Database Parameter Configuration

 

Data Access Driver

The Data Access Driver section of the screen allows administrators to display the settings for all the data access drivers. The drivers do not have to be configured to display the settings. Drivers that are installed and not configured have an "X" on the left side of the screen.

Driver

Database access is achieved through a data access driver, which is software written either by the database vendor or a third-party vendor.

The following types of data access drivers can be configured with NAS to provide database connectivity:
  • Oracle
  • DB2
  • Informix
  • Sybase
  • MSSQL Server (NT)

Priority

An application developer can specify that an application interact with a database driver called default. When default is specified, NAS sends the request to the driver with the highest priority.

General Settings

Enable SQL Parsing

When enabled, SQL statements are parsed by NAS and then sent to the database. If NAS cannot parse the SQL an error is returned. This feature is useful for developers using generic SQL that interacts with multiple databases. Use this feature during the testing and staging phases of application development.

Log Debug Messages

 
This option logs database interaction in detail. To view the messages being logged, look at the appropriate kjs or kcs engine log. This feature is useful during testing, staging, and production. You can turn the option off after an application is successfully launched into production but you can turn it back on at any time to monitor database interaction.

Connection Timeout

Allows the administrator to set the amount of time in seconds to wait before giving up on a request to establish a database connection. If the indicated time is reached and a connection has not been made, the request is taken out of the queue.

Thread Parameters

The database thread parameters determine how many threads NAS allocates for asynchronous database queries. Each thread uses a small stack allocation and pulls from the total number of available system threads. If the developer uses asynchronous queries, increasing the number of threads can increase performance. Asynchronous threads are not supported by the JDBC 4.0 interface. Therefore, if the applications housed on a server do not use any asynchronous queries, you can increase performance by setting the maximum available threads to zero.

Cache Parameters

The database cache is an array used to hold active and recently used database connections. While an application is using a database connection, NAS marks the connection as in use. After the database operations finish, the server marks the database connection free. The cache then holds the free connection in the cache for a configured period of time. This allows the server to reuse the free cached connection and quickly handle a new request to the same database. After a free connection exceeds the timeout, a cleaning thread removes the connection from the cache and opens a slot for a new connection to be cached.

Maximum Connections

This is the maximum number of connections a NAS server can have to the database. The setting for this depends on the application and on the number of connections the database allows.

Free Slots

Free Slots is the number of cached connections. This is the number of connections to be held in cache. When this number is exceeded then connections must time-out as soon as the database interaction becomes idle.

Timeout

Timeout is the number of seconds a connection remains in cache before being cleaned out. This number could be set to a large number equaling days, depending on the needs of the application.

Interval

Interval is the amount of time before the cache thread cleaner checks connections. Connections with a timestamp showing a greater amount of time than indicated for timeout are disconnected from the database and cleared from memory.