What will happen when we put the database in begin backup mode?
alter database begin backup;
When we put the database in begin backup mode header of all datafiles get freez or SCN will not change;during this process it generates excessive redo logs.
Why it will generate excessive redo logs?
suppose you are updating some data in a table and the size of change vector data is 1 KB but the bg process write 8KB of block instead of 1 KB which result in generate excessive redo logs.
Why it is writing 8KB of data?
To avoid block corruption;it will write 8K of data but not I KB.
alter database begin backup;
When we put the database in begin backup mode header of all datafiles get freez or SCN will not change;during this process it generates excessive redo logs.
Why it will generate excessive redo logs?
suppose you are updating some data in a table and the size of change vector data is 1 KB but the bg process write 8KB of block instead of 1 KB which result in generate excessive redo logs.
Why it is writing 8KB of data?
To avoid block corruption;it will write 8K of data but not I KB.
No comments:
Post a Comment