HP 3000 Manuals

ALLBASE/SQL Performance and Monitoring Guidelines

Lock Impede Screen 

This screen identifies the locks granted to a particular session that are
causing other sessions to wait.


            

To invoke the Lock Impede screen, use the i command from the Lock
subsystem or the /loc i command from other subsystems.

You can also specify the number in response to an SQLMON prompt, for
example:

     SQLMONITOR  OVERVIEW => /loc i 

     PIN: 18381 

When you invoke the screen, you must specify the connection
identification number of a session.  You can specify the connection
identification number on the command line, like this:

     SQLMONITOR  OVERVIEW => /loc i 1 

You can also specify the connection identification number in response to
an SQLMON prompt, for example:

     SQLMONITOR  OVERVIEW => /loc i 
     CID: 1 

The information in the NEW and WAITING fields, which is displayed in
inverse video, applies to the sessions that are waiting for locks.  The
other fields on the screen apply to the session identified by the field
in the upper left corner.

Field Definitions 

REFRESH          The screen refresh rate, in seconds.

CID              The DBEnvironment connection identification number.

PIN              The MPE/iX process identification number of the
                 DBEnvironment session you specified when you invoked
                 this screen.

STATUS           The status of the DBCore call the session has made.
                 This field is equivalent to the STATUS column of the
                 SYSTEM.CALL pseudotable.  The possible values are listed
                 below:

                 Running          DBCore is processing a call from a
                                  session.

                 Waiting for      The session has made a DBCore call, but
                 resource         is waiting until it can acquire a
                                  resource that is currently unavailable.
                                  The resource can be LOCK, LATCH,
                                  BUFFER, THROTTLE, or XACT.

                 Idle             DBCore is not processing a call.

XID              The transaction identifier, equivalent to the XID column
                 of the SYSTEM.TRANSACTION pseudotable.

ISO              The isolation level, equivalent to the ISOLATION LEVEL
                 column of the SYSTEM.TRANSACTION pseudotable.  See the
                 "Concurrency Control through Locks and Isolation Levels"
                 chapter in the ALLBASE/SQL Reference Manual for more
                 information.

USER@ACCT        The MPE/iX user name and account name for the
                 DBEnvironment session.

LABEL            The transaction label, equivalent to the LABEL column of
                 the SYSTEM.TRANSACTION pseudotable.  To assign a label
                 to a transaction, use a BEGIN WORK or a SET TRANSACTION
                 statement.

PRI              The transaction priority, equivalent to the PRIORITY
                 column of the SYSTEM.TRANSACTION pseudotable.  The
                 lowest transaction priority is 255, and the highest is
                 0.

PROGRAM NAME     The name of the program being run.

G                The granularity of the lock, either table (T), page (P),
                 or row (R).

OWNER.TABLE      The name of the table or referential constraint that is
[/CONSTRAINT]    locked.

PAGE/ROW ID      The identifier of the page or row that is locked.  If
                 the lock is a table lock, this field is blank.

GWC              The status of the lock, always set to G to indicate that
                 the lock has been granted to the session indicated by
                 the PID field in the upper left corner of the screen.

MOD              The mode of lock that has been granted, as follows:

                 S    Share
                 X    Exclusive
                 s    Intent share
                 x    Intent exclusive
                 6    Share + intent exclusive
                 R    Recovery exclusive
                 r    Recovery intent exclusive
                 v    Recovery share + intent exclusive

NEW              The lock mode the waiting session is attempting to
                 acquire.  If the lock has been granted, this field is
                 blank.

WAITING          The connection identifier for the DBEnvironment session
                 that is waiting because an incompatible lock has been
                 granted to the session identified by the CID field in
                 the upper left corner of the screen.

Related SET Commands 

Use the SET REFRESH command to modify the refresh rate of the screen.

MPE/iX 5.0 Documentation