MOS Note:136697.1 – New HCHECK.SQL for Oracle Database 12c

A while back we added this slide to our big slide deck:

The story behind this slide

A large and important customer in the US tested a patch set upgrade – but when they approached the production upgrade from 11.2.0.2 to 11.2.0.3 on a large RAC cluster they’ve had to cancel the attempt and revert to the previous state.

Reason

They’ve hit a dictionary corruption somewhere silently sleeping in the database causing no trouble at all so far – until the upgrade touched the broken structures

They’ve asked us:
“How could we ensure the database is really healthy and in good state?”

And unfortunately there’s no 100% confirmation as there may be an unknown issue we are not aware of. But we can test two things:

  • Let RMAN verify the logical integrity of the Oracle blocks
  • Let the hcheck.sql script provided by Oracle Support check and test for known dictionary issues

It’s actually a general recommendation we give to customers for a long time to check their really important and business critical databases from time to time during off-peak hours.

Recently Oracle Support updated hcheck.sql to version 4 to include Oracle Database 12c checks as well. Unfortunately the script doesn’t get updated very often. Expect a max of 2 updates per year.

Please find it here:

–Mike

Leave a Reply

Your email address will not be published. Required fields are marked *