Comments on: Oracle: What is an Unrecoverable Data File?

By: Tom

Tom — Thu, 17 Jun 2010 14:50:36 +0000

Insert Append operations are logged unless you use the nologging clause. If you use force logging it will happen anyways.

Here is the testcase that was tried.

Archive log mode
Take hot backup
insert records into a table with the append hint
shutdown the DB
delete the tablespace
mount the DB
restore the tablespace
recover it
open the db
query the table to validate the records that were added after the backup by the insert append hint are there.

If you use the no logging option then it won’t be logged.

Here is a link to asktom on this very same question.

http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:8289905224297

By: Blogroll Report 29/01/2009 – 05/02/2010 « Coskan’s Approach to Oracle

Blogroll Report 29/01/2009 – 05/02/2010 « Coskan’s Approach to Oracle — Fri, 05 Mar 2010 10:00:05 +0000

[...] on Solaris 17-How to report if there was an unrecoverable operation happened? Catherine Chow-Oracle: What is an Unrecoverable Data File? 18-How to use latch classes in case you really want to change the spin count and cause minimal [...]

By: Catherine Chow

Catherine Chow — Wed, 03 Mar 2010 17:58:39 +0000

Thanks for your comment and the simplified query. You are correct, unrecoverable objects can also be indexes, and this should also be identified. Please note, unrecoverable indexes will only become an issue if they cannot be reconstructed by the underlying tables. Cheers…

By: coskan

coskan — Sun, 28 Feb 2010 16:41:49 +0000

Nice one Catherine,

For the second query (unrecoverable objects) . you assume that it is a table (join to dba_tables) you wrote the query but it might as well be an index and also some of the unnecessary joins can be avoided by using v$segment_statistics instead of v$segstats.

select distinct ss.owner,ss.object_name, ss.object_type
,ss.tablespace_name, ts.logging tablespace_level_logging
from
v$segment_statistics ss, dba_tablespaces ts,v$datafile df
where
ss.statistic_name =’physical writes direct’
and ss.value >0
and df.unrecoverable_change# >0
and ss.ts#=df.ts#
and ss.tablespace_name=ts.tablespace_name;