasePassword @BTg2dUbwDsAJ5f8nREPzuyA=
          PlsqlDatabaseConnectString localhost:1521:dually ServiceNameFormat           PlsqlDefaultPage htmldb
          PlsqlDocumentTablename wwv_flow_file_objects$
          PlsqlDocumentPath docs
          PlsqlDocumentProcedure wwv_flow_file_manager.process_download
          PlsqlAuthenticationMode Basic
          PlsqlNLSLanguage AMERICAN_AMERICA.WE8MSWIN1252
          </Location>
In this case my host is localhost my sid is dually and the port is 1521.
If I make a entry in my $ORACLE_HOME/network/admin/tnsnames.ora that points to my database
HTMLDB =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
(CONNECT_DATA =
(SERVICE_NAME = dually)
I can now change my marvel.conf file to use this entry
          <Location /pls/htmldb>
          SetHandler pls_handler
          Order deny,allow
          Allow from all
          AllowOverride None
          PlsqlDatabaseUsername HTMLDB_PUBLIC_USER
          PlsqlDatabasePassword @BTg2dUbwDsAJ5f8nREPzuyA=
          PlsqlDatabaseConnectString HTMLDB
          PlsqlDefaultPage htmldb
          PlsqlDocumentTablename wwv_flow_file_objects$
          PlsqlDocumentPath docs
          PlsqlDocumentProcedure wwv_flow_file_manager.process_download
          PlsqlAuthenticationMode Basic
          PlsqlNLSLanguage AMERICAN_AMERICA.WE8MSWIN1252
          </Location>
As you are probably aware I can have multiple entries in this file so I could change the location to say "/pls/production"
          <Location /pls/production>
          SetHandler pls_handler
          Order deny,allow
          Allow from all
          AllowOverride None
          PlsqlDatabaseUsername HTMLDB_PUBLIC_USER
          PlsqlDatabasePassword @BTg2dUbwDsAJ5f8nREPzuyA=
          PlsqlDatabaseConnectString HTMLDB
          PlsqlDefaultPage htmldb
          PlsqlDocumentTablename wwv_flow_file_objects$
          PlsqlDocumentPath docs
          PlsqlDocumentProcedure wwv_flow_file_manager.process_download
          PlsqlAuthenticationMode Basic
          PlsqlNLSLanguage AMERICAN_AMERICA.WE8MSWIN1252
          </Location>
Now I can use the tns entry to direct where the database connections go. There are a number of solutions for DR that you can use with tns names. You really need to spell out what your configuration is ie do you run physical standby? dataguard? how do you failover. How many web servers do you have? one on each machine? Lots of different things can be done here and as Scott mentioned they are a bit outside the scope of this forum.
The question you need to be asking is "How do I manage connections from my client (Apache) to my DR site"
Here is some reading
http://asktom.oracle.com/pls/ask/f?p=4950:8:::::F4950_P8_DISPLAYID:52258813563764
good luck
Chris