Database Administrator

MySQL backup tool-mysqlhotcopy Mysqlhotcopy uses lock tables, flush tables and cp or scp to quickly back up the database. it is the fastest way to back up a database or a single table. It is a physical backup, but it can only be used to back up the

Java Oracle Stored Procedure Problems PL/SQL is an extension of Oracle's standard database language. ORACLE has integrated PL/SQL into ORACLE servers and other tools, in recent years, more developers and DBAs have started to use PL/SQL. This article

Node where RAC Archive log is written incorrectly Multiple customers have asked several times that archive logs of node2 In the RAC environment are written to the archive path of node1. This problem causes some customers to be unable to read logs

How to delete a database in Oracle 11 without using DBCA This short tutorial will show you how to delete a database from Oracle 11 without using DBCA (Database Configuration Assistant. 1-SID of the imported database, if not defined Export

Use of ISNULL function in SQLserver and IFNULL function in Mysql, isnullifnull This article introduces the isnull function in SQL server and ifnull function in mysql, and introduces the specific usage and differences between the two. If you are

Using Gearman to synchronize data from MySQL to Redis, gearmanredis For data that frequently changes, if you still use the traditional static cache method (Memocached, File System, and so on) to display data, there may be a huge overhead in cache

Oracle performance optimization operation 11: try to match the like clause at the front end. oracle clause Because the like parameter is frequently used, if the like clause can be indexed, the query efficiency will be greatly improved. Example:

Database Optimization-vertical segmentation and Application in actual projects, vertical segmentation I was in charge of a project (China Telecom BDC project), and the purchased Database hardware was a small unit of P590. After the stress test, the

Oracle Performance Optimization Operation 9: shielding useless indexes and optimizing oracle Performance Example of "oracle performance optimization operation 8" In actual queries, there are also queries involving DisposalCourseFlag = 6. If the

How a single commit and multiple commit affect the IOPS of the system.Zookeeper The name and sensitive number desensitization statement in this article: In order to protect personal privacy, the real name of the expert is desensitized and replaced

MySQL slow Query Slow query (slow log)It can help us locate specific SQL statements for SQL statement optimization. For example, slow query logs record the SQL statements whose execution time exceeds the given value, so as to locate the

MySQL_05-Select query details, mysql_05-select SQL query details 1. Orderby A) Order by field asc | desc B) Allow sorting of multiple fields: first sort by the first field. If not, then sort by the second field. And so on. 2. Limit (Limit the number

Oracle constraints (constraints) affect the query plan, oracleconstraintsOriginal article: http://www.oracle.com/technetwork/issue-archive/2009/09-may/o39asktom-096149.htmlHow constraints in oracle affect the query planIt is generally considered

In Oracle DB 12.1.0.2, SYS. ALL_CONSTRAINTS and SYS. ALL_CONS_COLUMNS are defined, SYS. ALL_CONSTRAINTS is defined as follows:   CREATE OR REPLACE VIEW ALL_CONSTRAINTS ASselect OWNER, CONSTRAINT_NAME, CONSTRAINT_TYPE, TABLE_NAME,

Oracle modifies session, processes, and oracleprocesses1. Check the values of the two parameters sqlplus/nologsql> conn/as sysdbasql> select count (*) from v $ session; here we can see the current session count SQL> select count (*) from v $ process;

SQL Server --- process Deadlock Detection and removal, SQL Server ---SQLServer --- process Deadlock Detection and Removal Recently, I encountered such a situation in the evaluation system of a college. When the number of data centers reaches the

Oracle transaction principle Inquiry 1 -- oracle Core Technology Reading Note 5, oracle1 -- oracle 1. Conflict Resolution Suppose there is a system that only has two users: You and me, and we are constantly modifying and querying a small part of the

Oracle environment variables and identifiers that you don't pay much attention to, and oracle environment variablesSign (?) Represents the ORACLE_HOME Environment VariableEg:SQL> ALTER TABLESPACE TEMP ADD DATAFILE '? /Dbs/temp02.dbf 'size 200 M;Sign

Install redis and centosredis in centos 6.5 Version: redis-2.8.19.tar.gz Check whether the following dependencies are installed. If not, install them first. Otherwise, an exception occurs. Yum installgcc-c ++ Yum install-y tcl.   1. Obtain the

OPatch reports Prerequisite check CheckMinimumOPatchVersion failed, opatch Prerequisite check CheckMinimumOPatchVersion failed Symptom: [oracle@db01 18522509]$ /DBSoft/Product/11.2.4/db_1/OPatch/opatch applyOracle Interim Patch Installer version 11