Oracle X$ View:X$KJBL

The status of buffer locks can be checked through the table X$KJBL; it is not necessary to dump the locks with the ORADEBUG command, in order to get to this information. The table contains the client and shadow locks.    

Column name            Data type            Description
KJBLLOCKP              RAW,kjbl*            Lock pointer. Can be joined with X$LE.LE_KJBL.
KJBLGRANT              VARCHAR2 (9)         Current grant level, valid values are:
                                            KJUSERNL (0), KJUSERCR (1), KJUSERCW (2), KJUSERPR
                                            (3), KJUSERPW (4), KJUSEREX (5)
KJBLREQUEST            VARCHAR2 (9)         Request Level, valid values are:
                                            (See KJBLGRANT)
                                            KJBLROLE NUMBER Granted Role:
                                            KJBL_GRANT_N (0x00), KJBL_GRANT_S (0x01)
                                            KJBL_GRANT_X (0x02), KJBL_REQ_S (0x04),
                                            KJBL_REQ_X (0x08), KJBL_REQ_STL (0x10),
                                            KJBL_REQ_CR (0x10), KJBL_OACK (0x20),
                                            KJBL_ROLE_G (0x40), KJBL_HAS_PI (0x80)
                                            
KJBLRESP               RAW, kjbr*          Current Resource Info (Resource pointer)
KJBLNAME               VARCHAR2 (30)       Resource name in Hex notation ([id1], [id2], [Type])
KJBLNAME2              VARCHAR2 (30)       Resource name in Decimal notation (id1, id2, Type)
KJBLQUEUE              NUMBER              Grant / Convert queue:
                                           Grant Queue (0x00), Convert Queue 0x80
KJBLLOCKST             VARCHAR2 (64)       Lock state:
                                           KJUSERGRANTED (0x00), KJUSEROPENING (0x01),
                                           KJUSERCLOSING (0x02), KJUSERCANCELLING (0x04),
                                           KJUSERCVTING (0x08), KJUSERSTANDALONE (0x10),
                                           KJUSERASTDELAYED (0x20), KJUSERMSGPENDING(0x40),
                                           KJUSERFROZEN (0x80)
KJBLWRITING            NUMBER              Writing
                                           ·0, not writing; 1, writing
KJBLREQWRITE                               Write requested
                                           ·  0, no request; 1, write requested
KJBLOWNER              NUMBER              Owning instance – node id
KJBLMASTER             NUMBER              Master instance – node id
KJBLBLOCKED            NUMBER              Blocked lock? – Checks if there is a converting lock
KJBLBLOCKER            NUMBER              Blocking lock? - Checks if there is a lock held in an incompatible mode

    The columns KJBLBLOCKER and KJBLBLOCKED in particular let you determine if you are waiting on blocked lock or if you are blocking other sessions. With this table, it is also possible to determine where the lock is mastered and the role of the lock.