sql performance counters

Oracle uses TRACE for SQL Performance Analysis If the SQL _trace parameter is set to true, the entire instance will be tracked, including all processes: User processes and background processes, which may cause serious performance problems and must be used with caution in the production environment. 1. perform trace ope

, converting lowercase letters to uppercase and then executing (20) Use the connector "+" connection string sparingly in Java code! (21) Avoid using not on indexed columns usually (22) Avoid using calculations on indexed columns (23) Replace > with >= (24) Replace or with union (for indexed columns) (25) Replace or with in (26) Avoid using is null and is not NULL on an indexed column (27) Always use the first column of an index (28) Replace union with Union-all (if possible)

dizzy, I can ensure that the database will also be dizzy. In addition, execution plans can be reused. The simpler SQL statements, the higher the possibility of reuse. Complex SQL statements must be re-parsed as long as there is a change in the character, and then put this pile of garbage in the memory. We can imagine how low the database efficiency will be. 4. Use "temporary table" to save intermediate res

It is often asked whether the conditional writing sequence of the Where clause in oracle has an impact on SQL Performance. My intuition is that if this order has an impact, Oracle should have been able to achieve automatic optimization for a long time, however, there has been no conclusive evidence in this regard. Articles found on the Internet generally think that there is no impact in the RBO optimizer mo

Always want to find some of the authoritative reference for SQL statement performance debugging, but there is no reference may not be able to do the debugging work. I am convinced that the experience gained in practice is the most precious, and that book knowledge is only a guide. This article is from "Inside Microsoft SQL Server 2008", the experienced master des

Many of my friends may be making mistakes in performance optimization as described below. If you have any need, please refer to the mistakes in SQL Server query performance optimization to get out of the index. Many of my friends may be making mistakes in performance optimization as described below. If you have any nee

In a large database, performance has become one of the focuses of attention. How to Make the efficient and effective operation of the database become an issue that must be considered by database administrators and developers. Performance is the measure of efficiency when one or more applications run in the same environment. Performance is usually expressed by res

volume of the two will be significantly different. Try to be less orWhen there are multiple conditions in the WHERE clause to "or" coexist, the MySQL optimizer does not have a good solution to its execution plan optimization problem, coupled with MySQL-specific SQL and Storage layered architecture, resulting in poor performance, often using union ALL or U Nion (when necessary) in lieu of "or" will have a b

Always want to find some of the SQL statement performance debugging authoritative reference, but there is no reference may not be able to do debugging 2 of the work. I am convinced that the experience gained in practice is the most precious, and that book knowledge is only a guide. This article is from "Inside Microsoft SQL Server 2008", the experienced master de

our goals. For SQL statements, there is only one way to achieve the above 2 goals, that is to change the SQL execution plan, let him try to "less detours", as far as possible through a variety of "shortcuts" to find the data we need to achieve "reduce the number of IO" and "reduce CPU computing" target Common pitfalls Count (1) and count (Primary_key) better than COUNT (*)Many people

planOnce we have identified the optimization goals, we need to identify ways to achieve our goals. For SQL statements, there is only one way to achieve the above 2 goals, that is to change the SQL execution plan, let him try to "less detours", as far as possible through a variety of "shortcuts" to find the data we need to achieve "reduce the number of IO" and "reduce CPU computing" targetCommon pitfalls1.c

The above article mentioned win Performance Monitor is a necessary tool for monitoring database performance, Next I will give you some common monitoring indicators, in fact, is nothing more than disk, CPU, memory and other hardware operating indicators as well as the database itself, such as lock Ah, the number of user connections Ah, There is the need to pay attention to the parameters of their own busines

This article discusses how to improve the performance of SQL Server databases. BKJIA database channel recommends "getting started with SQL Server" to help you better understand SQL Server databases. 1. SQL Server System database Introduction

FiddlerFiddler is one of the most powerful Web debugging tools that can record HTTP and HTTPS requests from all clients and servers, allowing you to monitor, set breakpoints, and even modify input and output data. The use of Fiddler is a great help in diagnosing and analyzing problems, both for development and for testing.: Http://www.telerik.com/download/fiddlerOperating principles and instructions for use can be consulted: http://www.cnblogs.com/TankXiao/archive/2012/02/06/2337728.htmlOf cours

The ORACLE tutorial is: Oracle-based high-performance dynamic SQL program development. Abstract: This article summarizes the development of dynamic SQL programs and provides several development skills based on the actual development experience of the author.Keywords: dynamic SQL, PL/

Tags: image syntax According to the purpose BST text editor condition plan same The source of this article: http://www.cnblogs.com/wy123/p/7190785.html (It is not the original works right to retain the source, I my book still far to reach, just to link to the original text, because the following may exist some errors to amend or supplement, without him) A performance issue was first thrown, and a few days ago, a stored procedure with a very low produ

People often ask Whether the conditional writing sequence of the where clause in Oracle has an impact on SQL performance does not affect my intuition, because if the order has an impact, Oracle should have been able to achieve automatic optimization for a long time, however, there has been no conclusive evidence in this regard. Found on the InternetArticleGenerally, it is considered that there is no impact

highly efficient, but because of its limited statistics, the optimizer's work process is more likely to deviate. For complex multiple table joins, on the one hand because of its optimizer limited, and also in the Join this aspect of the effort is not enough, so performance from Oracle and other relational database predecessors still have a certain distance. However, if it is a simple single table query, this gap will be very small even in some scenar

Brief introduction There are a number of sources available for how to tune your database systems and applications. DB2 tuning techniques such as OLTP applications (previously published in the ibm®db2® Developer's Garden) some suggestions from table space and index design to buffer pool memory allocation are given through the use of transaction and data parallelism and analysis of query scenarios. These aspects are the basics of performance tuning. H

The source of this article: http://www.cnblogs.com/wy123/p/7106861.html(It is not the original works right to retain the source, I my book still far to reach, just to link to the original text, because the following may exist some errors to amend or supplement, without him)Recently encountered in SQL Server several times the developer submitted the performance problem of