전체 글 (661) 썸네일형 리스트형 107 - [Oracle 19C] How to use SQL*Loader # we will learn the sql loader # SQL*Loader is a bulk loader utility used for moving data from external files into the Oracle database # move the file emp.csv to server /u01/app/oracle show user show con_name /* USER is "HR" CON_NAME ------------------------------ ORCLPDB */ CREATE TABLE EMP_LOAD (EMPNO NUMBER , FNAME VARCHAR2(100), LNAME VARCHAR2(100) ); /* Table EMP_LOAD created. */ SELECT * F.. 106 - [Oracle 19C] Automatic Tuning of Undo Retention, example Automatic Tuning of Undo Retention Oracle Database automatically tunes the undo retention period based on how the undo tablespace is configured. If the undo tablespace is configured with the AUTOEXTEND option, the database dynamically tunes the undo retention period to be somewhat longer than the longest-running active query on the system. However, this retention period may be insufficient to ac.. 105 - [Oracle 19C] Flashback table and Flashback Version Query show user show con_name /* USER is "HR" CON_NAME ------------------------------ ORCLPDB */ select * from employees; /* EMPLOYEE_ID FIRST_NAME LAST_NAME EMAIL ----------- -------------------- ------------------------- -------------- 198 Donald OConnell DOCONNEL 199 Douglas Grant DGRANT 200 Jennifer Whalen JWHALEN 201 Michael Hartstein MHARTSTE 202 Pat Fay PFAY 203 Susan Mavris SMAVRIS 204 Hermann.. 104 - [Oracle 19C] Categories of Undo Active Uncommitted undo information required if a user wants to roll back or if the transaction has failed. Uncommitted undo information is never overwritten. Unexpired Committed undo information Old undo information with an age that is less than the current undo retention period retained for consistent read and Oracle Flashback operations Expired Expired undo information Old (committed) undo in.. 103 - [Oracle 19C] About the Undo Retention Period Managing UNDO Data About the Undo Retention Period UNDO_RETENTION The default is 900s Which is 15m The user A should see the data as 10:00 exactly And this is called read consistency User B - This will not reflect the user A query, User A still see the old data, because he execute the query at 10:00 am 102 - [Oracle 19C] Overview of Automatic Undo Management Managing UNDO Data Overview of Automatic Undo Management Oracle provides a fully automated mechanism for managing undo information and space. the database manages undo segments in an undo tablespace Automatic undo management is the default mode for a newly installed database. An auto extending undo tablespace named UNDOTBS1 is automatically created when you create the database with Databas.. 101 - [Oracle 19C] Local Undo Mode vs Shared Undo Mode Managing UNDO Data Local Undo Mode Versus Shared Undo Mode "LOCAL_UNDO_ENABLED= true" - This mean each pluggable can have its own undo There is only one shared UNDO tablespace(in CDB root). There can be a local UNDO tablespacein each PDB You can set a CDB in local UNDO mode either at CDB creation or by altering the CDB property. table :DATABASE_PROPERTIESproperty LOCAL_UNDO_ENABLED= true note.. 100 - [Oracle 19C] Comparing Undo Data and Redo Data Managing UNDO Data Comparing Undo Data and Redo Data Redo log files stores changes to the database as they occur and are used for data recovery. UNDO Redo Used for Rollback, read consistency, flashback Rolling forward of database changes Stored in Undo segments Redo Log Files Example show user; show CON_NAME; /* USER is "PDB10_ADMIN" CON_NAME ------------------------------ PDB10 */ select TABLES.. 이전 1 ··· 15 16 17 18 19 20 21 ··· 83 다음
