User Guide

SAP AG November 2002
Server Tasks
A server task is a user kernel thread (UKT) [Page 14]. The main purpose of server tasks is to
parallelize database functions such as saving to a group of parallel media, restoring from a
number of media in parallel, and compiling indexes.
When the database parameters are being configured, the number of server tasks is
determined automatically from the number of data volumes [Page
130] [Page 130] and the
number of data backup devices in use.
The maximum number of server tasks available is defined by the MAXSERVERTASKS [Page
86] [Page 86] database parameter.
Timer Task
A timer task is a user kernel thread (UKT) [Page 14]. The timer task handles timeout
situations of all types.
Trace Writer Task
The database system enables the database trace [Page 136] to be activated for the purpose
of diagnosis. The trace writer task (a special user kernel thread (UKT) [Page 14]) is provided
for this.
User Task
When he or it logs on to the database instance [Page 132], each user [Page 14] of the
instance or each application is assigned precisely one fixed user task. The user task ensures
the processing of SQL statements for the database session.
The number of user tasks available is defined by the MAXUSERTASKS [Page
86] database
parameter.
Utility Task
A utility task is a user kernel thread (UKT) [Page 14]. The utility task is reserved solely for
managing the database instance [Page
132].
As there is only one utility task for each database instance, no parallel managing actions can
be performed.
An exception to this rule is the automatic log backup [Page
126]. This can be performed in
parallel with other management actions.
User Manual: SAP DB 16