Long running update statement needs a performance improve.

Question

Hi,
I have the following update statement which runs for over 3 hours and updates 215 million rows, is there anyway I can rewrite it so it performs better?
UPDATE TABLE1 v
        SET closs = (SELECT MIN(slloss)
                           FROM TABLE2 l
        WHERE polnum = slpoln
        AND      polren = slrenn
        AND      polseq = slseqn
        AND      vehnum = slvehn
        AND      linecvg = sllcvg);Here is the execution plan:
PLAN_TABLE_OUTPUT
| Id  | Operation                     | Name        | Rows  | Bytes | Cost (%CPU)|
|   0 | UPDATE STATEMENT              |             |   214M|  4291M|  2344K  (2)|
|   1 |  UPDATE                       | TABLE1      |       |       |            |
|   2 |   TABLE ACCESS FULL           | TABLE1      |   214M|  4291M|  2344K  (2)|
|   3 |   SORT AGGREGATE              |             |     1 |    21 |            |
|   4 |    TABLE ACCESS BY INDEX ROWID| TABLE2      |     1 |    21 |     5   (0)|
|   5 |     INDEX RANGE SCAN          | TABLE2_N2   |     2 |       |     3   (0)|
----------------------------------------------------------------------------------Here are create table statements for TABLE1(215million rows) and TABLE2(1million rows):
CREATE TABLE  TABLE2 (SLCLMN VARCHAR2(11 byte),
    SLFEAT NUMBER(2), SLPOLN NUMBER(9), SLRENN NUMBER(2),
    SLSEQN NUMBER(2), SLVEHN NUMBER(2), SLDRVN NUMBER(2),
    SLCVCD VARCHAR2(6 byte), SLLCVG NUMBER(4), SLSABB
    VARCHAR2(2 byte), SLPRCD VARCHAR2(3 byte), SLRRDT
    NUMBER(8), SLAYCD NUMBER(7), SLCITY VARCHAR2(28 byte),
    SLZIP5 NUMBER(5), SLCEDING VARCHAR2(1 byte), SLCEDELOSS
    VARCHAR2(1 byte), SLRISKTYPE VARCHAR2(1 byte), SLVEHDESIG
    VARCHAR2(1 byte)) 
    TABLESPACE S_DATA PCTFREE 10 PCTUSED 0 INITRANS 1
    MAXTRANS 255
    STORAGE ( INITIAL 106496K NEXT 0K MINEXTENTS 1 MAXEXTENTS
    2147483645 PCTINCREASE 0)
    NOLOGGING
    MONITORING;
CREATE TABLE  TABLE1 (POLNUM NUMBER(9) NOT NULL,
    POLREN NUMBER(2) NOT NULL, POLSEQ NUMBER(2) NOT NULL,
    VEHNUM NUMBER(2) NOT NULL, CVGCODE VARCHAR2(8 byte) NOT
    NULL, LINECVG NUMBER(4), MAINVEH CHAR(1 byte), MAINCVG
    CHAR(1 byte), CVGLIMIT VARCHAR2(13 byte), CVGDED
    VARCHAR2(10 byte), FULLCVG CHAR(1 byte), CVGGRP CHAR(4
    byte), CYCVG CHAR(1 byte), POLTYPE CHAR(1 byte),
    CHANNEL CHAR(2 byte), UWTIER VARCHAR2(6 byte), SUBTIER
    VARCHAR2(6 byte), THITIER VARCHAR2(3 byte), COMPGRP
    VARCHAR2(8 byte), PRODGRP VARCHAR2(6 byte), UWSYS
    VARCHAR2(6 byte), BRAND VARCHAR2(8 byte), COMP NUMBER(2),
    STATE CHAR(2 byte), PROD CHAR(3 byte), RRDATE DATE,
    STATENUM NUMBER(2), EFT_BP CHAR(1 byte), AGYCODE
    NUMBER(7), AGYSUB CHAR(3 byte), AGYCLASS CHAR(1 byte),
    CLMAGYCODE NUMBER(7), AGYALTCODE VARCHAR2(25 byte),
    AGYRELATION VARCHAR2(10 byte), RATECITY VARCHAR2(28 byte),
    RATEZIP NUMBER(5), RATETERR NUMBER, CURTERR NUMBER,
    CURRRPROD CHAR(6 byte), CURRRDATE DATE, RATESYMB NUMBER,
    SYMBTYPE CHAR(1 byte), CVGTERR NUMBER(3), CVGSYMB
    NUMBER(3), VEHTERR NUMBER, VEHYEAR NUMBER, VEHMAKE
    VARCHAR2(6 byte), VEHMODEL VARCHAR2(10 byte), VEHSUBMOD
    VARCHAR2(10 byte), VEHBODY VARCHAR2(6 byte), VEHVIN
    VARCHAR2(10 byte), VEHAGE NUMBER(3), VEHSYMB NUMBER,
    DRVNUM NUMBER, DUMMYDRV CHAR(1 byte), DRVAGE NUMBER(3),
    DRVSEX VARCHAR2(1 byte), DRVMS VARCHAR2(1 byte), DRVPTS
    NUMBER(3), DRVPTSDD NUMBER(3), DRVGRP CHAR(7 byte),
    DRVSR22 VARCHAR2(1 byte), DRVVTIER CHAR(2 byte),
    BUSUSESUR CHAR(1 byte), EXCLDRVSUR CHAR(1 byte),
    CSCODED NUMBER(5), CSACTUAL NUMBER(5), CSOVERRD
    NUMBER(5), ANNMILES NUMBER(6), DLORIGDATE DATE,
    DLLASTDATE DATE, DLMONTHS NUMBER(6), MATUREDSC CHAR(1
    byte), PERSISTDSC CHAR(1 byte), ANNUALMILES_RANGE
    VARCHAR2(25 byte), CEDEDLOSS VARCHAR2(1 byte), CEDEDPOL
    VARCHAR2(1 byte), CEDEDCVG VARCHAR2(1 byte),
    CONSTRAINT TABLE1_PK PRIMARY KEY(POLNUM, POLREN,
    POLSEQ, VEHNUM, CVGCODE)
    USING INDEX 
    TABLESPACE V_INDEX
    STORAGE ( INITIAL 3874816K NEXT 0K MINEXTENTS 1 MAXEXTENTS
    2147483645 PCTINCREASE 0) PCTFREE 10 INITRANS 2 MAXTRANS 255)
    TABLESPACE U_DATA PCTFREE 10 PCTUSED 0 INITRANS 1
    MAXTRANS 255
    STORAGE ( INITIAL 4194304K NEXT 0K MINEXTENTS 1 MAXEXTENTS
    2147483645 PCTINCREASE 0)
    NOLOGGING
    MONITORING;Thank you very much!

Answer 1

user6053424 wrote:
Hi,
I have the following update statement which runs for over 3 hours and updates 215 million rows, is there anyway I can rewrite it so it performs better?
UPDATE TABLE1 v
SET closs = (SELECT MIN(slloss)
FROM TABLE2 l
WHERE polnum = slpoln
AND      polren = slrenn
AND      polseq = slseqn
AND      vehnum = slvehn
AND      linecvg = sllcvg);
Are you trying to perform a correlated update? If so, you can perform something similar to;
Sample data;
create table t1 as (
   select 1 id, 10 val from dual union all
   select 1 id, 10 val from dual union all
   select 2 id, 10 val from dual union all
   select 2 id, 10 val from dual union all
   select 2 id, 10 val from dual);
Table created
create table t2 as (
   select 1 id, 100 val from dual union all
   select 1 id, 200 val from dual union all
   select 2 id, 500 val from dual union all
   select 2 id, 600 val from dual);
Table createdThe MERGE will update each row based on the maximum for each ID;
merge into t1
using (select id, max(val) max_val
       from t2
       group by id) subq
on (t1.id = subq.id)
when matched then update
    set t1.val = subq.max_val;
Done
select * from t1;
        ID        VAL
         1        200
         1        200
         2        600
         2        600
         2        600If you want all rows updated to the same value then remove the ID grouping from the subquery and from the ON clause.