Oracle

Below I introduce three kinds of view parallel related content, such as parallelism, parallel execution instance and so on through the experiment. 1, V$pq_tqstat view – Script [Oracle@rac1 ~]$ Cat Showdop.sql Column Server_type format A15

To test the role of database roles, use the set role command to enable roles, setting the default role for database users Create corner R1 and R2, where R2 password authentication, I set the password is Oracle Sql> Conn System/oracle Connected.

1 Preparation work 1.1 Check Initialization parameters Confirm that the gloal_names is true,job_queue_process greater than 0. Perform the following two Sqlplus commands at both the primary and materialized view sites to check that database

/* * Oracle saves the date as an integer offset from a key date in the past (which is January 1, 4712 BC) (that is, save the date as a number); * So you can generate a random date within a specified range by looking for an integer offset that

A First, introduce 2 words Automatic Diagnostic Repository (ADR)- A directory of database diagnostic logs and trace files, called ADR base, corresponding to initialization parameter diagnostic_dest, If you set the ORACLE_BASE environment variable,

Statistics are critical to Oracle databases, especially when using the CBO (cost-based optimizer) pattern, statistics include the use of blocks, free blocks, average length of the table, and statistical information collection time. In the Oracle9i

1. Introduction Sed is a non-interactive editor. It does not modify the file unless you use Shell redirection to save the results. By default, all output lines are printed to the screen. The SED editor processes files (or inputs) line-by-row and

Now the TKPROF program to do further explanation: After the tracing function is turned on, Oracle collects the performance state data of the SQL that is being executed by the tracking session into a trace file. This trace file provides a number of

I/O includes two parts, read and write, to introduce the generation of write operations in Oracle databases first. 2.1. Write Before introducing write operations, simply look at the physical structure of Oracle: Oracle's physical files include the

Oracle Triggers Category: 1. Statement triggers 2, row triggers 3. System Condition Trigger 4. User event triggers 5. INSTEAD of Triggers 1. Statement triggers is a specific statement or a trigger on a statement group that executes on a table

In this method, there are two main ways to achieve the I/O optimization. Oracle uses memory cache to reduce I/O Through some memory cache, such as buffer cache, Log buffer, Sort area, you can reduce the database on I/O requests. When the buffer

Statspack Installation Use and analysis 1. View table Space Select Tablespace_name,file_name from Dba_data_files; 2. Create Statspack table Space Create tablespace perfstat datafile ' d:\oracle\oradata\perfstat.dbf ' size 500m The table space

There are the following questions in the 047 questions 11.View the Exhibit and examine the descriptions of order_items and ORDERS tables. You are want to display the customer_id, product_id, and Total (Unit_price multiplied by QUANTITY) for the

Partition add The new partition can only be added to the end, and if you need to add partitions to the front or center, you need to use partition splitting. ALTER TABLE p95169.order_info Add PARTITION pmax VALUES less THAN (MAXVALUE) tablespace

Oracle server consists of an instance and a database. 1. ORACLE Example The System Global area (SGA) and Background Process are called instances of the database. We use an instance to access the database, a database can only open one instance at a

Data security is a wide range of topics, including network security, operating system security, Application layer Security and database security, Oracle data security is at the database level of security, the following figure is the Oracle security

First, Oracle's dictionary and Dynamic Data dictionary views can basically be divided into three levels. 1.x$ table This section of the table is the basis for the operation of the Oracle database, which is dynamically created by the Oracle

1. Definition Triggers: associated with a table or database event, a trigger defined on a table triggers execution when a trigger event occurs. Trigger Trigger Order 1 execute BEFORE statement level trigger; 2 for each row affected by the

Oracle Partial Recovery method We sometimes need to do a recovery test, however, because the target database is too large, if the full recovery of data files, then need a lot of storage space, but if not to do the recovery test, and how the

Locking guarantees that when a user is updating a row of data in a table, other users cannot update the same row of data at the same time, and they cannot delete or modify the tables that are updated. Locking is divided into two levels: Row level