steps to optimize sql query

horizontal partition table, reduce the size of the table (Sp_spaceuse) 3, upgrade hardware 4, based on the query criteria, index, optimize the index, optimize access mode, limit the data volume of the result set. Note that the fill factor is appropriate (preferably using the default value of 0). The index should be as small as possible, using a Lie Jian index wi

Analyze the 48 causes of slow SQL query. There are many reasons for slow query speed, which are common in the following ways: 1. No index or no index is used (this is the most common problem of slow query and is a defect in programming) 2. Low I/O throughput, resulting in a bottleneck effect. 3. the

Before executing an SQL statement, Oracle needs to first check the SQL Execution Plan and then execute the SQL statement according to the execution plan. The optimizer is responsible for analyzing the execution plan, under different conditions, an SQL statement may have multiple execution plans. However, at a specific

Now the development system involves querying by page. when doing this, I am thinking, whether or not the query SQL statement can be automatically encapsulated by parameters into the ability to count the data size of the query statement that is not queried by page. for example, the general practice is: 1. first query ba

Label:ObjectiveIn the previous article, we analyzed how the query optimizer works, including: detailed operation steps of the query optimizer, analysis of filter conditions, optimization of index items, and other information.In this article we analyze the detection of several key indicator values in the course of our operation.These indicator values are analyzed

Read Catalogue Objective Technical preparation ObjectiveIn the previous article, we analyzed how the query optimizer works, including: detailed operation steps of the query optimizer, analysis of filter conditions, optimization of index items, and other information.In this article we analyze the detection of several key indicator values in the c

It is understood that most developers have a smattering of understanding of the index, limited to most of the daily work no opportunity, what is not necessary to care about, understand the index, it is really a query too slow to find the query conditions to build an index on OK, which day again a query slow, and then establish an index is, Or simply send the enti

adjust the direction of optimization to achieve the goal. The content of this module is based on the previous series of content, hoping to fully grasp the previous basic content, can enter the content of this module.Technical preparationThe database version is SQL Server2012, which is analyzed using Microsoft's previous case library (Northwind), and part of the content is also applied to Microsoft's other case library AdventureWorks.Trust the Friends

Objective In the last article, we analyzed how the query optimizer works, including: detailed operation steps of the query optimizer, filtering condition analysis, index item optimization, and so on. In this article we analyze the detection of several key metric values during the course of our operation. The operation problem of the statement is analyzed by th

Tags: query statement sql650) this.width=650; "Src=" http://images2017.cnblogs.com/blog/139239/201708/139239-20170829102801202-859313490. JPG "width=" 399 "height=" 257 "style=" border:0px; "/>Structured Query Language (SQL) is an indispensable skill in the data mining and analysis industry, and it is generally easier to learn this skill. For

The Hadoop on Azure Sqoop Import Sample tutorialtable of Contents Overview Goals Key Technologies Setup and Configuration Tutorial How to set up a SQL database How to use Sqoop from Hadoop on Azure to import SQL Database query results to the HDFS cluster in Hadoop on Azure. Summary Overview

Introduction to the Logical query processing phase from: performs a cartesian product (Cartesian product) (cross join) on the first two tables in the FROM clause, generating a virtual table VT1 on: The applies an on filter to the VT1. Only those lines that make OUTER (join): If you specify a OUTER join (relative to a cross join or (INNER join), keep the table (preserved Table: Left outer join marks the left table as a reser

There are many reasons for slow query speed in SQL Server databases. The following are common causes: 1. No index or no index is used (this is the most common problem of slow queryProgramDesign defects) 2. Low I/O throughput, resulting in a bottleneck effect. 3. the query is not optimized because no computing column is created. 4. Insufficient memory 5.

of the cool data query methods provided by LINQ to SQL, hopefully these steps will provide a good overview. To learn more LINQ expressions and new language grammars supported by the C # and VB compilers in VS2008, read the following essays I published earlier: L Automatic Properties, object initializers, and collection initializers L extension method L-Lamabada

Reference: http://blog.csdn.net/htl258/article/details/4106591,it is very useful. Use mydb go -- 1. query the logical File Name of the current database: Select file_name (1) as 'file name 1', file_name (2) as 'file name 2'; -- or query by the following statement: -- Select name from sys. database_files/* file name 1 file name 2 ------------------- -------------------- mydb mydb_log (1 row affected) */-- 2.

Tag: Style color IO using strong SP data on problemIn recent times, has been exploring the SQL Server query performance issues, of course, also aimless search for a lot of information, but also from the online great God's articles learned a lot, here, to the great God salute. It is by the great God selfless dedication of the influence of the spirit, so, the younger brother also in return, share about the se

procedures. Although Service Broker can be used entirely within SQL Server, Ado.net knows how to communicate with Service Broker to trigger this mechanism and retrieve notifications from service Broker. Note When data in SQL Server changes, the query notification allows you to buffer the data and notify you. At the. NET end, there are a number of ways to "hook i

Detailed steps and code for JDBC to connect to a SQL Server databaseThe steps for JDBC to connect to a SQL Server database are as follows:[Java]View Plaincopyprint? 1. Load the JDBC driver: Before connecting to the database, first load the driver of the database you want to connect to the JVM (Java Virtual machin

scope of consideration. We need some tools for two purposes: getting the right data and getting reasonable performance.Brief introduction: in modern information systems, the above examples are widely available. But one of the core issues that comes up is that in SQL Server (which is estimated to be in all RDBMS), there is no single execution plan that can well support all possible query conditions. You als

processing SQL Server Common steps for exceptionsSQL Server common problems are mainly caused by SQL problems, the main is the CPU is too high and blocking.First, the problem of high CPU1. Query system Dynamic View query execution time long