Database Administrator

Some query statements in Oracle and their execution sequence Some query statements in Oracle and their execution sequence Query condition: 1) LIKE: fuzzy query. Two Wildcards are required. %: represents 0 to multiple characters; _: identifies a

When the number of logical CPUs on windows hosts is more than 32, Database startup hangs and databasehangs Bug 9772171-Database startup hangs on Windows when machine has more than 64 cores [9772171.8] If you use a specific version of oracle db in

Introduction to Redis/Memcache proxy service Twemproxy, memcachetwemproxy Author: zhanhailiang Date:Introduction Twemproxy, also known as nutcracker, is an open-source Redis and Memcache proxy server of twtter. Function Fast. Lightweight.

Precautions for uninstalling mysql Because the database software is very complex, there are many configurations to choose whether to install Mysql or sqlserver. If you fail to install the database for the first time, and then want to uninstall it

Impdp experience ORA-39001, ORA-39000, ORA-39142, impdpora-39001Expdp/impdp because the source data version is higher than the target database version, encounter ORA-39001, ORA-39000, ORA-39142, solve only need to expdp export with the target data

[Elasticsearch] multi-field search (5), elasticsearch FieldField-centric query (Field-centric Queries) All the three problems mentioned above come from most_fields Field-centric rather than Term-centric ): it queries the Most matched fields (Most

Use oracle rownum to make the table sort Field Values continuous, using lerownum Use oracle rownum to make the table sort Field Values continuous 1. Requirements The fields in the table (eval_index) are as follows: Table Field

Compile and install mysql 5.6.21 and centos5.6.21 in Centos 1. install various dependent packages in yum [Root @ WebServer ~] # Yum-y install gcc-devel gcc-c ++-devel autoconf * automake * zlib * libxml * ncurses-devel ncurses libgcrypt * libtool *

Innodb_flush_log_at_trx_commit and sync_binlog parameters in MySQL HA architecture, innodbtrx HeartBeat + DRBD and MySQL replication are widely used by many enterprises. For data integrity and consistency, two important parameters

Application of mongodb in python-using pymongo and mongoengine, mongodbpymongo I. Preface Django is a Python Web framework that consists of an object relation (ORM), a backend controller, and a template system. MongoDB is a document-oriented

In linux, mysql enables remote access and the Firewall opens port 3306, and mysql3306 Enable mysql Remote Access Permissions By default, mysql users do not have the permission for remote access. Therefore, when the program is not on the same server

Centos6, mysql 5.5 configure master \ slave Data Synchronization backup, centos6slave Database A serves as the primary service, and database B serves as the synchronization database (note: the databases on both sides must be one-to-one, or there

Key features of InnoDB Storage engine: InnoDB Storage1. Insert BufferA. Insert BufferThe listening name can be understood as the insert buffer is part of the buffer pool. In fact, this is not the case. the InnoDB Buffer pool contains Insert Buffer

Database Backup Problems 1. If there is no database, create a database with the same name first, and then select backup. At this time, full backup is required, and component backup is not supported. If both operations are normal and the system

MySQL Case sharing: system messages and mysql Case sharing Once upon a time, a master led a group of apprentices to build a software system for the customer. One day, the customer raised a new requirement to send system messages to all users in the

A deep understanding of oracle transaction isolation and an in-depth understanding of oracle transactionsIn Oracle relational database, let's look at the following question:A transaction: select from T where id> 10 and id Transaction B: update T

Configure and modify CDB and PDB parameters in Oracle 12c, 12 cpdb  1. Configure CDB instance Parameters   The instance parameters for configuring CDB are the same as those for normal instances. You can use alter system to set initialization

Oracle source code for verifying the correctness of bank card numbers, oracle source code Create or replace function checkBankCard (p_bankcard IN varchar2)RETURN varchar2 -- RETURN OK when the request is correct; otherwise, RETURN the correct

Database paging query and database Paging 1) mysql Select * from demowhere1 = 1 LIMIT 2 and 3 Limit is used for paging. The first parameter is the row number, and the second parameter is the number of rows. 2) oracle First Select id,

Mysql_connect v/s mysql_pconnect, mysqlpconnect Original article: mysql_connect v/s mysql_pconnect Translation: mysql_connect v/s mysql_pconnect Translator: dwqs When you need to use PHP to connect to the MySQL database, you will find two database