Database Administrator

MySQL compilation, installation, and user management MySQL user password modification:1. mysqladmin-u USERNAME-h HOSTNAME password 'new _ pass'-p2. set password for 'username' @ 'host' = PASSWORD ('new _ pass ');3. UPDATE mysql. user set password =

Comparison of exp and expdp export performance Performance Comparison between General EXP mode, direct EXP path mode, and EXPDP Export 1. First, export the normal path of EXP: Exp bkjia/zhejiang file =/data1/zj_regular.dmp buffer = 20480000 The

Compile MySQL source code using Eclipse-cpp in Ubuntu 1. Download The eclipse-cpp-mars-2-linux-gtk-x86_64.tar.gz package, decompress it in Ubuntu, and run it. Jdk errors may occur because jdk is not installed or the jdk version is too low. Jdk1.8

Problems arising from over-using DBLINK for system integration Excessive use of DBLINK for system integration may cause many problems, mainly due to the following: 1. A large amount of database resources are consumed; Each time the local system

Mysqldump -- master-data parameter for Fast deployment of master-slave Replication Mysqldump -- help-- Master-data [= #] This causes the binary log position and filename to beAppended to the output. If equal to 1, will print it asChange master

Setting a large memory page on Linux solves the problem that the kswapd0 process consumes cpusys in transition. Environment: SLES11 SP4 + Oracle 11.2.0.4After a new test database was set up and ran for about two days, it was found that a process

MySQL trigger Update triggers Insert failure To display the historical records of tables with status updates only, you need to create a trigger in the original table to write the updated content to another table at the same time. So the test  --

Create an instance in MongoDB master-slave mode For databases, the master-slave architecture mode is often used to ensure data security and high availability. for Mongodb, this article describes how to build a simple Mongodb master-slave

Oracle Partition Table online redefinition field not null Oracle uses DBMS_REDEFINITION to redefine a table online. It synchronizes data to an intermediate table in the new structure based on the materialized view, and then implements it by renaming

SQL Server 2014 SP1 NOLOCK command interrupted In the Cumulative Update #6 Update for SQL Server 2014 SP1, The NOLOCK command is interrupted. Therefore, databases dependent on the NOLOCK command may experience congestion or deadlocks in other places.

Redis Master/Slave replication failed (master_link_status: down) The master_link_status: down prompt is displayed when configuring redis master-slave replication today. First, open the redis. conf configuration file of slave and check whether the

Redis master-slave replication network transient disconnection Record several interesting usage first1. Repeated executionThe-r option repeats the number of times specified by a command.-I: Set the interval between command execution.For example, you

DataGuard how to transmit Redo to Standby DataGuard transfers redo to standby and then applies the redo on standby to ensure data consistency between the two.The lgwr process is used to transmit redo logs. In the lgwr transfer mode, the lgwr process

Error Sanity check failed during mysqlbinlog backup When I reviewed MySQL binary logs today, I found some problems:Mysqlbinlog-uroot-proot/usr/local/mysql/data/node1.000004 -- start-datetime = "13:30:00" -- stop-datetime = "13:45:00"> a. SQL ERROR:

Two ways to export a table (DMP file) from Oracle Oracle exports tables (DMP files) in two ways: Method 1: export using PL/SQL Developer:Menu Bar ----> Tools ----> Export Tables, for example, you can set relevant parameters: Method 2: Use the cmd

MySQL alter table storage engine (myisam innodb) View the supported database engines and default database engines of the current MySQL database 123456789101112131415 mysql> show engines;+--------------------+---------+-------------------

Use dbms_transaction to obtain the transaction ID The most common way to find the current transaction ID and rollback segment is to execute the following SQLSQL> select xidusn, xidslot, xidsqn from v $ transaction, v $ session where saddr = ses_addr;

Error Caused by Double Type Precision Scenario Description R & D colleagues asked me to round the value of a double type field to keep two decimal places. In mysql, round (col, 2) can be rounded to five and keep two decimal places, but the magic

Automatic parallelism in Oracle 11gR2 In Oracle 11.2.0.2, automatic parallelism can be used only when I/O statistics are collected. When parallel_degree_policy is set to auto, the Oracle database determines whether to use Parallelism Based on the

Hadoop 2.x detailed steps for building a pseudo-distributed environment, hadoop2.x This article describes in detail the entire process of Hadoop 2.x pseudo-distributed environment construction by combining text and text for your reference. The