Database Administrator

PostgreSQL xlog file name specification source code parsing PostgreSQL xlog, that is, WAL (Write Ahead Log), is located In the pg_xlog directory and is the Log on which PostgreSQL fully or PITR (Point In-Time Recovery) depends. Why is there WAL

Source code analysis of page Structure in PostgreSQL Source code analysis of page Structure in PostgreSQL In PG, the smallest Management Unit in disk storage and memory is page, which is also commonly referred to as block. Generally, the size of the

How to configure MariaDB replication in CentOS Linux This is a process of creating duplicate database versions. The replication process not only copies a database, but also synchronizes changes from the master node to a slave node. But this does not

MySQL understands the indexing and indexing principles [Understanding indexes] To understand indexes, you must first understand how data is stored on the hard disk. Different storage engines may adopt different measures. For example, the MySQL

Install PostgreSQL 9.4 in Linux Notes on how to install PostgreSQL 9.4 in Linux. I. Preface PostgreSQL, also known as Postgres, is a relational database management system applicable to various Linux operating systems, Windows, Solaris, BSD, and Mac

If this record exists in mysql, it is updated. If this record does not exist, the SQL statement of the record is inserted. INSERT test (id, name) values (1, 'Hello') on duplicate key update name = 'baby '; Raw data: Data after running: If

(3) mysql Optimization-SQL statement Optimization-mysqlsql Overview This article mainly introduces some common SQL Optimization Techniques SQL Optimization 1. select * from table_name where; We recommend that you change * to the required column.

Learning from the database, database Learning This time, I learned a lot about the evaluation system, learned a lot about the system of the eighth division, and learned a lot about database operations. We have been using SQL server databases when we

MySQL delayed Index Update (delay_key_write), delaykeywrite MySQL Delayed Index Update (Delayed Key Write ): The myisam Table created using the table creation option DELAY_KEY_WRITE will not write the index change data to the disk after the query

Use of MySQL view, use of MySQL ViewOverview: A view is a virtual table, also known as a derived table, because its content is derived from the query results of other tables. Although the view looks like a basic table, they are not basic tables. The

Mysql database connection and addition, deletion, modification, and query Java code implementation (PreparedStatement version), mysql database addition, deletion, modification, and query Database: create table t1(id int primary key not null

64-bit win7 Oracle11gR2 database, win7oracle11gr2 I. Description To install the Oracle11gR2 database in the 64-bit Windows 7 operating system, we first need to download the Oracle database software, which contains the 32-bit and 64-bit Oracle

Mysql database connection and addition, deletion, modification, and query Java code implementation (Statement version), mysqlstatement Database: create table t1(id int primary key not null auto_increment,name varchar(32),password varchar(32));insert

TNSPING time out/slow response, tnspingout E: \ s01 \ app \ oracle \ product \ 11.2.0 \ dbhome_1 \ BIN> tnsping CENORCLTNS Ping Utility for 64-bit Windows: Version 11.2.0.1.0-Production on 25-MAY-2015 10: 26: 59 Copyright (c) 1997,201 0, Oracle.

Relationship between innodb table level lock and lock table statement, innodbtable DDL statements only apply for intention-Level Table locks. In the lock table statement, mysql applies for mysql-Level table locks, and innodb also applies for innodb-

Question 5: What does MySQL ---------- Consecutive Numbers and numbers mean? Write a SQL query to find all numbers that appear at least three times consecutively. + ---- + ----- + | Id | Num | + ---- + ----- + | 1 | 1 | 2 | 1 | 3 | 1 | 4 | 2 | 5

Ios CoreData receives arrays containing child classes using the parent class's instance object "person" and prints the person. class. What is the result of the subclass class name? Or parent class name (resolved), coredata storage array Create

Mysql deadlock occurs when the disk is full. Today, I encountered a problem because the disk of the machine where mysql is located is full, leading to a mysql deadlock and not even querying the select statement. If I did not read the mysql Log, I

MS SQLServer Cross report (Row/column swaps), mssqlserver In MS-SQLServer 2005, you can use the combine operator to convert rows and columns. However, you must use the case when then else end statement in earlier versions. The student renewal table

With rollup and MySQLWITHROLLUP in MySQL MySQL's extended SQL has a very interesting application WITH ROLLUP. The same statistics (SUM, AVG, COUNT…) are performed based on the grouping statistics ...), Similar to the statistical functions in Oracle,