oracle dba performance tuning

Oracle Performance tuning is a broader and somewhat more complex topic, and the biggest problem for ordinary DBAs is where to start and what to do. All the information you know may be someone (a user) who reports a problem with the performance degradation of an application or query, and where do you start when faced wi

of disk sorting will be greatly increased. This is mainly because at the end of the month, users will make statistics on the transaction data for the month. So at the beginning of the month, because of the number of transactions, so there will be more disk sorting occurs. In this case, it is necessary for the database administrator to adjust the relevant parameters. However, this adjustment is a temporary adjustment, until the cycle has passed, still need to transfer the parameters back. Only i

Absrtact: By discussing and studying the characteristics and principles of Oracle Server and Client/server, this paper expounds some principles and methods of improving and adjusting the performance of Oracle Application system. Keywords: Oracle; client/server; system whole zone; network I/O; rollback segment.

"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

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

Everything has its source, to solve the problem, also have to start from the source, the impact of Oracle performance is very many sources, including the following: the hardware configuration of the database: CPU, memory, network conditions. 1. CPU: CPU data processing capacity in any machine is often a symbol of the performance of the computer, and

filtering out unwanted records before group by. The following two queries return the same result but the second one is significantly faster.The 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 of subqueries, as far as possible without sub-query.Because the overhead

. Create_snapshot; We can also use the Dbms_workload_repository package to complete the baseline, the default settings and other operations.ADDM (Automatic Database diagnostic Monitor AWR)Oracle is an internal consulting system, can automatically complete the most database of some optimization recommendations, giveSQLThe optimization, the creation of the index, the collection of statistics and other suggestions.ADDM report Generation:Sqlplus>@?/rdbms/

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,

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

-------------------------------------------------------------------------| Id | Operation | Name | Cost (%CPU) |-------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 4 (0) || 1 | TABLE ACCESS by GLOBAL INDEX rowid| SALES | 4 (0) || 2 | INDEX RANGE SCAN | Index_qu_sold | 3 (0) |-------------------------------------------------------------------------9 Rows selectedSql> alter session Set "_use_nosegment_indexes" =true;Session altered.Sql> CREATE index

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

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.

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

For some distributions today, there are already three dynamic performance views available to DBAs (database Administrator, DBA) and developers, respectively, V$sql, V$sqlarea, and V$sqltext. These views can be used to collect statistical information about the execution of SQL commands. The fourth dynamic performance view, V$sqlstats, is added to

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