Errores y bugs relacionados con el DBWn (Database Writer Process)

The primary responsibility of DBWn is to write data blocks to disk. DBWn also handles checkpoints, file open synchronization, and logging of Block Written records.

In many cases the blocks that DBWn writes are scattered throughout the disk. Thus, the writes tend to be slower than the sequential writes performed by LGWR. DBWn performs multiblock writes when possible to improve efficiency. The number of blocks written in a multiblock write varies by operating system.

The DB_WRITER_PROCESSES initialization parameter specifies the number of DBWn processes (DBW0-DBW9 and DBWa-DBWz). The database selects an appropriate default setting for this parameter or adjusts a user-specified setting based on the number of CPUs and processor groups.

Issues Specific to DBWn

Note 243248.1 - Database Startup fails with ORA-443 Background Process "DBW0" did not Start

Note 1065267.6 - ORA-445 Background Process DBW0 Did Not Start After 120 Seconds

Note 1461704.1 - ORA-00600 [kcbbxsv_2] Errors And DBW0: Terminating Instance Due To Error 471 (

Note 6005113.8 - Bug 6005113 - OERI[kclrwrite_7] in DBWn process followed by instance crash in RAC

Database Manageability and Real Application Testing

Database Manageability and Real Application Testing

Demos and How To:
	Script: Oracle Database 11g Database Replay Workload Analyzer ZIP
	Screenwatch: Offline Analysis of Long Running SQL using SQL Monitoring Active ReportsScreenwatch
	Screenwatch: Detecting Unwanted Schema Changes in Real Time using Oracle Change Management Pack Screenwatch
	Screenwatch: Simplify Oracle Database Upgrades Using SQL Performance AnalyzerScreenwatch
	Script: RAC AWR report for Oracle Database 10 g Release 2 ZIP
	Script: RAC AWR report for Oracle Database 11 g Release 1 ZIP
	Examples and Scripts: Command Line Interface Usage of Database Replay ZIP
	Examples and Scripts: Oracle Database 9 i/10.1 to 10.2 Upgrade Use Case with SQL Performance Analyzer ZIP
	Oracle Database 11 g: Automatic SQL Tuning Viewlet
	Oracle Database 11 g: SQL Performance Analyzer Viewlet
	Oracle Database 11 g: Database Replay Viewlet
	Oracle Enterprise Manager 10 g: ADDM Overview  Viewlet
	Oracle Enterprise Manager 10 g: Analyzing ASH Reports Viewlet
	Oracle Enterprise Manager 10 g: Performance Page Overview Viewlet
	Oracle Database 10 g: Installation and Configuration on a Windows Platform Viewlet
	Oracle Database 10 g: Installation and Configuration on a UNIX Platform (Linux) Viewlet
	Oracle Database 10 g: Client Installation on a Windows Platform Viewlet
	Oracle Database 10 g: Upgrade Viewlet
	Oracle Database 10 g: Performance Diagnostics and SQL Tuning Viewlet
	Oracle Database 10 g: SQL Access Advisor Viewlet
	Oracle Database 10 g: Automatic Shared Memory Tuning Viewlet
	Oracle Database 10 g: Proactive Space Management and Segment Advisor Viewlet
	Ref:  http://www.oracle.com/technetwork/database/manageability/demos-and-howtos-083960.html

Ya disponible la documentación ONLINE para Oracle Database 12cR2

Oracle  estableció la estrategia de disponibilizar primero la versión 12cR2 en sus servicios Cloud, deberemos esperar para poder empezar a utilizarla en nuestras instalaciones "On-Premises".
Mientras tanto, podemos empezar a "jugar" con el servicio trial en el cloud y probar nuevas funcionalidades. Ya tenemos disponible la documentación "on line" de la nueva versión para ir quemando nuestros ojos e ir viendo que hay de nuevo:

http://docs.oracle.com/en/database/