Export needs restrict session or not

[farrokhp]

Is it very important to put the database in the " restrict session " mode before start a full database export ?

what's happens if I don't do that ?

[marist89]

Depends on what you are trying to do.

When the database is in restricted session mode, only certain people will be able to connect to the database.

No, with an export, you do not need to be in restricted session. However, if you have users in the system, their changes will still take place. For this reason, some people like to put their database into restricted session so they can get a "clean" export.

[sree_sri]

If the database in open mode and if you take export then their is the chanses to spoil your integrity relation.

When you are taking export your parent table may be not contain the value but your child may contain the value.

I mean If export run on the parent table, The user accessed database at the same time and entered the value in the parent table and he entered the same value in the child table. All ready the value is entered in the parent table, That's why no problem for him. But all ready export took the parent table, Next the export took the child table. So now export have
Un-modified parent table.
Modified Child table.

When you Import these tables data into another database then you will get import errors. Like Unable to find parent key...etc. That's why this is the good practise taking export at restricted mode. Any way wait some more time. Here People are very clever. They can give you some more good information. Even i am waiting ! Good Luck.

[sree_sri]

Martis,

What about of the above scenario? I mean
Un-modified parent table
Modified Child table.

[marist89]

If you are exporting when users are in the database, I recommend using CONSISTENT=Y

[farrokhp]

Does it mean that if I use consistent=Y it is enough to gurantee dump file consistenct but concurrent transactions during export period won't apply to dump file? Is it the case or not ?

[rsuri]

yes, that is the case.
Also when using CONSISTENT=Y you should have a bigger rollback segment available. This is where Export will be getting the consistent data image when users are changing data during the export; otherwise you may get the "snapshot too old..." error.

- Rajeev