User Guide

SAP AG November 2002
• ONLINE: The database instance has been started, and users can log on.
• ADMIN: The database instance is only available to administrators for administrative work.
• OFFLINE: The database instance is not running.
Page
A page is a basic physical unit of disk input and output, that is, a page corresponds to a
certain number of blocks. Storage and disk space is often measured in pages.
For the SAP DB database system, the page size is fixed at 8 KB.
Page Pool
The page pool is used to manage the pages of the I/O buffer cache [Page 138]. The pages of
the I/O buffer cache are dynamically assigned to the Converter [Page 129] and the data
cache [Page 130] using the information in the page pool.
Parallel Backup
Parallel processing is possible for a data backup [Page 131]. In this case, a group of parallel
backup media [Page 138] must be defined.
See also:
Backup Strategy [Page
39]
Saving Data Backups [Page 41]
RESOURCE
RESOURCE users are special database users [Page 136] of the database user class [Page
28] RESOURCE. RESOURCE users can be created by SYSDBA users [Page 151] and DBA
users [Page 137].
RESOURCE users can define data and database procedures and grant other users privileges
for these database objects.
Restart
When the database system is restarted, all the available redo log entries [Page 44] from the
log area [Page 142] are reproduced, and if necessary, undo log entries [Page 44] are
evaluated in order to roll back transactions [Page
152].
The system starts with the status of he database system that was recorded with the last
savepoint [Page 149].
1. Using the transaction file [Page 152], the log reader [Page 50] regenerates the
transaction list [Page 152].
User Manual: SAP DB 146