FROM_VAL

VARCHAR2(4)

PCM lock initial state: NULL; S; X; SSX

TO_VAL

VARCHAR2(4)

PCM lock initial state: NULL; S; X; SSX

ACTION_VAL

VARCHAR2(51)

Description of lock conversions:

• Lock buffers for read
• Lock buffers for write
• Make buffers CR (no write)
• Upgrade read lock to write
• Make buffers CR (write dirty buffers)
• Downgrade write lock to read (write dirty buffers)
• Write transaction table/undo blocks
• Transaction table/undo blocks (write dirty buffers)
• Make transaction table/undo blocks available share
• Rearm transaction table write mechanism

COUNTER

NUMBER

Number of times the lock operation executed