Oracle

Google maps are queried based on Oracle. How does Google store maps in Oracle? Here we use the dbms_lob package to briefly understand the process.   1) create a t table: 00:32:04 HR @ orcl (^ ω ^) Create Table T (A varchar2 (20), B BLOB);

Table It is a segment, but the segment is not necessarily a table, and the segment also has the index segment, undo segment, partition and so on.The details are as follows:First, we need to understand their concept: tables are logical objects;

  The backup and recovery capabilities are "broken. The principle is briefly introduced here:   Oracle records the changes of all data files in the form of logs. Therefore, as long as all ORACLE data files are backed up in a certain period of

Many of Oracle's experience is not from the industrial environment, many problems and experience can be accumulated from their own tests.Experiment to be done, but also to think!What is the starting point of thinking?Which of the following is my

Dbms_fga can be used to audit select statements of a specified table from Oracle9i.However, the SELECT statement can only be audited in 9i, And the DML audit function can be implemented in 10 Gb.Dbms_fga is used to demonstrate the audit function of

(I) Requirements To facilitate communications between nodes in the RAC environment, ssh equivalence is often required. In short: The user or program does not need to enter a password when connecting from one machine to another. The background of

(I) index skip Scan WhenThe table has a composite index. In the query, other columns except the first column in the index are used as conditions, and the optimizer mode is CBO. In this case, the query plan may use the SS Skip Scan detects the

Environment: sys@ORCL> select * from v$version;BANNER----------------------------------------------------------------Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - ProdPL/SQL Release 10.2.0.1.0 - ProductionCORE 10.2.0.1.0

Its definition: Indicates the order of rows in the table based on the index value, and notifies CBO about table row and index synchronization. ● This value is similar to the number of blocks, indicating that the same data is stored in a centralized

Environment: sys@ORCL> select * from v$version where rownum=1;BANNER----------------------------------------------------------------Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Prodsys@ORCL> !uname -aLinux localhost.localdomain 2.6.18-

The wave of big data is surging, and a new information technology revolution is about to begin. "Spring River plumbing duck Xianzhi", as a database practitioner, is particularly profound to me. However, whether it is Oracle's exadata, MySQL's scale

InProduction environment, we will find: ① The index tablespace I/O is very high② The "DB file sequential read" Wait event is also relatively highThis shows that the entire database system and indexes have many read/write operations and have become

Performance Tuning is a task that every DBA can encounter in his career. From the world's top five hundred core systems to the purchase and sale of township enterprises, there is almost always a time to optimize In the face of all kinds of systems,

1 Prepare the test environment:SQL> Create Table C as select * from Dept; Table created. SQL> select * from C; Deptno dname Loc-------------------------------------10 Accounting New York20 research Dallas30 sales Chicago40 operations Boston SQL>

This index topic has not seen the sun for a long time, I think it is special, unhappy, so I have this article It is rumored that B * tree indexes are often used in the application development stage as "cannon fodder", while in the maintenance

InOne frequency Commit/rollbackOr disk I/O problems, a large number of physical read/write contention So we will often see Log File sync wait events appear in top events The metrics for evaluating Log File sync wait events are the average wait time

Backup definition.The fundamental purpose of backup is to restore. If needed, it can be recovered, that is, backup. For example, archive log file is a backup of online redo log file. The validity of the backup.Eygle said on its blog: "The system

Environment: 14:56:24 sys@ORCL (^ω^) select * from v$version where rownum=1;BANNER--------------------------------------------------------------------------------Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Prod Oracle Net covers

The solution is as follows: SQL> Conn/As sysdbaConnected.SQL> conn HR/hrError:ORA-01033: Oracle is initializing or shutting downWarning: you are no longer connected to Oracle.SQL> shutdown immediateORA-01109: the database is not openThe database has

Background: Now, I want to practice Incremental backup of RMAN. The original test database is in non-archive mode. So after calling and shutdown an instance, the open instance fails to get started. sys@ORACLE10> alter database open;alter database