RE: DBMS_JOB scheduling

From: Igor Neyman <ineyman_at_perceptron.com>
Date: Wed, 23 Jul 2003 09:41:33 -0400
Message-Id: <25998.339116@fatcity.com>

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Raj,

You must be speaking from "UNIX heights" -:-)

Under Windows I find dbms_job much more reliable than windows "at" scheduling.

Actually, never had problems with dbms_job "forgetting" to run a job.

Igor Neyman, OCP DBA

ineyman_at_perceptron.com

-----Original Message-----
From: ml-errors_at_fatcity.com [mailto:ml-errors_at_fatcity.com] On Behalf Of Jamadagni, Rajendra
Sent: Wednesday, July 23, 2003 9:24 AM
To: Multiple recipients of list ORACLE-L Subject: RE: DBMS_JOB scheduling

Garry,

have you tried select to_char(sysdate,'D') from dual ??

This is really nice, but my only gripe with dbms-job is that is isn't reliable ... it wasn't in 9ir1 on aix and we didn't even look at it in 9ir2. in 9ir1 dbms_job used to _forget_ to run jobs after some time and the workaround was like setting job_processes to a very large number.

nevertheless, I think what you have attempted is fantastic and worthy of adoption ...

Raj

Rajendra dot Jamadagni at nospamespn dot com All Views expressed in this email are strictly personal. QOTD: Any clod can have facts, having an opinion is an art !

-----Original Message-----
From: Garry Gillies [mailto:g.gillies_at_weir.co.uk] Sent: Wednesday, July 23, 2003 5:59 AM
To: Multiple recipients of list ORACLE-L Subject: DBMS_JOB scheduling

Any Interest?

The DBMS_JOB package is supplied by Oracle to allow the running of procedures at regular intervals. Unfortunately the INTERVAL parameter is limited to 128

characters, which prevents you from getting very complex (user defined functions [in the interval parameter] do not work well - according to Fuerstein in his book Oracle Built In Packages).

The situation is eased somewhat by the fact that the NEXT_DATE parameter can be supplied to the procedure as an in/out parameter - and the procedure can contain whatever code is necessary to calculate when next to run. This is all very well, but custom coding scheduling routines can quickly become tedious.

On the basis of "do it once and get it over with" I have written a function called NEXT_DATE which I have wrapped in a package called CRON.

There is a Unix program called cron which runs jobs on a regular basis. Although the scheduling data supplied to cron is simple and concise, complex schedules are easy to specify.

The NEXT_DATE function takes in a cron schedule string and returns the next date that conforms to the schedule - or you can supply a cron schedule and a date

and it will return the first date after the supplied date that conforms to the schedule. At the moment it is not very friendly on the error detection front. A VALUE_ERROR is returned if it deems the cron schedule to be invalid. You will also get a VALUE_ERROR if the next valid date is more than twenty seven years in the future. DBMS_OUTPUT is used to display error messages which will hopefully give you a clue.

This will be improved if I receive enough complaints ( and suggestions for improvements).

THE CRON SCHEDULE A cron schedule consists of five components, each separated from the next by a space.
The syntax is identical for all components. The components represent

         Minute in Hour 
         Hour in day 
         Day in month 
         Month in year 
         Day of Week - A bit of a bugger this one. 
         In Unix land the day numbering runs from 0-6 with 0 being

Sunday. In Oracle the day numbering depends on the setting of NLS_TERRITORY. I have chosen to go with ISO standard 8601:1998 which runs from 1-7 with 1 being Monday. This is so close to the Unix convention that I can interpret Unix cron schedules correctly.

Curiously, Oracle do not provide a date format which supplies this number. The ISO week number is available with the format 'IW', but not the ISO day number. If you have a field of type date called dt, you can obtain the ISO day number with ( trunc(dt) - trunc(dt ,'IW') ) + 1

A component can consist of an asterisk * which represents all valid values or a number of elements separated by a comma (if only one element is

supplied, forget the comma). An element can be a single number - valid for the component (32 in "Day in month" is invalid) or two numbers separated by a hyphen - which represents a range.

EXAMPLES Run every hour on the hour

0 * * * *
Run twice every hour, on the hour and on the half hour

0,30 * * * *
Run twice every hour, on the hour and on the half hour between 08:00 and

16:59

0,30 8-16 * * *
Run twice every hour, on the hour and on the half hour between 08:00 and

16:59, Monday to Friday

0,30 8-16 * * 1-5
Run at 11:12 every Friday the 13th

11 12 13 * 5
Run at 04:00 every leap year on february 29

0 4 29 2 *
Run at 04:00 every leap year on february 29 when february 29 is a Thursday

0 4 29 2 4

Garry Gillies
Database Administrator
Business Systems
Weir Pumps Ltd
149 Newlands Road, Cathcart, Glasgow, G44 4EX

T: +44 0141 308 3982 
F: +44 0141 633 1147 
E: g.gillies_at_weirpumps.com

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<div class=3DSection1>

Raj,

You must be speaking from = “UNIX
heights” -J</fon= t>

Under Windows I find dbms_job much = more
reliable than windows “at” scheduling.

Actually, never had problems with = dbms_job
“forgetting” to run a job.

<div>

Igor Neyman, OCP = DBA

ineyman_at_perceptron.com</font= >

</div>

-----Original = Message----- 
From: =
ml-errors_at_fatcity.com
[mailto:ml-errors_at_fatcity.com] On = Behalf Of Jamadagni,
Rajendra 
Sent: Wednesday, July 23, =
2003
9:24 AM 
To: Multiple recipients =
of list
ORACLE-L 
Subject: RE: DBMS_JOB =
scheduling

Garry,

1. have you tried select to_char(sysdate,'D') = from
dual ??

This is really nice, but my only gripe with = dbms-job
is that is isn't reliable ... it wasn't in 9ir1 on aix and we didn't = even look
at it in 9ir2. in 9ir1 dbms_job used to _forget_ to run jobs after some = time
and the workaround was like setting job_processes to a very large = number.

nevertheless, I think what you have attempted = is fantastic
and worthy of adoption ...

Raj 
<span =

style=3D'font-size:10.0pt'>----------------------------------------------=
----------------------------------</span></font>

 
Rajendra dot Jamadagni =
at
nospamespn dot com 
All Views expressed in =
this email
are strictly personal. 
QOTD: Any clod can have =
facts, having
an opinion is an art !

-----Original Message----- 
From: Garry Gillies [<a
href=3D"mailto:g.gillies_at_weir.co.uk">mailto:g.gillies_at_weir.co.uk</a>]</sp= an>
 
Sent: Wednesday, July =
23, 2003 5:59
AM 
To: Multiple recipients =
of list
ORACLE-L 
Subject: DBMS_JOB =
scheduling


Any Interest?

The DBMS_JOB package is supplied by Oracle to = allow
the running of procedures at regular intervals. Unfortunately the = INTERVAL
parameter is limited to 128

characters, which prevents you from getting = very complex
(user defined functions [in the interval parameter] do not work well - according to Fuerstein in his book Oracle Built In = Packages).

The situation is eased somewhat by the fact = that the
NEXT_DATE parameter can be supplied to the procedure as an in/out = parameter -
and the procedure can contain whatever code is necessary to calculate = when next
to run. This is all very well, but custom coding scheduling routines can quickly become tedious.

On the basis of  "do it once and = get it over
with" I have written a function called NEXT_DATE which I have = wrapped in a
package called CRON.

There is a Unix program called cron which = runs jobs on
a regular basis. Although the scheduling data supplied to cron is simple = and
concise,  complex schedules are easy to specify.

The NEXT_DATE function takes in a cron = schedule string
and returns the next date that conforms to the schedule - or you can = supply a
cron schedule and a date

and it will return the first date after the = supplied
date that conforms to the schedule. At the moment it is not very = friendly on
the error detection front. A  VALUE_ERROR is returned if it deems = the cron
schedule to be invalid. You will also get a  VALUE_ERROR if the = next valid
date is more than twenty seven years in the future. DBMS_OUTPUT is used = to
display error messages which will hopefully give  you a clue. =


This will be improved if I receive enough = complaints (
and suggestions for  improvements).

THE CRON SCHEDULE

A cron schedule consists of five components, = each
separated from the next by a space. 
The syntax is identical =
for all
components. 
The components =
represent
 
       &nbs= p;
Minute in Hour 
       &nbs= p;
Hour in day 
       &nbs= p;
Day in month 
       &nbs= p;
Month in year 
       &nbs= p;
Day of Week - A bit of a bugger this one. 
       &nbs= p;
In Unix land the day numbering runs from 0-6 with 0 being Sunday. In = Oracle the
day numbering depends on the setting of NLS_TERRITORY.

       &nbs= p; I
have chosen to go with ISO standard  8601:1998 which runs from 1-7 = with 1
being Monday. This is so close to the Unix convention that I can = interpret Unix
cron schedules correctly.

       &nbs= p;
Curiously, Oracle do not provide a date format which supplies this = number. The
ISO week number is available with the format 'IW', but not the ISO day = number.
If you have a field of type date called dt, you can obtain the ISO day = number
with ( trunc(dt) - trunc(dt ,'IW') ) + 1

A component can consist of an = asterisk  
*    which represents all valid values or a number of = elements
separated by a comma (if only one element is

supplied, forget the comma). An element can = be a
single number - valid for the component (32 in "Day in month" = is
invalid) or two numbers separated by a hyphen   -   = which
represents a range.

EXAMPLES

Run every hour on the hour 
     =
0 * * * *
 
Run twice every hour, on =
the hour
and on the half hour 
     =
0,30 * * *
* 
Run twice every hour, on =
the hour
and on the half hour between 08:00 and 
16:59 
     =
0,30 8-16
* * * 
Run twice every hour, on =
the hour
and on the half hour between 08:00 and 
16:59, Monday to =
Friday
 
    0,30 =
8-16 * * 1-5
 
Run at 11:12 every =
Friday the 13th
 
    11 12 =
13 * 5
 
Run at 04:00 every leap =
year on
february 29 
    0 4 =
29 2 *
 
Run at 04:00 every leap =
year on
february 29 when february 29 is a Thursday 
    0 4 =
29 2 4


Garry Gillies 
Database =
Administrator
 
Business =
Received on Wed Jul 23 2003 - 08:41:33 CDT