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the deterioration of performance is a variety of factors, and sometimes the results of the performance degradation caused by multiple elements, this requires the database administrator has a more comprehensive computer knowledge, can be sensitive to the impact of the database performance of the main reason. In addition, good database management tools are also im
Io is very relevant, when the free buffer waiting in the v$session_wait of the entry is very small or not, Explain the DBWR process of your system will be enough, do not need to adjust, there are many items of free buffer wait, your system must feel very slow, then your DBWR is not enough, the resulting wio has become your database performance bottlenecks, the solution is as follows:
A.1 to increase the write process while adjusting the db_block_lru_
so that you can mark the snapshot information set at important times. A baseline is defined between a pair of snapshots, and the snapshot is identified by their snapshot sequence number. eachThe baseline has only a couple of snapshots. A typical performance tuning practice starts with collecting baseline collections of metrics, making changes, and then capturing another set of baselines. You can compare th
oracle| Data | database | Performance Oracle is a high-performance database software. The user can adjust the parameters to achieve the optimization of performance. Performance optimization is mainly divided into two parts: first,
Document directory
Preliminary steps
Using bind variables
There are several relatively easy steps you can take to improve performance. From the user's perspective, one of the most frequently used interfaces with a database involves SQL statements, so getting a handle on them is a good place to start, in terms of being able to see an immediate improvement. -->Oracle
to select the crosstab (intersection table) as the underlying table, which is the table referenced by the other table.Like what: The EMP table description describes the intersection of the location table and the category table. SELECT * FROM location
L,
CATEGORY C,
EMP E
WHERE e.emp_no between, and
e.cat_no = C.cat _no and
e.locn = L.LOCNwill be more efficient than the following SQL: SELECT * from
EMP E, location
L,
CATEGORY C
WHERE e.cat_no = c.cat_no and
e.locn = L.
monitoring is necessary 207Thinking on the construction of 6.7 operation and maintenance platform--meta data management 2096.8 Monitoring blind spots and diagnostic cases 210Monitoring blind spots: A potential monitoring problem caused by dual 210Diagnostic Case: Standby CPU Usage Exception Optimization 213Diagnostic Case: Two alarm information combined with analysis of DG Problem 216Diagnostic case: Monitoring anti-monitoring error--an analysis of a Orabbix alarm 222Diagnostic case: Customizin
Summary: This article begins with a detailed introduction to the concept of shared pool in Oracle and the memory structure included. It then provides an in-depth overview of Oracle's management mechanisms for shared pool. Finally, the paper introduces the practical method of buffer cache monitoring and tuning.
1. The concept of shared pool
Oracle databases, as
first wait event is read by other session.
Top 5 Timed Foreground Events
Read by other session is defined as follows:
Read by other session Definition: When information is requested from the database, Oracle will first read the data from disk into the database buffer cache. if two or more sessions request the same information, the first session will read the data into the buffer cache while other sessions wait. in previous versions this wait was clas
As mentioned in parts 1th and 2nd, there are several relatively easy steps to improve performance you can take, one of these steps involves using an automated tool to "guide" you to write SQL statements, there are many production performance analysis or performance tuning tool manufacturers, in the following article, W
This technical article, provided by the International Oracle User Group (IOUG), is a user-organized organization that enhances the level of Oracle database experts and database developers by providing high-quality information, training, networking, and support. This article picks up the "Predictable Oracle Application Perform
Summary of Oracle Performance Tuning recommendationsPrinciple One: Note the connection order in the WHERE clause:Oracle uses a bottom-up sequential parsing where clause, according to which the connection between tables must be written before other where conditions, and those that can filter out the maximum number of records must be written at the end of the WHERE
Buy Oracle Database Course package and enjoy 85 discount!!Package Address: http://edu.51cto.com/pack/view/id-807.htmlPerformance optimization for Oracle 11g R2 databaseDatabase performance problem is the most discussed topic in database field, because it involves database principle, IO storage, server performance, fore
Tags: process optimizer consolidation requires merging auto overwrite session accessThe full execution order of the SELECT statement:The full execution order of the SQL SELECT statement: 1. The FROM clause assembles data from different data sources; 2. The WHERE clause filters the record rows based on the specified criteria, 3, the GROUP BY clause divides the data into multiple groupings, 4, uses the aggregation function for the calculation, 5, uses the HAVING clause to filter the grouping; 6, e
"Performance Tuning" Oracle AWR reporting metrics full resolution
What is AWR?
=====================================================================================================
AWR (Automatic workload Repository)
A bunch of historical energy data, placed on the Sysaux table space, AWR and Sysaux are all 10g, are the key features of
GROUP BY:Increase the efficiency of the group BY statement by filtering out unwanted records before group by. The following two queries return the same result but the second one is significantly faster.Copy CodeThe code is as follows:Low efficiency:SELECT JOB, AVG (SAL)From EMP GROUP job has job = ' president ' and AVG (SAL) >xxxEfficient:SELECT JOB, AVG (SAL)From EMPWHERE JOB = ' President 'OR job = ' MANAGER ' GROUP JOB having and AVG (SAL) >xxx7, usually, if the statement can avoid the use o
are very readable6. Use where to replace having (if possible)Optimize GROUP BY:Increase the efficiency of the group BY statement by filtering out unwanted records before group by. The following two queries return the same result but the second one is significantly faster. Copy the code code as follows: Low efficiency:SELECT JOB, AVG (SAL)From EMP GROUP job has job = ' president ' and AVG (SAL) >xxxEfficient:SELECT JOB, AVG (SAL)From EMPWHERE JOB = ' President 'OR job = ' MANAGER ' GROUP JOB hav
Friends who are interested in this course can add my QQ2059055336 and contact me.This course focuses on Oracle RAC architecture and how it works, understanding and mastering the relevant technologies under the RAC database, such as cache Fusion, Failover, load balance, FAN, OCR, and voting disk. Through the implementation of the VMware virtual environment, the installation and deployment of RAC database, the daily
Oracle is a high-performance database software. The user can adjust the parameters to achieve the optimization of performance. Performance optimization is mainly divided into two parts:
First, the database administrator through the adjustment of system parameters to achieve the goal of optimization;
The second is tha
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