postgresql optimization

PostgreSQL tutorial (6): Functions and operators (2), postgresql Operators 6. Pattern Matching: PostgreSQL provides three methods for implementing pattern matching: SQL LIKE operator, closer SIMILAR TO operator, and POSIX-style regular expression.1. LIKE:Copy codeThe Code is as follows:String LIKE pattern [ESCAPE escape-character]String not like pattern [ESCAPE e

Describes the range type features and PostgreSQL features in postgresql. A new feature of PostgreSQL 9.2 is the range type range types. With this name, you can easily guess the purpose of this type. It allows you to define a value range for a column of data. This simple feature eliminates the need to define two fields to describe the start value and end value of

Detailed explanation of adding keywords in PostgreSQL syntax, detailed explanation of postgresql Add keywords in PostgreSQL syntax When PostgreSQL's background process Postgres receives the query statement, it first passes it to the query analysis module for lexical, syntax, and semantic analysis. Add keywords in the parser Syntax Parsing module. Introduction

data during transaction rollback. Transaction rollback is rare;3. As long as an index attribute is updated or the new version of the record is not on the same page as the original version, the new version of the index of all indexes will be inserted;4. the space occupied by the heap cannot be recycled through the online vacuum. The online vacuum will generate many fragments (this is also caused by the use of the heap instead of the index organization table );5. Because the index has no version

In this article, we use the MySQL 4.0.2-alpha to compare with PostgreSQL 7.2, because the MySQL 4.0.2-alpha begins to support the concept of the transaction, so this comparison is more advantageous for MySQL. We don't want to be just a performance test report, because at least from my point of view, stability and speed do not represent everything for a database. For a mature database, stability is certainly increasingly available. With the rapid impro

PostgreSQL Partition Table (partitioning), postgresql Partition Table PostgreSQL has a very useful function, partition table, or partitioning. When a TABLE has many records, tens of millions or even more records, we need to split it into subtables. A huge TABLE is like a fruit warehouse with numerous Apple peaches and oranges in disorder. It is inconvenient to fi

Global Database ranking in December: PostgreSQL steadily increases and postgresql steadily increases Author: Zhou Qi DB-Engines released the database ranking for January. Among the top 20 databases, Oracle ranked first, with Cassandra ranking 9th catching up with Redis ranking 8th, and SAP Adaptive Server ranking 14th behind Solr, SQLite declined slightly. Although the ranking of

The method for connecting and operating the PostgreSQL database in php, postgresql database. Methods for connecting to and operating a PostgreSQL database using php. This document describes how to connect to and operate a postgresql database using php. Share it with you for your reference. The method for connecting to

Xin Xing sorts out some common non-SQL operations in postgresql. Xin Xing postgresql The operations mentioned here are performed after we use psql to enter the postgresql client. They are not SQL statements, but they are usually important. Below are some common sorting operations: (1) list all databases. Use the \ l command or the \ list Command. Note that the

Create a postgresql Partition Table. Create a postgresql partition table. In postgresql, there is no partition table creation command. It is created by creating rules such as inherited tables and constraints. The steps are cumbersome and troublesome, and a method is encapsulated. To create a partition table: CREATE TABLE "odl"."user_action_fatt0" ("date_id" nume

Tutorial on implementing recursive query in PostgreSQL, postgresql Recursion Introduction I am working on a program in nilint32 (Open Source !) It is used to design and initiate surveys. The following is an example of a survey: Internally, it indicates the drop: A Survey involves many questions (question ). A series of problems can be classified into (optional) one category. Our actual data structure will

Commonly used time and date scripts in PostgreSQL tutorial, postgresql tutorial Obtain System Time Functions select now(); --2013-11-28 16:20:25.259715+08select current_timestamp; --2013-11-28 16:20:38.815466+08select current_date; --2013-11-28select current_time; --16:21:08.981171+08 Time Calculation-- Use interval Select now () + interval '2 Day'; -- 16:21:47. 610118 + 08 2 days later sele