oracle sql tuning tips

Read Catalogue (1) Select the most efficient table name order (valid only in the rule-based optimizer) (2) connection order in the WHERE clause (3) Avoid using ' * ' in the SELECT clause (4) Reduce the number of accesses to the database (5) Reset the ArraySize parameter in Sql*plus, sql*forms and pro*c to increase the amount of data retrieved per database access, with a recommended value of 200

Label: Read Catalogue (1) Select the most efficient table name order (valid only in the rule-based optimizer) (2) connection order in the WHERE clause (3) Avoid using ' * ' in the SELECT clause (4) Reduce the number of accesses to the database (5) Reset the ArraySize parameter in Sql*plus, sql*forms and pro*c to increase the amount of data retrieved per database access, with a recommended

, high concurrency is a high level of CPU consumption caused by recompilation.C, physical connection tips (Hint)About physical connections We have analyzed in detail in the previous article that there are three physical connection methods in SQL Server: Nested loops, merges, Hash joins.You can refer to the links in my basic article: SQL Server

An outline that is roughly written in the optimization content of the physical design and logical design of the DB, mainly physical design, logical design introduction of the content is not much, the outline of the physical structure design and example optimization of organic combination of the logical structure design and application adjustment together ... Oracle Performance Tuning Guidance outline Desi

Do you want to learn some tips for tuning SQL PL? If this is the case, this article will describe some common examples of tuning ibm®db2®universal database™ (UDB) V8.2 for linux,unix®, and Windows®, and will pay special attention to porting from other database management systems Come over the process. Motivation

Tags: end number implementation loop HTML from SQL statement tips preparing CPUObjective In the previous article we described how to view the parallel running of a query plan. In this article we then analyze the parallel operations of SQL Server. Gossip less, directly into the topic of this article. Technical preparation As in the previous few, the

SQL Auto-tuning is an Oracle-brought tuning tool that provides solutions.This time I mainly introduce the following automatic SQL tuning tools: Automatic SQL

Oracle 11g has made some improvements in optimization. Oracle automates the following optimization: Redo Logfile Sizing Advisor-this feature recommends Redo the optimal size of log files to avoid excessive disk I/O caused by frequent checkpoints. Automatic Checkpoint Tuning-Oracle database can now optimize checkp

at the statement level, the hint syntax is:/*+ bind_aware*/;Ø about outlines: In the scene of outlines existence, the ACS will fail whether the system level is enabled or the statement level is enabled through hint;6. Conclusion:New features of Oracle Database 11g The ACS feature provides an easy way to efficiently share SQL statement execution plans with bound variables. Because ACS produces a new executi

Original addressMySQL is a powerful open source relational database management system (RDBMS). It was posted on 1995 (20 ago). It uses Structured Query Language (SQL), which may be the most popular choice in database content management. The latest MySQL version is 5.6.25, released on May 29, 2015.An interesting fact about MySQL is that its name comes from the daughter "My" of Michael Widenius (the founder of MySQL). Although there are many interesting

Preface In the past decade, Oracle has become one of the world's most professional databases. For IT experts, it is to ensure that their company's productivity is improved by leveraging the powerful features of oracle. One of the most effective methods is to use ORACLE optimization. It has a lot of parameters and technologies to improve the performance of your

Reference | reference Manual | skills | performance | Chinese InnoDB Chinese reference Manual---Dog dog (heart sail) Translation 9 Performance tuning tips (performance tuning tips) 1. If Unix top or Windows Task Manager shows the service's CPU occupancy rate less than 70%, (shows that CPU usage percentage with your I s

"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 Oracle

In the past decade,OracleIt has become one of the most professional databases in the world. For IT experts, IT is to ensure that their company's productivity is improved by leveraging the powerful features of Oracle. One of the most effective methods isOracle Optimization. It has a lot of parameters and technologies to improve the performance of your Oracle database. The following describes how to optimize

not as good as Oracle ...!!!There are some children's shoes simply think that SQL Server is pediatrics, there is no technical content ... It's very simple.On these points, I don't want to spit out anything, I just want to let those friends who really know SQL Server to prove something to SQL Server.At the end of the a

Performance Tuning is not a simple task. There is no omnipotent solution at all, but you can use some basic principles to implement it. In general, performance tuning is the role of DBA. however, DBA does not have time to carefully check every change made to the stored procedure. so learning some basic tuning may help you save the effort of rewriting.CodeTime.I

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

Oracle's Optimizer:There are two types of optimizations for Oracle: The rule-based optimizer (Rbo/rule based optimizer) and the cost-based optimizer (Cbo/cost based optimizer).Sometimes, it indicates that there is an index, but the query process obviously does not use the relevant index, causing the query process to take a long time, the resource is huge, where is the problem? First, we want to determine what optimization mode the database is running

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

. 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/