db2 query tuning

ObjectiveIn the previous few we analyzed a series of SQL Server-related performance tuning, which I divided into two modules.The first module focuses on the basic content of the master, a total of 6 articles to complete, covering a series of basic algorithms, the detailed analysis of how to view the execution plan, master Execution Plan optimization points, and a list of the everyday we usually write T-SQL statements will be applied operators. I belie

Introduction: DB2 databaseOfQueryThe function is a good performance in the DB2 database. The query function of the DB2 database shows the business intelligence of the DB2 database. This article mainly discusses some methods that can enable efficient execution of large querie

very important point: when unsure which type of join to use, let the MySQL optimizer automatically judge, we only need to write select * from t1,t2 where T1.field = T2.fieldThe 10.7 using where WHERE clause is used to restrict which row matches the next table or send to the customer. Unless you specifically request or check all rows from a table, the query may have some errors if the extra value is not a using where and the table join type is all or

DB2 circular query is a common problem. If we encounter a large table problem, how can we implement Circular query for large tables? The following describes how to implement the Circular query of DB2 in large tables for your reference. Requirement Description: There is a tab

---- Start The DB2 materialized query table MQT (materialized query tables) stores the results of a query. When we query related tables, DB2 automatically determines whether to use the original table or materialized

this point you will find a log file named after your native name in the Data folder in the MySQL installation directory The slow query operation is performed again at this time Open log file discovery occurrence record Later, you can only check the log file periodically to find the slow query statement. Note: after finding the slow query statement, to confi

Today, we will mainly discuss the correct use of MQT materialized query tables in the DB2 materialized view, the following is a detailed description of the main content of the correct use of the MQT materialized query table in the materialized view of the DB2 database. The MQT definition is based on the

DB2 circular query is a frequently used query method. The following describes the implementation process of circular query in DB2. If you are interested in this aspect, take a look. Requirement Description: There is a table with three fields, which are the departure time of

, where sending data accounts for 99% of the time. Still more than the initial page load time. Finally, instead of innerjoin the table with the select method to remove the relevant data, leftjoin the table data, by looping the select result set, the data is obtained separately. After the modified development environment page load time is 0.2~0.3s, the server environment is 0.4~0.5s. Although not ideal, performance is acceptable for small systems within the community. 2, MySQL DB Server is place

The following articles mainly describe the correct use of the MQT materialized query table in the materialized view of the DB2 database. If you encounter the application of the MQT materialized query table in the materialized view of the DB2 database in actual operations, however, you do not know how to solve the probl

The following articles mainly introduce the correct use of MQT materialized query tables in the materialized views of DB2 databases, if you are a beginner in the practical application of the correct use of the MQT materialized query table in the materialized view of DB2 database, you can have a better understanding thr

This article mainly describes the DB2 materialized query table, and also introduces MQT, summary table (summary), and staging table. To better describe it, we use some practical examples to show how to create and use materialized query tables. The definition of a materialized query table (MQT) is based on the results o

performance testing process. Below I will introduce three tools that are frequently used in the performance tuning process of msyql: 1. Slow query (analyze problematic SQL statements) 2. Explain (shows how mysql uses indexes to process select statements and connect tables. Can help you select better indexes and write more optimized query statements) 3. Profi

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 to analyze the operation of the statement and

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 course of our operation.These indicator values

The paging query method of DB2 is not the same as that of paging query statements in Oracle and SQL. The following describes the differences between paging query in DB2 and paging query in other databases. Oracle paging