V$RESOURCE_LIMIT

“V$RESOURCE_LIMIT” Reference Note Oracle9i Information This view displays information about global resource use for some of the system resources. Use this view to monitor the consumption of resources so that you can take corrective action, if necessary.Some resources, those used by DLM for example, have an initial allocation (soft limit), and the hard limit, which . . . → Read More: V$RESOURCE_LIMIT

Init.ora Parameter "OPTIMIZER_FEATURES_ENABLE" Reference Note

Reference Note for Init.Ora Parameter “OPTIMIZER_FEATURES_ENABLE”. This note contains links to documentation for the server parameter OPTIMIZER_FEATURES_ENABLE along with any additional “Support / Historical Notes” and “Known Bugs” (if any) which may affect or be impacted by the value of this parameter. OPTIMIZER_FEATURES_ENABLE Documentation 11.1 Online Reference for OPTIMIZER_FEATURES_ENABLE 10.2 Online Reference for OPTIMIZER_FEATURES_ENABLE 10.1 . . . → Read More: Init.ora Parameter "OPTIMIZER_FEATURES_ENABLE" Reference Note

Recommended Hidden Parameters for 11gR1

Question #1: ========== _optimizer_cost_based_transformation=false Currently set to false, should we keep or remove it for 11g upgrade? It is a workarond for several bugs, including ORA-600 bug 6666870 fixed only in 11,2?

ANSWER ======= _OPTIMIZER_COST_BASED_TRANSFORMATION controls whether or not the optimizer tries different transformations against a query using the cost with and without the transformations . . . → Read More: Recommended Hidden Parameters for 11gR1

Diff Hidden Parameter between 10g and 11g

 

Know more about _in_memory_undo

set parameter _in_memory_undo = FALSE to disable IMU

Workaround: Disable IMU (set _in_memory_undo=FALSE)

PLEASE NOTE: This bug applies to single instance databases and not RAC as IMU is not enabled in RAC.

注意在RAC系统中IMU是不可用的,所以也就不必要去设置_in_memory_undo=FALSE

The workaround will prevent the problem, but will not fix it.

Note: _in_memory_undo is a dynamic parameter for 10g with values . . . → Read More: Know more about _in_memory_undo

Know Oracle Process OS Scheduled Priority

Can you kindly define and explain of this parameter?

_os_sched_high_priority

 

Regarding _os_sched_high_priority :

Setting LMS priority automatically via _os_sched_high_priority It has been proven that performance is increased when LMS processes are running in the real time priority class, as opposed to the timesharing class. The parameter _os_sched_high_priority was introduced in Oracle 10g Release . . . → Read More: Know Oracle Process OS Scheduled Priority

EFFECT OF GLOBAL_NAME, GLOBAL_NAMES ON DB LINKS

Applies to:

Oracle Server – Enterprise Edition – Version: 7.3.2.0 to 11.1.0.7 – Release: 7.3.2 to 11.1 Information in this document applies to any platform.

Symptoms

The Effect of GLOBAL_NAME and GLOBAL_NAMES on Database Links:

Changes

{CHANGE} Cause

N/a Solution ============================================================= GLOBAL_NAME ———– GLOBAL_NAME is of datatype VARCHAR2(2000). GLOBAL_NAME is the name of the database. . . . → Read More: EFFECT OF GLOBAL_NAME, GLOBAL_NAMES ON DB LINKS

Init.ora Parameter "_COMPLEX_VIEW_MERGING" Reference Note

Reference Note for Init.Ora Parameter “_COMPLEX_VIEW_MERGING”. This parameter is a hidden (underscore) parameter Such parameters should only ever be set under the guidance of Oracle Support. Clearly document why the parameter is set including reference to any SR, Bug or Note Summary Version Information Version Parameter Type Modifiable 11.1.0.6 _complex_view_merging BOOLEAN ALTER SESSION ALTER SYSTEM . . . → Read More: Init.ora Parameter "_COMPLEX_VIEW_MERGING" Reference Note