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• System configuration requirements for large environments
• In our laboratory tested environments

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System configuration requirements for large environments

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Precise configuration

Precise registry parameters should be set in the <Precise_root>\products\i3fp\registry\products\infrastructure\sts\settings.xml file:
Table A-1 Registry parameters in the settings.xml file

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Oracle 11g

In Oracle 11g the automated maintenance tasks infrastructure known as AutoTask enables Oracle to automatically schedule Automatic Maintenance Tasks. AutoTask schedules automatic maintenance tasks to run in a set of Oracle Scheduler windows known as maintenance windows. Maintenance windows are those windows that are members of the Oracle Scheduler window group MAINTENANCE_WINDOW_GROUP.
Oracle 11g includes three automated database maintenance tasks:

• Automatic Optimizer Statistics Collection - Gathers stale or missing statistics for all schema objects. The task name is auto optimizer stats collection.
• Automatic Segment Advisor - Identifies segments that could be reorganized to save space. The task name is auto space advisor.

• Automatic SQL Tuning Advisor - Identifies and attempts to tune high load SQL. The task name is sql tuning advisor.

  NOTE	If you experience performance problems in Precise during the default maintenance times, we recommend to change the maintenance schedules or ask advice from your Oracle DBA. It is recommended to use a block size of 16 Kbytes.

  The following tables describe the Oracle-based PMDB configuration parameters and sizing recommendations that need to be inserted in the init.ora file for Oracle 11g:
  Table A-6 Oracle 11g-based PMDB configuration parameters

  Parameter	Value
  MEMORY_TARGET	45 GB
  MEMORY_MAX_TARGET	45 GB
  LOG_BUFFER	5 MB
  SESSIONS	1500
  PROCESSES	1000
  UNDO_RETENTION	7200
  DB_WRITER_PROCESSES	4

  Table A-7 Oracle 11g-based PMDB sizing recommendation

  Description	Value
  Redo Log	500 MB for 90 instances, 1000 MB for 180 instances, 2000 MB for 450 instances
  PMDB Temporary Tablespace	4 files and each file 32 GB
  Undo Tablespace	4 files and each file 32 GB

  If on a Linux server you get an ORA-845 error, /dev/shm needs to be mounted with its proper size. The size is directly influenced by the SGA size of your PMDB. If you set it too low you will get this error.
  To mount it, log in as a root user and use the following command: # mount -t tmpfs shmfs -o size=<SGA size> /dev/shm
  To activate the setting and make it permanent after a restart, add the entry in /etc/fstab.

  Oracle 10g

  By default Oracle 10g automatically gathers optimizer statistics using a scheduled job called GATHER_STATS_JOB. By default this job runs within a maintenance windows between 10 P.M. to 6 A.M. week nights and all day on weekends. The job calls the DBMS_STATS.GATHER_DATABASE_STATS_JOB_PROC internal procedure which gathers statistics for tables with either empty or stale statistics, similar to the DBMS_STATS.GATHER_DATABASE_STATS procedure using the GATHER AUTO option. The main difference is that the internal job prioritizes the work such that tables most urgently requiring statistics updates are processed first.

  NOTE	If you experience performance problems in Precise during the default maintenance times, we recommend to change the maintenance schedules, or ask advice from your Oracle DBA.

  It is important to understand that there are two scheduled activities related to the collection of Oracle "statistics". These are very different:

• AWR statistics: Oracle has an automatic method to collect AWR "snapshots" of data that is used to create elapsed-time performance reports.

• Optimizer statistics: Oracle has an automatic job to collect statistics to help the optimizer make intelligent decisions about the best access method to fetch the desired rows.

  NOTE	It is recommended to use a block size of 16 Bytes.

  The following tables describe the Oracle-based PMDB configuration parameters and sizing recommendations that need to be inserted in the init.ora file for Oracle 10g:
  Table A-8 Oracle 10g-based PMDB configuration parameters

  Parameter	Value
  SGA_TARGET	45 GB
  SGA_MAX_TARGET	45 GB
  LOG_BUFFER	5 MB
  SESSIONS	1500
  PROCESSES	1000
  UNDO_RETENTION	7200

  Table A-8 Oracle 10g-based PMDB configuration parameters

  Parameter	Value
  DB_WRITER_PROCESSES	4

  Table A-9 Oracle 10g-based PMDB sizing recommendation

  Description	Value
  Redo Log	500 MB for 90 instances, 1000 MB for 180 instances, 2000 MB for 450 instances
  PMDB Temporary Tablespace	4 files and each file 32 GB
  Undo tablespace	4 files and each file 32 GB

  If on a Linux server you get an ORA-845 error, /dev/shm needs to be mounted with its proper size. The size is directly influenced by the SGA size of your PMDB. If you set it too low you will get this error.
  To mount it, log in as a root user and use the following command: # mount -t tmpfs shmfs -o size=<SGA size> /dev/shm
  To activate the setting and make it permanent after a restart, add the entry in /etc/fstab.
  

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  SQL Server-based PMDB configuration

  NOTE	You should place the data and log files on different disks.

  The following table describes the SQL Server-based instance configuration parameters:
  Table A-10 SQL Server-based instance configuration parameters

  Parameter	Value
  SQL Server memory	44000 MB
  Minimum memory per query	307200 KB

  
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  The following table describes the SQL Server-based PMDB (database) configuration parameters for the files:
  Table A-11 SQL Server-based PMDB (database) configuration parameters for the files

  Parameter	Value
  Data	5000 MB
  Log	1000 MB

  NOTE	The autogrowth parameter should be 100 MB.

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  The following table describes the SQL Server-based PMDB (database) configuration parameters for the options:
  Table A-12 SQL Server-based PMDB (database) configuration parameters for the options

  Parameter	Value
  Auto Update Statistics	True
  Auto Update Statistics Asynchronously	True
  Auto Create Statistics	On
  Recovery Model	Simple

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  The following table describes the SQL Server-based tempdb configuration parameters:
  Table A-13 SQL Server-based tempdb configuration parameters

  Parameter	Value
  tempdb Auto Update Statistics	False
  tempdb Auto Update Statistics Asynchronously	False
  tempdb Auto Create Statistics	False

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  In our laboratory-tested environments

  The following table shows the environments that we tested in our laboratory:
  Table A-14 Tested environments

  Criteria	Oracle-based PMDB	SQL Server-based PMDB
  J2EE instances	300	180
  Web instances	150	90
  Total number of instances	450	270
  Server platform	Linux 64 bits	Windows 2008 64 bits
  Processors	Dual quad core CPU X5570 (8 cores)	Dual 6 core CPU X5670 (12 cores)
  Physical memory	68 GB (Oracle SGA - 45 GB)	60 GB (SQL Server memory - 44 GB)
  Storage for data files	EMC Symmetrix VMAX	Local 15 K SAS disks
  Data files size	1.5 TB	1 TB