Database Administrator

In the previous article, we tested and tested the existing redis data structure (see ). We will test some common redis commands today: You need to check the data volume of the current database. There are three methods: keys *, dbsize, and info

In Mysql databases, Merge tables are somewhat similar to views. Mysql's merge engine type allows you to merge many tables with the same structure into one table. Then, you can execute the query. The results returned from multiple tables are the same

1. To access the Db2 database, first load the following lib:Db2jcc. jar, db2jcc_license_cu.jarYou can find them in C: \ Program Files \ IBM \ SQLLIB \ java.2. If the user does not have the permission to access the table, open the Db2 control center,

I encountered the following error when I restarted data of a rac today, prompting that I could not find a disk group resource named FGDG: [Grid @ srcbdb1 ~] $ Srvctl start database-d dcdbPRCR-1079: Failed to start resource ora. dcdb. db CRS-2640:

Starting from 1gR2, Oracle introduced init. ohasd and configured it in the/etc/inittab to start and manage clusterware-related resources. Pre 11R2 /Etc/inittab H1: 2: respawn:/etc/init. evmd run>/dev/null 2> & 1 H2: 2: respawn:/etc/init.css d fatal>

A redo log group can contain one or more log members, which should be stored on different disks as disk log images. The same group of Members has the same content, if you do not have multiple disks, you do not have to create multiple log members for

I will briefly describe some practical and common parameters of goldengate. 1. Parameters for Bidirectional replication to avoid circular Data Replication First, describe circular replication, which is described on the official website: In a

The error message in the log is as follows:Sun Sep 02 01:29:47 2012Global Enqueue Services Deadlock detected. More info in file/U01/app/11.1.0/diag/rdbms/zzbrac2/zzbrac21/trace/zzbrac21_lmd0_11802.trc.Sun Sep 02 01:30:30 2012Thread 1 advanced to log

Environment: Oracle 11g R2 + SQLPlus Problem: create user, a ORA-01950 error occurred while creating the table space "system" has no permission Solution: The permission issue is obvious. The permission granted after the user is created is

In the database system, the Union table (chain table) is an interesting application and provides a simple method.To share the data of the remote database, but it does not need to be as complex and troublesome as configuring the cluster or copying.

# The following options will be passed to all MySQL clients[Client]Character-set-server = utf8 ##### Default Client Connection word set. This parameter is not required if it is specified during compilation and installation.Port = 3306 ### client

Q: What is Transfer? A: It is A solution to solve the native master-slave synchronization latency of MySQL. Transfer itself is a patch on the MySQL source code. It can be used as a server Load balancer or a third-party tool to synchronously send

NLS_COMP and NLS_SORT ParametersOracle uses binary for sorting by default, which is inappropriate for Chinese sorting, for example.Use these two parameters to specify the sorting method, such as pinyin or, which may cause performance problems.The

1 ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql. sock' (2) MySQL not started 2 ERROR 1045 (28000): Access denied for user 'root' @ 'localhost' (using password: NO) The password is incorrect. Modify the

In Oracle Database Operations, accidental data deletion and table drop often occur. In the past, after this happens, developers often seek help from DBAs or administrators to use database backup and recovery to retrieve the data. From oracle 9i, 10

Currently, no database product is dedicated to cross-IDC optimization. Theoretically, the best solution adopted by the industry is based on the Paxos protocol (currently only implemented by google, google f1), today we only discuss considerations

In Oracle, copy the data of a table to another object. Usually there are two methods: insert into select and select into from. The former can copy N rows (0 to any number) from the select statement to a new table, and the latter can only copy the

An alert responds to a specific event. The alarm responds to the following event types: 1. SQL Server event: You can specify an alert to respond to one or more events. Use the following parameters to specify the event that triggers the alarm: Error

1. Environment Description:Original machine: 192.168.102.156 Oracle 10.2.0.1Target: 192.168.102.157 ORACLE 10.2.0.12. Create a table for the database.SQL> create table rmantest (id number (9 ));Table created.SQL> insert into rmantest (id) values (88

I just solved the problem of asynchronous io. I 'd like to describe how to set asynchronous IO in Oracle.First, check whether the package of asynchronous io has been installed on the operating system. If not, install it through rpm and check the