Database Administrator

Oracle redo log Oracle Redo Log recordFor all database changes, when you perform DML or DDL operations, oracle records the database changes to the redo log. The primary purpose of Redo Log is to use the Redo Log to recover an instance or media

Start notes for Flashback database To build an Oracle database for the testing department, you must meet the requirements that can often roll back the entire database to a certain time point. A simple method is to use one of Oracle's flash back

Oracle Error: ORA-12514 This should be a series of ORA-00119 (TNS: the listener cannot identify the Service requested in the connection descriptor. After investigation, it was found that the dynamic registration of Oracle instances to Listener was

Add or delete a log group at 10 Gb in Oracle This error was found in the alert Log during routine inspection. Thread 1 cannot allocate new log, sequence 319708 Checkpoint not complete This is actually a common error. Generally, it is because when

Oracle Database write process (DBWR/DBWn)Oracle Database write process (DBWR/DBWn) database write process replication writes data in the dirty data zone of the database high-speed buffer to the data file. In an Oracle instance, a maximum of 10

Introduction to Oracle Database and InstanceIntroduction to Oracle Database and Instance Database: it consists of a series of files stored on the disk. These files are used to store data. Database instance: it consists of a series of memory

MySQL version upgrade record /*************************************** **************Upgrade MySQL 5.6.19 to 5.6.21 **************************************** *************/Backup is required before upgrade! ---- 1. view the data directory location of

Case of configuring static listening to resolve ORA-12514 errorsToday, when I configured Linux for DG, I encountered a problem: tnsname. ora file configuration is normal, tnsping is normal, listening is normal, but still reports ORA-12514 error: SQL>

Some RAC services are resolved in the UNKOWN state. After restarting the RAC server, we found that: Rac1-> crs_stat-tName Type Target State Host------------------------------------------------------------Ora... CRM. cs application online unknown rac1

Install Oracle 11g RAC in Linux-DNS Configuration The IP address of the Linux-DNS server is 192.168.2.98.The DNS address to be configured is 192.168.2.212, which must be used by no one. Otherwise, an error will be reported when installing grid. 1.

MySQL multi-log table result set splicing Stored Procedure Generally, MySQL logs only record the log information of the current day. If you need to view the log information within January, You Need To splice the result set of the daily log table,

Set RowCount and top n, setrowcounttop Sometimes, if n in top n is a variable, you need to use: declare @count1 intset @count1 = 8select top (@count1) * from MyTable If set RowCount is used, the same effect can be achieved. declare @count1 intset

This server supports both version 661 and earlier. The downgrade path is not supported ., 661 downgradeThis server supports both version 661 and earlier. The downgrade path is not supported.Environment: SQL Server 2008 R2. problem: the error "this

ORACLE Database FAQ summary, oracle FAQ Summary Prompt when submitting the transaction (solution for locking the database by a user) Select object_id, session_id, locked_mode from v $ locked_object; Select t2.username, t2.sid, t2.serial #, t2.logon

Archive logs and oracle archive logs RACSqlplus/as sysdbaSQL> alter system set cluster_database = false scope = spfile; -- in node1SQL> create pfile = '/opt/oracle/pfile_20120301' from spfile; -- in node1SQL> alter system set log_archive_format =

Database startup (below), Database startup ( 3. STARTUP This command completes the three steps of creating an instance, installing an instance, and opening a database. At this time, the database makes the data document and the re-log document online,

[MongoDB] The description of index (1), mongodbdescription From this blog, we start to talk about the index in mongo Database, which is similar to the traditional database. generally speaking, if the index need to be created in the traditional

Trace log, traceDisable ORACLE trace LoggingAlter system set trace_enabled = falseSelect * from v $ parameter where NAME like '% trace % ';How to disable the oracle listenerr trace log First, go to the listener:LsnrctlView log status:Show

[MongoDB] The connection between two tables, mongodbtables In mongoDB, there are two general way to connect with two tables. Manual Connection and use DBRef1. Basically manual connection Firstly init the data which was saved in the different

MongoDB operation manual CRUD query performance analysis, mongodbcrudThe explain () cursor Method for Analyzing query performance allows you to observe the operations performed by the query system. This method is very useful for analyzing efficient