Database Administrator

Explanation of the Redis configuration file Parameters of the Redis configuration file: 1. Redis does not run as a daemon by default. You can modify this configuration item and use yes to enable the daemon. Daemonize no 2. When Redis runs as a

How to delete historical data generated by statspack When $ Oracle_HOME/rdbms/admin/spauto is used. after SQL creates a default job, snapshots are collected every hour in the database, so that you can use $ ORACLE_HOME/rdbms/admin/spreport at any

MySQL slow Query Brief description: To analyze the query performance of MySQL statements, in addition to using the EXPLAIN command to output the execution plan, MySQL can also record the statements whose query exceeds the specified time, the SQL

ORA-00494 enqueue [CF] held for too long troubleshooting Today, the application staff responded by phone that an exception occurred after a backup database was added to the tablespace. This problem occurs when the database can be queried, but the

Oracle 11g audit files Audit: The audit option enabled by default for Oracle 11g. The default value of AUDIT_TRAIL is DB, which indicates that audit data will be recorded in the base table of the audit dictionary in the database. In Oracle 10 Gb,

Record Oracle bad block Repair Process The following error was reported during RMAN cold backup yesterday when I received a backup call from my colleague. A tablespace backup failed.RMAN-00571: ========================================================

Mha vip switch script MHA can ~ Automatic Fault Detection and Failover within 30 seconds, suitable for high availability and high data integrity requirements. To achieve seamless switching, you also need to rely on VIP drift. The commonly used

Data structure, data structure and AlgorithmLinear table A linear table is a typical linear structure. The basic feature is that the data elements in a linear table are ordered and limited. In this structure: ① There is a unique data element called "

The Operating System gateway settings do not affect 11.2 RAC and 11.2rac. By default, 11.2 does not ping the gateway to check whether the public network is available. Therefore, the gateway setting does not affect 11.2 RAC. After 11.2, you can

Database and database LearningRegister log files Basic PrinciplesThe registration order is strictly in the time order of parallel transaction executionThe log file must be written before the databaseWrite a log file: indicates the modified log

Mysql carpet-based learning (I)-Mysql overall architecture introduction, mysql carpet-Based Learning Recently, I feel that my skills have been learned along with my work, and I feel that I have never mastered some knowledge, I plan to

Mysql Study Notes 2 (Table constraints) and mysql Study NotesOperation table Constraints Integrity is the accuracy and consistency of the index data, and integrity check is to check the data accuracy and consistency. The mysql database management

Remotely and quickly kill a session !, Remotely kill a session!Today, A developer called A (not to mention the information) asked in the group:The table is stuck when a large amount of data is inserted. I found that the table is locked and the

Mysql architecture arrangement, mysql Architecture MySQL is composed of data files and database instances. It is a single-process, multi-thread architecture.Database Files: a collection of physical operating system files or other files. In mysql,

Error Code: 1305. FUNCTION student. rand_string does not exist, randstring 1. Error description 13: 52: 42 call new_procedureError Code: 1305. FUNCTION student. rand_string does not exist0.000 sec 2. Error cause Create definer = 'root' @

Insert a new column after specifying a column in MySQL, and insert a column in mysql.ALTER [ONLINE | OFFLINE] [IGNORE] TABLE tbl_nameAlter_specification [, alter_specification]...Alter_specification:Table_options| ADD [COLUMN] col_name

MySQL Study Notes _ 9_MySQL Advanced Operations (on) and study notes _ 9_mysql MySQL Advanced Operations (I) I. MySQL table replication Create table t2 like t1; # copy the table structure. t2 can learn all the table structures of t1. Insert into t2

Game test-database Statement 1, test database Statement 1Select id, name, energy from db_name where engrgy between '000000' and '000000'To sort the output content once, use order by asc to change from small to large to desc.Select id, name, energy

Query the locked process information of MySQL in Linux.1. Problem Description When using the database, tables may be locked, causing timeout when other processes access the same table. Specifically, use the following command in MySQL: SHOW

Duplicate Emails, duplicateemails Write a SQL query to find all duplicate emails in a table named Person. + ---- + --------- + | Id | Email | + ---- + --------- + | 1 | a@ B .com | 2 | c@d.com | 3 | a@ B .com | + ---- + --------- + For example,