Database Administrator

I have a business dedicated to storing LOG logs, and there are tens of millions of data every day. So I use the archive storage engine, which is faster in writing and saves space. Here is a brief introduction to the archive storage engine: 650)

The flashback query is introduced in oracle 9i. The flashback query actually uses the UNDO information to obtain the previous data. Since the UNDO space is used cyclically and the pre-transaction image cannot be permanently saved, the flashback

Objective: To test whether oracle hot backup files in windows contain spfile, control files, data files, archived logs, and non-rman recovery are available on different machines and not in the original path. Test environment: windows 2003 R2, ORACLE

Test reason With the gradual release of PXC. The Online Database Synchronization mode is gradually changed from the previous STATEMENT mode to the ROW mode. Some synchronization problems are caused by changes in the synchronization mode. Purpose To

Recently, the deadlock problem between transactions was found in the project. So I studied the MySQL lock mechanism and extended the knowledge of MVCC and other surrounding areas, I will only introduce the problems that may occur during development

For more blog posts, please note: Children without umbrellas must keep running.(Www.xuchanggang.cn) In the previous article, we used mysql-mmm to dynamically monitor the mysql database. This article uses amoeba to implement read/write splitting for

MySQL 5.5The problems encountered during a test and optimization and the solutions to the problems. For your reference.I. Table Structure OptimizationProblem 1: using different character sets for tables and fields will cause index failure.I did not

When we solve a problem for the customer today, we need to join two tables in two databases for query, with a 468 error. Of course, the two tables in the two databases have the same field data type. SelectuserTab. namefromdbName1.dbo.

This is actually a simple question. Many blogs and forums on the Internet have relevant answers. These answers are good, but they forget to indicate a small detail. This small detail also plagued me for one night. Later, I checked the relevant

The difference between a RAC database and a single instance is that multiple instances manage shared resources in a unified manner through cluster components. Therefore, you can use the original management methods for a single instance, such as

1. Disable all constraints in the database first.Select 'alter table' | table_name | 'Disable constraint' |Constraint_name | ';'From user_constraintsWhere constraint_type = 'R ';Run the command to disable all constraints.2. delete data from all

Note: note the conditions when performing the update operation. If the where clause is left blank, the full table is updated. If the table is not updated, null values are assigned. Update a single table: update tablename set col1 = value where col2

Environment: master server: IP address 192.168.1.70 Slave server: IP 192.168.1.71 Master Server Configuration: Modify permissions: Chown-R root/usr/local/mysql51 /* Chown-R mysql/usr/local/mysql51/var Chown-R mysql/usr/local/mysql51 /* Modify my.

I. general feeling: oracle is more mature and rigorous. Specific problem 1. date corresponds to the datetime type of mysql, specific to the minute, but the oracle format is YYYY-MM-DD HH24: MI: SS. Convert to_date ('yyyy-MM-DD HH: mm: ss', 'yyyy-MM-

MySQL TRIGGER) usage instructionsThe trigger program is a table-related named database object. This object is activated when a specific event occurs on the table. Mysql 5 and later support triggers. After the trigger is created, the TRG and TRN

-- ===================================================== ============== -- LOGGING mode (LOGGING, force logging, NOLOGGING) -- ===================================================== ============== 1. LOGGING modes (LOGGING, force logging, and

1. Start the editor. $ Vi file_name Open the file if the file exists. Otherwise, create a new file. 2. vi editor status The vi editor has two statuses: 1) command status You can enter various commands to edit the vi or set the vi environment. 2)

Official old saying: About Runtime Connection Load Balancing Runtime Connection Load Balancing is a feature of Oracle connection pools that can distribute client work requests processing ss the instances in an Oracle RAC database based on the Load

MySQL Performance murder -- SWAP Story: Recently, the company launched a new project about searching for a project. Its program will call a large number of SQL statements, including searching for various conditions, Fuzzy Matching, association

I. Automatic growth and automatic contraction 1. Automatic Growth By default, the size of database files can be automatically increased as needed. This can increase the file size until the disk is full. 1) Automatic growth not allowed If the