Lock Impede Screen [ ALLBASE/SQL Performance and Monitoring Guidelines ] MPE/iX 5.0 Documentation
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.
Click here to view figure.
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
HP 3000 Manuals