Mimer SQL on Windows
Mimer SQL on Windows > Mimer SQL Wizards > The System Databank Generation Wizard
The System Databank Generation Wizard

The System Databank Wizard creates the System databanks used by Mimer SQL. There are four system databanks:

SYSDB

The System databank is used to store information about all objects in the database system, such as idents, databanks, tables, and so on. This databank is always located in the database home directory.

TRANSDB

The Transaction databank stores all information about ongoing transactions. The databank is used to restart the database after uncontrolled shutdown (or machine failure). If possible this databank should be on a separate disk drive.

LOGDB

The Log databank stores information about all databanks with LOG option. The information is used to recover a databank after a disk crash. LOG option is therefore only used when a system has three or more disk drives, as LOGDB must be on a separate drive to survive a disk crash.

SQLDB

The SQL databank is only used for temporary objects by the system. It contains worktables used for SQL and read-sets used for transaction handling. If complex SQL queries are used which require temporary tables, this databank can grow quite large in order to hold the intermediate results.

The utility scans your system for available hard disk drives. The databanks are spread across the disks according to the following rules:

One disk: All databanks are placed in the database home directory.

Two disks: LOGDB is placed on a separate disk. All other databanks are placed in the database home directory. This is advantageous primarily from a recovery point of view.

Three disks or more: TRANSDB is placed on one disk, LOGDB on the second, and SYSDB and SQLDB in the database home directory. This is advantageous from both a performance and a recovery point of view.

Placing databanks on network drives is not recommended, as this will decrease the performance of your system. Please refer to the Mimer SQL System Management handbook for more detailed information about the system databanks.

Sizes of files in Mimer SQL are specified in number of 4K blocks (4096 bytes). To assist you, each drive referenced has the number of available 4K blocks shown.

The browse button allows you to select the databank filename through an ordinary "Open file"-dialog box.

The SDBGEN utility creates an administrative user called SYSADM. You must set the password for SYSADM. Please note that all passwords in Mimer SQL are case sensitive. Make sure you remember the password for the SYSADM user because there is no way to change the password unless logged in as SYSADM.

In addition to the drive letter the disk number is also shown. If a disk has been partitioned into several partitions the same disk number is shown several times. The above discussion only applies to disks and not to partitions. It does not help recovery if LOGDB is placed in one partition, and the other databanks in another partition on the same disk, as a disk crash almost always affect both partitions on the disk. Therefore, use a unique disk number for LOGDB if possible. The actual layout of disks and partitions can be viewed with the Windows disk administrator.

See Also
SDBGEN - Command Line options