search
HomeDatabaseMysql TutorialHow to write and optimize SQL Server stored procedures

How to write and optimize SQL Server stored procedures

Mar 19, 2017 am 10:51 AM
phpphp tutorialVideo tutorial

[Introduction] In the development process of database, we often encounter complex business logic and operations on the database. At this time, SP will be used to encapsulate the database operations. If there are many SPs in the project and there are no certain standards for writing, it will make it difficult to maintain the system in the future and make it difficult to understand the logic of the large SPs. In addition, during the development process of the database, complex problems will often be encountered. For business logic and database operations, SP will be used to encapsulate database operations at this time. If the project has many SPs and the writing is not standardized, it will make it difficult to maintain the system in the future and make it difficult to understand the logic of the large SPs. In addition, if the amount of data in the database is large or the project has high performance requirements for the SPs, you will encounter It is a problem of optimization, otherwise the speed may be very slow. Through personal experience, an optimized SP is even hundreds of times more efficient than a SP with poor performance.

Details:
1. If developers use Tables or Views from other libraries, they must create Views in the current library to implement cross-library operations. It is best not to use them directly. "databse.dbo.table_name", because sp_depends cannot display the cross-database table or view used by the SP, which is inconvenient for verification.

2. Before submitting SP, developers must have used set showplan on to analyze the query plan and conduct their own query optimization checks.

3. To improve program operation efficiency and optimize applications, you should pay attention to the following points during the SP writing process:


(a) SQL usage specifications :

i. Try to avoid large transaction operations and use the holdlock clause with caution to improve system concurrency.


ii. Try to avoid repeatedly accessing the same table or tables, especially tables with a large amount of data. You can consider extracting data into a temporary table based on conditions first, and then making a connection.


iii. Try to avoid using cursors, because cursors are less efficient. If the data operated by the cursor exceeds 10,000 rows, it should be rewritten; if a cursor is used, try to avoid cursor loops. Then perform the table join operation.


iv. Pay attention to the writing of where clauses. The order of statements must be considered. The order of conditional clauses should be determined according to the index order and range size. Try to make the field order consistent with the index order and range. From big to small.


v. Do not perform functions, arithmetic operations or other expression operations on the left side of "=" in the where clause, otherwise the system may not be able to use the index correctly.


vi. Try to use exists instead of select count(1) to determine whether a record exists. The count function is only used when counting all rows in the table, and count(1) is more convenient than count(*). Efficient.


vii. Try to use ">=" instead of ">".


viii. Pay attention to the replacement between some or clauses and union clauses


ix. Pay attention to the data types of connections between tables and avoid differences between different types of data. Connection.


x. Pay attention to the relationship between parameters and data types in stored procedures.


xi. Pay attention to the data volume of insert and update operations to prevent conflicts with other applications. If the amount of data exceeds 200 data pages (400k), the system will upgrade the lock, and the page-level lock will be upgraded to a table-level lock.


(b) Index usage specifications:

i. The creation of indexes should be considered in conjunction with the application. It is recommended that large OLTP tables should not exceed 6 indexes.


ii. Use index fields as query conditions as much as possible, especially clustered indexes. If necessary, you can use index index_name to force the index to be specified


iii. Avoid pairing Perform table scan when querying large tables, and consider creating new indexes if necessary.


iv. When using an index field as a condition, if the index is a joint index, then the first field in the index must be used as the condition to ensure that the system uses the index, otherwise the The index will not be used.


v. Pay attention to index maintenance, periodically rebuild indexes, and recompile stored procedures.


(c) Tempdb usage specifications:

i. Try to avoid using distinct, order by, group by, having, join, cumute , because these statements will increase the burden on tempdb.


ii. Avoid frequent creation and deletion of temporary tables and reduce the consumption of system table resources.


iii. When creating a temporary table, if the amount of data inserted at one time is large, you can use select into instead of create table to avoid logs and improve speed; if the amount of data is not large, in order to ease the system For table resources, it is recommended to create table first and then insert.


iv. If the temporary table has a large amount of data and needs to be indexed, the process of creating the temporary table and indexing should be placed in a separate sub-stored procedure to ensure that the system can easily It is better to use the index of the temporary table.


v. If temporary tables are used, all temporary tables must be explicitly deleted at the end of the stored procedure. First truncate the table, and then drop the table. This can avoid long-term locking of system tables. .


vi. Use caution when querying and modifying connections between large temporary tables and other large tables to reduce the burden on system tables, because this operation will use the tempdb system table multiple times in one statement.


(d) Reasonable algorithm use:


Based on the SQL optimization technology mentioned above and the SQL optimization content in the ASE Tuning manual, combined with practical applications, multiple algorithms are used for comparison to obtain the method that consumes the least resources and is the most efficient. Specific ASE tuning commands are available: set statistics io on, set statistics time on, set showplan on, etc.

The above is the detailed content of How to write and optimize SQL Server stored procedures. For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
How do you handle database upgrades in MySQL?How do you handle database upgrades in MySQL?Apr 30, 2025 am 12:28 AM

The steps for upgrading MySQL database include: 1. Backup the database, 2. Stop the current MySQL service, 3. Install the new version of MySQL, 4. Start the new version of MySQL service, 5. Recover the database. Compatibility issues are required during the upgrade process, and advanced tools such as PerconaToolkit can be used for testing and optimization.

What are the different backup strategies you can use for MySQL?What are the different backup strategies you can use for MySQL?Apr 30, 2025 am 12:28 AM

MySQL backup policies include logical backup, physical backup, incremental backup, replication-based backup, and cloud backup. 1. Logical backup uses mysqldump to export database structure and data, which is suitable for small databases and version migrations. 2. Physical backups are fast and comprehensive by copying data files, but require database consistency. 3. Incremental backup uses binary logging to record changes, which is suitable for large databases. 4. Replication-based backup reduces the impact on the production system by backing up from the server. 5. Cloud backups such as AmazonRDS provide automation solutions, but costs and control need to be considered. When selecting a policy, database size, downtime tolerance, recovery time, and recovery point goals should be considered.

What is MySQL clustering?What is MySQL clustering?Apr 30, 2025 am 12:28 AM

MySQLclusteringenhancesdatabaserobustnessandscalabilitybydistributingdataacrossmultiplenodes.ItusestheNDBenginefordatareplicationandfaulttolerance,ensuringhighavailability.Setupinvolvesconfiguringmanagement,data,andSQLnodes,withcarefulmonitoringandpe

How do you optimize database schema design for performance in MySQL?How do you optimize database schema design for performance in MySQL?Apr 30, 2025 am 12:27 AM

Optimizing database schema design in MySQL can improve performance through the following steps: 1. Index optimization: Create indexes on common query columns, balancing the overhead of query and inserting updates. 2. Table structure optimization: Reduce data redundancy through normalization or anti-normalization and improve access efficiency. 3. Data type selection: Use appropriate data types, such as INT instead of VARCHAR, to reduce storage space. 4. Partitioning and sub-table: For large data volumes, use partitioning and sub-table to disperse data to improve query and maintenance efficiency.

How can you optimize MySQL performance?How can you optimize MySQL performance?Apr 30, 2025 am 12:26 AM

TooptimizeMySQLperformance,followthesesteps:1)Implementproperindexingtospeedupqueries,2)UseEXPLAINtoanalyzeandoptimizequeryperformance,3)Adjustserverconfigurationsettingslikeinnodb_buffer_pool_sizeandmax_connections,4)Usepartitioningforlargetablestoi

How to use MySQL functions for data processing and calculationHow to use MySQL functions for data processing and calculationApr 29, 2025 pm 04:21 PM

MySQL functions can be used for data processing and calculation. 1. Basic usage includes string processing, date calculation and mathematical operations. 2. Advanced usage involves combining multiple functions to implement complex operations. 3. Performance optimization requires avoiding the use of functions in the WHERE clause and using GROUPBY and temporary tables.

An efficient way to batch insert data in MySQLAn efficient way to batch insert data in MySQLApr 29, 2025 pm 04:18 PM

Efficient methods for batch inserting data in MySQL include: 1. Using INSERTINTO...VALUES syntax, 2. Using LOADDATAINFILE command, 3. Using transaction processing, 4. Adjust batch size, 5. Disable indexing, 6. Using INSERTIGNORE or INSERT...ONDUPLICATEKEYUPDATE, these methods can significantly improve database operation efficiency.

Steps to add and delete fields to MySQL tablesSteps to add and delete fields to MySQL tablesApr 29, 2025 pm 04:15 PM

In MySQL, add fields using ALTERTABLEtable_nameADDCOLUMNnew_columnVARCHAR(255)AFTERexisting_column, delete fields using ALTERTABLEtable_nameDROPCOLUMNcolumn_to_drop. When adding fields, you need to specify a location to optimize query performance and data structure; before deleting fields, you need to confirm that the operation is irreversible; modifying table structure using online DDL, backup data, test environment, and low-load time periods is performance optimization and best practice.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SAP NetWeaver Server Adapter for Eclipse

SAP NetWeaver Server Adapter for Eclipse

Integrate Eclipse with SAP NetWeaver application server.

PhpStorm Mac version

PhpStorm Mac version

The latest (2018.2.1) professional PHP integrated development tool

Atom editor mac version download

Atom editor mac version download

The most popular open source editor

Safe Exam Browser

Safe Exam Browser

Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.