Databases Reference
In-Depth Information
The XIDUSN, XIDSLOT, and XIDSQN values can be used to
identify a transaction, for example when using LogMiner
to query online and archived redo log files.
In step 9 we query the
DBA_WAITERS
dynamic performance view, which is useful to correlate
the blocked transactions to the blocking one, as we can see in the following screenshot:
In the above screenshot observe that session 17 is blocked by session 31, the type of lock,
and IDs of the objects involved.
The
DBA_BLOCKERS
dynamic performance view queried in step 10 is very simple, because
there is only one column returned with the session IDs of the sessions holding locks, in our
example session 31, as shown in the following screenshot:
In step 11 we execute the script
utllockt.sql
, located in the
/rdbms/admin
subfolder
of our
ORACLE_HOME
; this returns a tree representation of the data we have queried in the
dynamic performance views above, merged together. In the next screenshot you can see the
results obtained by the script in this situation:
