A named database declaration tells rwloadsim a database and a schema to connect to (username, password and connect string) and tells how the connection is done (e.g. dedicated or using a session pool). You can declare as many databases as needed, and you can mark one database as being the “default” database, which is used when no explicit database is named. You can similarly mark one database as the “results” database, which is used by rwloadsim to store run time results.
The following lists some examples with explanation.
Declare a database called testdefault, that will have a connection established in the main threads and all threads, and which will be used by default when no at database is used:
database testdefault
username "username"
password "{password}"
connect "//host/service:dedicated"
dedicated
default;
Declare a database called testpool using a session pool with between 1 and 5 sessions. A session will be acquired as needed. This type of pool is often referred to as a “stateless connection pool” because no database state can be kept when the connection is released back to the pool. In Java/JDBC terms, this much like UCP or Universal Connection Pool. To use it, you must explicitly name it using at testpool:
database testpool
username "username/{password}@//host/service:dedicated"
sessionpool 1..5;
This example also shows how you can provide all three parts as the username by separating them by respectively / and @ similarly to how sqlplus does it.
Declare a database called testthronly, that will have a connection established in the main threads only if actually needed, but persistently in all threads:
database testthronly
username "username"
password "{password}"
connect "//host/service:dedicated"
threads dedicated;
Declare a database called testdrcp, that will have a connection established as a drcp connection whenever a procedure needs a database session:
database testdrcp
username "username"
password "{password}"
connect "//host/service:pooled"
drcp;
Declare a database called testpooldrcp, it will be a session pool with variable size between 0 and 5 in your rwloadsim program, and it will further be connected to a pooled data source such as PRCP or DRCP:
database testpooldrcp
username "username"
password "{password}"
connect "//host/service:pooled"
sessionpool 0..5;
Note that even when you declare multiple database, there is no support for two-phase-commit. You should not expect two-phase-commit in a later release.
For security reasons, you do not need to include actual database passwords in your file with database declaration. If you omit the password clause, rwloadsim will prompt you for it. If you do include it, you must always ensure the files containing passwords are not accessible to anybody else.
In addition to session pooling (often referred to as “stateless connection pool”), rwloadsim also supports connection pools that are implemented using OCIConnectionPool. A connection pool is in some ways similar to running shared server in the database, as the application side establishes a number of connections to server processes in the database. These server processes will automatically be shared by multiple sessions. Consider this example:
database cpool
username "username" password "{password}"
connect "//host/service"
connectionpool 1..4;
database realdb
username "username" password "{password}"
connect connectionpool cpool
dedicated default;
procedure dbwork() ... end ;
run
threads 10
dbwork();
end threads;
end run;
The first database, cpool, is a connection pool with initially one connection and one server process that can grow to a maximum of four; this database cannot be used directly as it has no session associated with it. The next database, realdb, uses the pool in stead of connecting directly to the database server. Therefore the ten sessions that are created in the ten threads, will share those four processes when doing the actual database work. Note that as with shared server, the memory used by the sessions for cursors etc will be allocated in the database shared memory rather than in process memory.
Certain settings of databases can be modified using a modify database statement.
As an example, you can change the number of entries in a session pool database using a command like:
modify database testpool sessionpool 1..2;
which would set the range for sessions in the pool to between 1 and 2.
See rwlman databasestatement for details.