PostgreSQL

The PostgreSQL control file is named Pg_control under the $pgdata/global directory. The following three sections of information are recorded in the control file: 1. Static information generated when INITDB: Pg_control version number:922Catalog

Objective The project uses the MyBatis call PostgreSQL stored procedure (custom function) related operations, because the PostgreSQL has an array type, so there is a custom function of the entry is an int array, in the form of: Copy Code

Background PostgreSQL 9.6 Dynamic View pg_stat_activity new Wait_event_type, wait_event wait event display. When the session is in a waiting state, wait_event and Wait_event_type are Non-null, indicating the type the session is waiting for.

Goal: Make POSTGRESQL a universal, cross-platform database, a favorite tool for developers.To do, of course, POSTGRESQL itself does not need us to do now. A database needs to be supported by good peripherals to become a popular, universally-used

设置数据目录，一般使用环境变量 PGDATA 指向数据目录的根目录。目录的初始化是使用 initdb 来完成的，-D 后面加上自定义目录的路径Initdb-d/tmp/testpostgres2/data完成后在设置的目录下就会生成一些配置文件。配置日志：PostgreSQL有3种日志，分别是pg_log（数据库运行日志）、pg_xlog（WAL 日志，即重做日志）、pg_clog（事务提交日志，记录的是事务的元数据）pg_log默认是关闭的，需要设置参数启用此日志。Log_statement

Business extension fields are often stored in the PostgreSQL database using JSON-formatted data, whereas MyBatis defaults to Typehandler that do not implement JSON-type fields, so we typically need to customize the Typehandler of MyBatis.The

Retrieves the ID of the deadlock process SELECT * from pg_stat_activity WHERE datname= ' database name ' and waiting= ' t ';Find the value of the PID column usedOrSelect OID from Pg_class where relname= ' may lock table table '--oid is the ID

Linux is not a problem at all, but it is cumbersome under the Windows operating system. The environment variable needs to be added path path: C:\Program Files (x86) \postgresql\9.3\bin Add postgres System User: Computer------Local

PostgreSQL has the following 3 configuration files, which can be found using find.If the normal user looks under the Linux folder, it may not be found because of insufficient permissions. You can use Find lookup from root.[Email protected]/]#

View---toolwindows---DatabaseDatabase page in the upper left corner of the green "+", DataSource select PostgreSQL, set the address, user name, passwordIf the driver file is missing such as:Click on the first red line "PostgreSQL", enter the page

Vacuum commands exist in two forms, vacuum and vacuum full, and the difference between them is shown in the following table: No vacuum VACUUM VACUUM full After deleting large amounts of data Simply

Initdb will specify a PGDATA directory, which is where PostgresQL stores data, such as:/var/lib/pgsql/10/data.====== Display Data Catalog1. Enter PsqlSudo-u Postgres Psql2. Locate the Data directorypostgres=# SHOW data_directory;Data_directory-------

JPA Dependency org.springframework.boot spring-boot-starter-data-jpa org.springframework.data spring-data-jpa Domain class package

Objective: Although the author has released the Docker version, it can be built with just one click (One command). But in the spirit of learning or to do their own toss over, a key although good but not clear ah. The official has

1. Installation Environment InstructionsThe author in this machine under the virtual machine installation, the database has been installed.ubuntu16.04 x64Postgresql:9Wildfly102. Preparation before installationDownload the necessary packages

Recently due to business needs and some JSON storage query needs, the new application cut to pgsql up, just cut, can be normal use, but occasionally will comeJava Connection Pgsql occasionally this error

1. Environment Preparation:A) Install PowerDesigner, take PowerDesigner15.1 as an exampleb) Install Java JDK, take jdk-7-windows-i586 as an examplec) Download the Postgressql JDBC driver jar package, taking Postgresql-8.1-415.jdbc2.jar as an

After using gin () to create a full-text index, the query is still very efficient when the result set is large, although there is a walk index.Update_time is not null and plainto_tsquery (' driver ') @@ keyword_participle ORDER by Avg_mon_search

Cause of the error:I have redefined a self-increment table ("ID serial Primark key") in the SQL file of the table, but there is an INSERT statement in the SQL file that initializes the data, which is the ID self-increment field, not starting from

To install ReadLine, Readline-dev the development package, or turn off the ReadLine feature using the--without-readline option.#yum install readline;#yum install Readline-dev;ReadLine is the command line editor, close, you can not edit the command