postgresql query optimization

in the flow log table. it is estimated that it may reach 40 million records per day. using a table per day is also very large. I have read it. the MYD file size is more than 8 GB. When we query the log records in the management system, we need to perform conditional queries on several fields, and several fields have a length of 256. in the 8G table, we need to query a string. if the string cannot be found,

largest number of records in the flow log table. it is estimated that it may reach 40 million records per day. using a table per day is also very large. I have read it. the MYD file size is more than 8 GB. When we query the log records in the management system, we need to perform conditional queries on several fields, and several fields have a length of 256. in the 8G table, we need to query a string. if t

When querying database records using SQL statements, there are many different ways to query the same content.Still, although you can get the same results using a variety of methods, if you use a different approach, the execution benefits are quite different. Therefore, we have to consider carefully, if you want to query the same results, which statement to use, the implementation of the benefit is better.Th

Tags: mutual table programming Evaluation Type positioning SQL query habitual processingOriginal: http://bbs.landingbj.com/t-0-244231-1.html In any database, query optimization is an unavoidable topic. For database engineers, optimization is the most challenging task. MySQL Open source database is no exception. In fac

bytes;2. Data item: Whether there is a large number of paragraphs, the values of those fields are often updated;3. Data query SQL Condition: The column names of which data items often appear in the Where, GROUP by, and ORDER by clauses are medium;4. Data Update class SQL Condition: How many columns often appear in the WHERE clause of update or delete;5.SQL amount of statistical ratio, such as: select:update+delete:insert= how much?6. What is the magn

unfamiliar, specific usage and field meaning can refer to official website Explain-output, here need to emphasize rows is the core indicator, most of the rows small statement execution must be very fast (with exception, as described below). So the optimization statements are basically optimizing rows.Basic steps for slow query optimization0. Run first to see if it is really slow, note the setting Sql_no_ca

In the optimization query, database applications (such as MySQL) mean the operation and use of the tool. Using indexes, using explain to analyze and query, and adjusting the internal configuration of MySQL can optimize the query. Any database programmer has the following experience: a bad SQL

Tag: SEL Access SQL statement through Date diff Union All database table variableIn a TENS database search, how to improve the efficiency of the query?1 ) Database design aspects: A, to optimize the query, should try to avoid full table scan, first of all should consider the where and order by the columns involved in the index.b, you should try to avoid the null value of the field in the Where clause to jud

; +----------+-------------+------------------------------------------------+ | query_id | Duration | Query | +----------+-------------+------------------------------------------------+ | 1 | 0.02717000 | Show Tables | | 2 | 0.74770100 | Select COUNT (*) from T | | 3 | 0.00004200 | Show Prifile for Query 2 | | 4 | 34.30410100 | INSERT into T (username) select username from

database application development tools and supports Java™SQL pl and PL/SQL routines, XML editor, and other development methods. It can also be integrated with IBM's query optimization tools to Optimize Query performance. Monitoring and Management of database health and availability plan jobs. Data Studio 3.1.1 provides a Web-based monitoring tool for health an

. In the 8g table, we need to query a string. If the string cannot be found, it must be retrieved from the beginning, and the speed is too slow. The customer also needs to set conditions for query in several fields. In this way, the system availability is very low because it is usually 20 or 30 minutes long. The method I used is mainly for testing. I also read the JAVA code and use Log4j and Perf4j logs to

compilation, only 0.7 seconds to get the results. So how do you precompile, or use an existing execution plan?SQL Server has an optimization algorithm that holds the execution plan for the previous execution of the SQL statement, and all execution plans are stored in the Sys.syscacheobjects table, and if the current SQL statement matches in the cache table, then it executes the execution plan that matches to it and no longer compiles. So the solution