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preface PostgresSQL is a single example multi database. Usually, a database instance contains multiple tablespaces and databases. One tablespace can store multiple databases. In this relationship, one tablespace can contain multiple databases, but a database can only belong to one tablespace and cannot be stored across tablespaces. Table space ...

1, Background introduction In view of security considerations, the superuser of the database is generally only in the hands of DBA students. Recently, many times such a scenario has happened. Students in the business make complaints about the structure of the table. The Tucao table is locked by the system process. After investigation, it is fo ...

SUID: When s appears on the x permission of the file owner, it is called setupid bits or setupid. Its characteristics are as follows: 1.SUID permission is only valid for binary executables2. If the performer has x permission on the binary executable, the performer will have the permission of the owner of the file3. This permission is onl ...

Author: Zhang Lianzhuang, PostgreSQL R & D EngineerHe has been engaged in the development of PostgreSQL database kernel for many years and has a very in-depth research on citus.Last issue We introduced the PostgreSQL data retrieval tool: pg_reconveryThis article will take you to understand PG_ The implementation principle and design idea of ...

pg_bulkload git download address: https://github.com/ossc-db/pg_bulkload introduce PostgreSQL provides a convenient data loading tool for the copy command. The copy command comes from the PostgreSQL database. The copy command supports data loading between files and tables and data unloading from tables to files. pg_bulkload is a high-speed dat ...

PostgreSQL thinking - when can tuples be deleted? Preparatory knowledge <PostgreSQL transaction - MVCC> summary PostgreSQL supports MVCC, so when deleting, the related tuples will not and cannot be completely deleted. PostgreSQL only sets the T of the tuples involved in the Delete operation_ Xmax to indicate that the tuple has been t_ ...

Author: Song Shaohua 1, Reading guide Optimization is very important to improve the performance of the database itself in the case of hardware and non system failures. Each type of database has its own different ways to track and optimize the database. These methods include not only the optimization of the parameters of the database system it ...

This article introduces the installation and deployment steps of Greenplum. First, install Greenplum, then configure parameters, and then install the postgis extension. 1, Install and configure GreenPlum 1. Modify the corresponding machine name corresponding to / etc/hosts, which can be viewed through hostname (all nodes) 172.16.1.81 master ...

In the database system, data is the basis of everything, and the security of data is the top priority. However, data may be lost or damaged for various reasons, so data backup and recovery is particularly important.PostgreSQL is a powerful open source object relational database system. After more than 30 years of active development, PostgreSQL ...

Author: Yang Yunlong, core member of Hangao PG laboratory, Senior Database Engineer, good at HGDB, post gresql, Oracle and other mainstream databases. Introduction to table connection methods (Nested Loop/Hash Join/Merge Join/Join) database version (oracle11.2.0.4 and PostgreSQL 13.1) Environmental structureNested Loop Oracle exec ...