RE: Does primary key structure impact UPDATE performance?

  • From: "Khedr, Waleed" <Waleed.Khedr@xxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>
  • Date: Mon, 17 May 2004 10:04:28 -0400

I meant if the columns you are updating are part of any indexes =
(including the PK)?

Regards,

Waleed

-----Original Message-----
From: Thomas Jeff [mailto:jeff.thomas@xxxxxxxxxxx]
Sent: Monday, May 17, 2004 9:56 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: RE: Does primary key structure impact UPDATE performance?


Nope, no extra indexes other then the PK columns.

Question:  Looking at one of the bind variable values which maps to=3D20
a date:  value=3D3D"1/1/1899 0:0:0"

0:0:0 is not a valid time.   How would this statement succeed then?


-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Khedr, Waleed
Sent: Monday, May 17, 2004 8:36 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: RE: Does primary key structure impact UPDATE performance?


Are the updated columns indexed?

Waleed

-----Original Message-----
From: Thomas Jeff [mailto:jeff.thomas@xxxxxxxxxxx]
Sent: Monday, May 17, 2004 9:29 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: RE: Does primary key structure impact UPDATE performance?


Thanks Jonathan.   However, the datatypes are correct, i.e. dty=3D3D3D12 =
=3D
=3D3D
date,
and dty=3D3D3D1
varchar2 for the subsequent columns:
 WHERE SRC_EFF_FROM_DT =3D3D3D :66 AND KEY_ID =3D3D3D :67 AND SOURCE_ID =
=3D
=3D3D3D :68


 bind 65: dty=3D3D3D12 mxl=3D3D3D07(07) mal=3D3D3D00 scl=3D3D3D00 =
pre=3D3D3D00 =3D
oacflg=3D3D3D03 =3D3D
oacfl2=3D3D3D0 size=3D3D3D0 offset=3D3D3D8
   bfp=3D3D3D11036b238 bln=3D3D3D07 avl=3D3D3D07 flg=3D3D3D01
   value=3D3D3D"1/1/1899 0:0:0"
 bind 66: dty=3D3D3D1 mxl=3D3D3D128(80) mal=3D3D3D00 scl=3D3D3D00 =
pre=3D3D3D00 =3D
oacflg=3D3D3D03 =3D3D
oacfl2=3D3D3D10 size=3D3D3D0 offset=3D3D3D16
   bfp=3D3D3D11036b240 bln=3D3D3D128 avl=3D3D3D28 flg=3D3D3D01
   value=3D3D3D"0004021396~0004021396~RG~500"
 bind 67: dty=3D3D3D1 mxl=3D3D3D32(30) mal=3D3D3D00 scl=3D3D3D00 =
pre=3D3D3D00 =3D
oacflg=3D3D3D03 =3D3D
oacfl2=3D3D3D10 size=3D3D3D0 offset=3D3D3D144
   bfp=3D3D3D11036b2c0 bln=3D3D3D32 avl=3D3D3D05 flg=3D3D3D01
   value=3D3D3D"SAPR3"                                 =3D3D20



Waleed:  No chaining.   Thought of that early on.





-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx
<mailto:oracle-l-bounce@xxxxxxxxxxxxx> ] On Behalf Of Jonathan Lewis
Sent: Monday, May 17, 2004 7:57 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: Re: Does primary key structure impact UPDATE performance?




Judging by the number of table blocks you read
to update a single row, it looks as if your index
is not engineered to meet the needs of the update,
and is currently doing something along the lines of:
    check 250,000 rows in the index leaf blocks,
    and eliminate 249,950 of them, then check 50
    rows against the table to find the right one.

If you think the code looks as if it is supplying
all the columns of the index, check the types of
the incoming bind variables to make sure they
match the types of the columns.  You may be
losing index precision because of a coercion
problem.


Regards

Jonathan Lewis

http://www.jlcomp.demon.co.uk <http://www.jlcomp.demon.co.uk>=3D3D20

http://www.jlcomp.demon.co.uk/faq/ind_faq.html
<http://www.jlcomp.demon.co.uk/faq/ind_faq.html>=3D3D20
The Co-operative Oracle Users' FAQ

http://www.jlcomp.demon.co.uk/seminar.html
<http://www.jlcomp.demon.co.uk/seminar.html>=3D3D20
Optimising Oracle Seminar - schedule updated May 1st


----- Original Message -----
From: "Thomas Jeff" <jeff.thomas@xxxxxxxxxxx>
To: <oracle-l@xxxxxxxxxxxxx>
Sent: Monday, May 17, 2004 12:28 PM
Subject: FW: Does primary key structure impact UPDATE performance?


See if this is easier to read.

-----Original Message-----
From: Thomas Jeff
Sent: Monday, May 17, 2004 6:25 AM
To: 'oracle-l@xxxxxxxxxxxxx'
Subject: RE: Does primary key structure impact UPDATE performance?


Yes, that's one row at a time.   There are no other indexes other then
the PK
constraint.  TA sample from the trace (following the binds) is like
this:

WAIT #1: nam=3D3D3D'db file sequential read' ela=3D3D3D 146 p1=3D3D3D12 =
=3D
p2=3D3D3D1831 =3D3D
p3=3D3D3D1 WAIT
#1: nam=3D3D3D'db file sequential read' ela=3D3D3D 136 p1=3D3D3D11 =
p2=3D3D3D27 =3D
p3=3D3D3D1 =3D3D
WAIT #1: nam=3D3D3D'db file sequential read' ela=3D3D3D 165 p1=3D3D3D49 =
=3D
p2=3D3D3D207213
p3=3D3D3D1 =3D3D WAIT #1: nam=3D3D3D'db file sequential read' ela=3D3D3D =
17462 =3D
p1=3D3D3D54
p2=3D3D3D20918 p3=3D3D3D1 =3D3D WAIT #1: nam=3D3D3D'db file sequential =
read' =3D
ela=3D3D3D 147
p1=3D3D3D54 p2=3D3D3D21512 p3=3D3D3D1 =3D3D WAIT #1: nam=3D3D3D'db file =
sequential =3D
read'
ela=3D3D3D 196 p1=3D3D3D12 p2=3D3D3D5854 p3=3D3D3D1 WAIT =3D3D
#1:
nam=3D3D3D'db file sequential read' ela=3D3D3D 142 p1=3D3D3D54 =
p2=3D3D3D20726 =3D
p3=3D3D3D1 =3D3D
WAIT #1: nam=3D3D3D'db file sequential read' ela=3D3D3D 142 p1=3D3D3D54 =
=3D
p2=3D3D3D21526
p3=3D3D3D1 =3D3D WAIT #1: nam=3D3D3D'db file sequential read' ela=3D3D3D =
147 =3D
p1=3D3D3D12
p2=3D3D3D5901 p3=3D3D3D1 WAIT =3D3D
#1:
nam=3D3D3D'db file sequential read' ela=3D3D3D 140 p1=3D3D3D12 =
p2=3D3D3D5911 =3D
p3=3D3D3D1 WAIT
=3D3D
#1:
nam=3D3D3D'db file sequential read' ela=3D3D3D 153 p1=3D3D3D11 =
p2=3D3D3D326 =3D
p3=3D3D3D1 WAIT
=3D3D
#1:
nam=3D3D3D'db file sequential read' ela=3D3D3D 148 p1=3D3D3D54 =
p2=3D3D3D20944 =3D
p3=3D3D3D1 =3D3D
WAIT #1: nam=3D3D3D'db file sequential read' ela=3D3D3D 143 p1=3D3D3D54 =
=3D
p2=3D3D3D21969
p3=3D3D3D1 =3D3D WAIT #1: nam=3D3D3D'db file sequential read' ela=3D3D3D =
151 =3D
p1=3D3D3D54
p2=3D3D3D20789 p3=3D3D3D1 =3D3D WAIT #1: nam=3D3D3D'db file sequential =
read' =3D
ela=3D3D3D 144
p1=3D3D3D54 p2=3D3D3D20755 p3=3D3D3D1 =3D3D WAIT #1: nam=3D3D3D'db file =
sequential =3D
read'
ela=3D3D3D 143 p1=3D3D3D12 p2=3D3D3D6052 p3=3D3D3D1 WAIT =3D3D
#1:
nam=3D3D3D'db file sequential read' ela=3D3D3D 137 p1=3D3D3D11 =
p2=3D3D3D415 =3D
p3=3D3D3D1 WAIT
=3D3D
#1:
nam=3D3D3D'db file sequential read' ela=3D3D3D 137 p1=3D3D3D54 =
p2=3D3D3D425 =3D
p3=3D3D3D1 WAIT
=3D3D
#1:
nam=3D3D3D'db file sequential read' ela=3D3D3D 124 p1=3D3D3D11 =
p2=3D3D3D426 =3D
p3=3D3D3D1 WAIT
=3D3D
#1:
nam=3D3D3D'db file sequential read' ela=3D3D3D 174 p1=3D3D3D54 =
p2=3D3D3D18965 =3D
p3=3D3D3D1 =3D3D
EXEC
#1:c=3D3D3D1720000,e=3D3D3D1691529,p=3D3D3D20,cr=3D3D3D2371,cu=3D3D3D1,mi=
s=3D3D3D0,r=3D3D=3D
3D1,dep=3D3D3D0
,=3D3D
og=3D3D3D4,tim=3D3D3D105920
2213148331 =3D3D20

If I'm reading this correctly, elapsed time was 1.7 seconds, required 20
PIO's and
2372 LIO's to execute this UPDATE, which updated one row.   =
p1=3D3D3D11/12 =3D
=3D3D
is
the index, p1=3D3D3D54
is the table.    The e, and cu/cr values are typical.


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