Question: I need to know how I can
count the number of connections to my Oracle database.
I need the connection count from Linux/UNIX. Also, how
can I monitor the number of connection sessions within
Oracle?
Answer: There are two says to
monitor Oracle connections, within Oracle and outside of
Oracle with the "ps" command. Oracle provides the
v$process and v$session views within Oracle to
get detailed information about Oracle connected sessions.
You can also see the UNIX process IDs for all executing
processes on your database server if you are not using the
multi-threaded server (shared servers).
The following script is extremely
useful for showing all dedicated connections to Oracle.
Please note that this script displays the UNIX process ID
(PID) and also gives information about the executing
program. It is also possible to enhance this script to show
the actual SQL statement by joining into the v$sql
view.
--**************************************************************
-- session.sql
-- count and monitor the number of
connected Oracle sessions
rem session.sql -
displays all connected sessions
set echo off;
set
termout on;
set linesize 80;
set pagesize 60;
set newpage 0;
select
rpad(c.name||':',11)||rpad('
current logons='||
(to_number(b.sessions_current)),20)||'cumulative
logons='||
rpad(substr(a.value,1,10),10)||'highwater
mark='||
b.sessions_highwater Information
from
v$sysstat a,
v$license b,
v$database c
see code depot for full scripts
where
a.name
= 'logons cumulative'
;
ttitle "dbname
Database|UNIX/Oracle Sessions";
set heading off;
select 'Sessions on database '||substr(name,1,8) from
v$database;
set heading on;
select
substr(a.spid,1,9)
pid,
substr(b.sid,1,5) sid,
substr(b.serial#,1,5)
ser#,
substr(b.machine,1,6) box,
substr(b.username,1,10)
username,
substr(b.osuser,1,8) os_user,
substr(b.program,1,30)
program
from
v$session b,
v$process a
where
b.paddr = a.addr
and
type='USER'
order by
spid
;
ttitle off;
set
heading off;
select 'To kill, enter SQLPLUS> ALTER
SYSTEM KILL SESSION',
''''||'SID, SER#'||''''||';'
from dual;
spool off;
Here is a sample listing from running
this script. Please note that it begins by displaying
summaries of all current, cumulative, and the high-water
mark for logons before displaying the details for each
session:
SQL>
@session
INFORMATION
----------------------------------------------------------------------------
PRODLIVE: current logons=14 cumulative logons=166
highwater mark=14
UNIX/Oracle Sessions
Sessions on database PEMINE
Sat Oct 13 page 1
dbname Database
UNIX/Oracle Sessions
PID SID
SER# BOX USERNAME OS_USER PROGRAM
--------- -----
----- ------ ---------- --------
---------------------------
1005 14 124 hawk CASH
rhayes runmenu50@hawk
1139 13 39 hawk STAFF clarson
runmenu50@hawk
1526 11 1550 hawk BURLESON burleson
sqlplus@hawk
1690 15 47 hawk CASH kjoslin
runmenu50@hawk
2482 16 263 hawk STAFF brobinso
runmenu50@hawk
2568 17 26 BELLEV SCHED Bellmont
F45RUN32.EXE
27180 9 228 hawk PATIENT daemon
sqlplus@hawk
29316 8 3238 hawk CASH jdutcher
runmenu50@hawk
29440 12 137 hawk CASH lchapman
runmenu50@hawk
3231 18 173 hawk STAFF jhahn
runmenu50@hawk
3241 19 39 BELLEV SCHED dplueger
F45RUN32.EXE
273 20 11 BELLEV SCHED dplueger
R25SRV32.EXE
To kill, enter SQLPLUS> ALTER SYSTEM
KILL SESSION 'SID, SER#';
SQL>
If you want to move outside of Oracle
and monitor connections for the session at the UNIX level,
you must correlate the Oracle PID with the UNIX PID. To see
details of these processes, you can write an Oracle script
to filter the UNIX ps output to only include these
processes:
ps_pid.ksh
#/bin/ksh
sqlplus cpi/oracle@prodlive<<!
set pages
999
set feedback off
set echo off
set heading
off
spool /tmp/run_pid.ksh
select
'ps -ef|grep
'||spid||'grep –v grep'
from
v\$process
see code depot for full scripts
where
spid is
not NULL
;
spool off;
!
# Execute
the UNIX commands . . . .
chmod +x /tmp/*.ksh
/tmp/run_pid.ksh
Here is the output from this script. As you
see, the SQL*Plus script builds the UNIX ps command
for the Oracle PIDs and then executes the command:
root>
/tmp/run_pid.ksh
jjahn 3231 3129 0 08:12:17 - 0:00 oraclePA
bbeckero 2482 2377 0 07:59:26 - 0:00
oraclePA
scarf 2376 785 0 07:59:03 ttyp9 0:00
telnetd
brobins 2377 2376 0 07:59:04 ttyp9 0:01
runmenu50 pamenu
monte 1372 1 0 Sep 21 - 5:58 /opt/hpnp/bin/hpnpd
jmels 1886 1878 0 Sep 21 ttyp1 0:00 tee -a
This script allows you to see the start time
for the UNIX connection and also see the cumulative CPU
consumption for each task. This is a great script for
monitoring Oracle connections over time. Also
see the
code
depot for a full set of Oracle
session counting and monitoring scripts.
