Snapshots and SNAPSHOT LOGs
Snapshots are read-only copies of a master table located on a remote node which is periodically refreshed to reflect changes made to the master table.
A snapshot log is a table in the master database that is associated with the master table. ORACLE uses a snapshot log to track the rows that have been updated
- Replication of data in distributed environment. - Using snapshots to replicate data. - Using remote procedure calls.
Snapshot is an object used to dynamically replicate data between distribute database at specified time intervals. In ver 7.0 they are read only.
Simple and Complex.
- A simple snapshot is based on a query that does not contains GROUP BY clauses, CONNECT BY clauses, JOINs, sub-query or snashot of operations.
Time the references to occur when master tables are not in use. Peform the reference the manually immdiately locking the master tables. We can join tables in snopshots by creating
COMPLETE - Tables are completely regenerated using the snapshots query and the master tables every time the snapshot referenced.FAST - If simple snapshot
It is a table that maintains a record of modifications to the master table in a snapshot. It is stored in the same database as master table and is only available
