undo transaction sql

Reprinted from: http://blog.csdn.net/leshami/article/details/5731158One, rollback (ROLLBACK) and undo (undo)Rollback and roll forward are important means of ensuring that the data in an Oracle database is in a consistent state. --Before the 9i

The database usually implements the transaction with the help of log, the common have undo log, redo Log,undo/redo log all can guarantee the transaction characteristic, Undolog implements the transaction atomicity, Redolog realizes the transaction

  Fault: The undo tablespace is getting bigger and bigger, so the final data crashes due to insufficient disk space; Problem analysis: the cause of the problem is as follows:1. There is a large volume of transactions that allow Oracle undo to

Symptom: Undo table space is getting bigger and longer this end data crashes because of insufficient disk space;Problem Analysis: The causes of the problem are mainly the following two points:1. There is a large volume of transactions so that Oracle

Monitor and manage the use of Oracle UNDO tablespace The monitoring and management of Oracle Database UNDO tablespaces is one of our most important tasks in daily life. The UNDO tablespaces are usually managed automatically by Oracle (determined by

Originally intended to write about the transaction control process in the SSIS package, it was found that many of the basic concepts needed to be based on the isolation level of SQL Server transactions and transactions. So it took some time to get a

Read consistency analysis: undo, read consistency: undoThe following uses the consistent read Analysis of undo:[Oracle @ localhost ~] $ Lsb_release-LSB Version: core-3.1-ia32: core-3.1-noarch: graphics-3.1-ia32: graphics-3.1-noarchDistributor ID:

The role of undoUse the undo tablespace to hold the front image of a block of data read from a data file, providing the information required for the following 4 scenarios:1. Rolling back things: Rollback2. Read consistency: When a long query is

Oracle Database ORA-01555 snapshots are old (undo tablespace: UNDO tablespace) UNDO tablespaces are used to store UNDO data, oracle writes the old data of these operations to the undo segment when performing DML operations, to ensure rollback or

First, back paragraph introduction In an Oracle database, when something modifies the data, Oracle first saves the original value of the data to a fallback segment. A thing can only save its fallback information to a fallback segment, while multiple