Oracle snapshot replication

A snapshot of an Oracle database is a table that contains query interceptions on one or more tables or views in a local or remote database. Because snapshots are a subset of a master table, you can use snapshots to speed up database queries. When synchronizing multiple tables in different databases, you can use snapshots to refresh, the database update performance will also be greatly improved.
Due to work and learning needs, the following is a summary of the snapshots created on the test database:
The procedure is as follows:
1. Create snapshot logs
Create snapshot log on full_information;

2. Establish a database chain
Create database link link_tszx
Connect to wll identified by wll using ' Intszx ' ;

Iii. Verification
Select * From full_information @ link_tszx;

4. Create a snapshot:
Create snapshot full_information as select * From full_information @ link_tszx;
5. Create a snapshot and refresh:
alter snapshot full_information refresh fast
Start With sysdate + 1/1440 next sysdate + 1/144;
description:
1. Because snapshot refresh is automatically completed by the server, ensure that the snapshot refresh process is started for the Oracle database. Check whether the snapshot refresh process has been started in the Oracle database. You can view the value of snapshot_refresh_processes in view V _ $ system_parameter as the Database SYS. If it is not 1, the Snapshot refresh process is not started.
2. Start the snapshot refresh process by modifying the initialization file initorcl of the Oracle database. ora, change the value of the snapshot_refresh_processes parameter from 0 to 1, and restart ORACLE data.
3. Note that the Oracle database created a trigger tlog $ _ yh_qfcx Based on yh_qfcx and the snapshot log table mlog $ _ yh_qfcx when creating snapshot logs; when a snapshot is created, the Oracle database creates a table, two views, and one index for us. They are:
one table: Snap $ _ s_yh_policcx;
Two views: mview $ _ s_yh_qfcx and s_yh_qfcx;
one index: I _snap $ _ s_yh_1_cx (
Based on the m_row $ field in the snap $ _ s_yh_1_cx table.

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