EVENT:10211 check index block integrity

Event:10211                  See <Note:32969.1> for similar events / parameters
~~~~~~~~~~~                    

Version/Use:
  7.0 - 8.1.7  Check data block integrity after each modification
  9.0+         This event is no longer valid. Use <Parameter:DB_BLOCK_CHECKING>
                instead.

7.0 - 8.1.7 "Check data block integrity after each modification"
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  NOTE: Events should NEVER be set by customers unless advised to do so by
        Oracle Support Services. Read <Note:75713.1> before setting any event.

Summary Syntax:
  This event should be set at instance level:
    EVENT="10211 trace name context forever, level 10"

Levels:
  This event is either ON (level 1 or higher) or OFF (not set)

  Note that in 8.1.6 onwards you should use the <Parameter:DB_BLOCK_CHECKING>
  instead of this event.

Description/Steps:
  Event:10211 enables index block integrity checking.
  The causes the index layer to perform a number of checks on the contents
  of a index block. If the block is found to be corrupt in some way it is
  marked as SOFTWARE CORRUPT.

  NB: Blocks are ONLY checked/corrupted when CHANGED. They are NOT checked
      when accessed for read.                                   

  Take care with this as if there are blocks in the database which
  are being accessed happily but have a minor corruption this will
  mark the block as corrupt.

  Once a block in an index is marked SOFTWARE CORRUPT it is best to
  rebuild the entire index.

*** WARNING:
        Releases with <Bug:792610> are best to keep this event disabled
        as an index corruption can lead to rollback segment corruption
        which is written to the redo stream.

  See <Note:32969.1> for more detail of various block checking features.

Example Output / Interpreting Output:
  This event will cause an ORA-600 error to be signalled if a corruption
  is detected after a data block has been modified. The exact content
  of the trace file depends on the ORA-600 and the action at the time
  of the corruption being noticed. Refer to the relevant ORA-600 article
  for the error which is signalled.

Related:
  Database block checking features                          <Note:32969.1>
  Table and Cluster block equivalents          <Event:10210> <Event:10212>