April 1999
Intermediate to advanced
552 pages
15h 39m
English
Content preview from Oracle Distributed Systems
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DBMS_SNAPSHOT: Managing Snapshots
The DBMS_SNAPSHOT package contains programs that allow you to maintain snapshots and snapshot logs and to set and query package state variables associated with the advanced replication facilities.
How the Package Is Used
The procedures I_AM_A_REFRESH and SET_I_AM_A_REFRESH are used to check and set the package variable REP$WHAT_AM_I.I_AM_A_SNAPSHOT, which numerous replication triggers and procedures reference. The procedures PURGE_LOG and REFRESH are typically run by the DBA and/or scheduled in the job queue.
Installation and Access
The DBMS_SNAPSHOT package is created when the Oracle
database is installed. The
dbmssnap.sqlscript (found in the built-in packages source
directory) contains the source code for this package’s
specification. This script is called by
catproc.sql, which is normally run immediately
after database creation. The script creates the public
synonym DBMS_SNAPSHOT for the package and grants the EXECUTE
privilege on the package to public. All Oracle users can reference
and make use of this package.
DBMS_SNAPSHOT Procedures
Name | Description |
|---|---|
BEGIN_TABLE_REORGANIZATION (Oracle8 only) | Called prior to reorganizing a master table (e.g., through export/import); saves data required to refresh snapshots |
END_TABLE_REORGANIZATION (Oracle8 only) | Called after reorganizing a master table (e.g., through export/import); validates data required to refresh snapshots |
I_AM_A_REFRESH | Returns value of REP$WHAT_AM_I.I_AM_A_SNAPSHOT |
PURGE_LOG | Purges snapshot ... |
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