Database Manager lets you display a summary of the current database. This summary lists the database's:
- Size in bytes.
- Serial number.
- Contents.
- I/O count.
Using this information can help you manage your databases. For example, knowing the database's serial number can help you determine if someone modified your database since its last save. The serial number is a unique code that Database Manager creates whenever you add or delete a block. By writing down the serial number after you modify the database, you can subsequently compare the current number to the previous one.
High-level documentation about the database can also help you manage your databases. You can provide this level of information by displaying the database's contents. The contents lists by block type the number of blocks used and allocated. A used block is one you have configured. An allocated block is a placeholder in memory. To make efficient use of memory and improve performance, all SCADA servers pre-allocate 10 blocks at a time when you initially create a block of a specific type, as the following figure shows.
Allocating Memory for Database Blocks
As an option, you can restrict your process database to a specific number of I/O blocks (intended for small applications that do not require many I/O points). In this environment, the I/O count lets you determine how many I/O blocks are in use.
