User Guide

SAP AG November 2002
User Manual: SAP DB ............................................................................................................. 13
Architecture of the Database System .................................................................................. 13
Database Instance ........................................................................................................... 14
Thread........................................................................................................................... 14
User Kernel Thread (UKT) ........................................................................................ 14
Data Writer ............................................................................................................ 15
Log Writer .............................................................................................................. 15
Server Tasks ......................................................................................................... 16
Timer Task............................................................................................................. 16
Trace Writer Task .................................................................................................. 16
User Task .............................................................................................................. 16
Utility Task ............................................................................................................. 16
Special Thread .......................................................................................................... 17
Coordinator............................................................................................................ 17
Dev Thread............................................................................................................ 17
Requester .............................................................................................................. 18
Temporary Dev Thread ......................................................................................... 18
Timer...................................................................................................................... 18
Operating-System-Dependent Special Threads ....................................................... 18
Clock Thread ......................................................................................................... 18
Console Thread ..................................................................................................... 18
Cache............................................................................................................................ 19
Catalog Cache .......................................................................................................... 19
I/O Buffer Cache ....................................................................................................... 19
Converter............................................................................................................... 19
Data Cache............................................................................................................ 20
Log Queue ................................................................................................................ 20
Volume.......................................................................................................................... 21
Data Volume ............................................................................................................. 21
Log Volume ............................................................................................................... 22
Database Instance Type .................................................................................................. 23
SAP DB OLTP .............................................................................................................. 23
liveCache ...................................................................................................................... 23
SAP DB Document Server............................................................................................ 23
SAP DB OLAP .............................................................................................................. 24
SAP DB E-Catalog........................................................................................................ 24
SAP DB Versions and Database Instance Types ............................................................ 24
Operating System Platforms ............................................................................................ 25
Multiprocessor Configuration............................................................................................ 25
User Manual: SAP DB 4