Corruption

If you don’t know what procrastination is you could start your own blog. Start a post with something like “I worked with … and decided to write three posts about it”. Procrastination is what you experience before the last post is ready; seemingly simple things take forever to get out the door. This post is important for my own record and shows how to salvage data from a large table with several corrupt blocks. I also had a learning experience I wanted to remember, explaining the redundancy of information here. Previous post was about how to map out tables and the corrupt blocks in a temporary table (that is, not a table created as a global temporary table, but a table you’ll drop when you’re finished.) ...

After you have validated database as shown in previous post any corrupt database blocks will be reported in the view V$DATABASE_BLOCK_CORRUPTION. Now you want to find out the tables that used to have data in these blocks; those data have typically been lost if you have no backup of them or do not posses special tools like DUDE . Before you start I recommend to purge the DBA Recycle Bin if it is in use, as reported here certain queries seem to take longer time when it is not empty. Execute as SYSDBA: ...