Reponse time issue with a simple qurey .

Question

hi all,
i started facing a strange issue with the below query form the biging of the month. we have a DW system for a banking domain and in that our accounts table from the first of this month is taking a huge amount of time to retive the data. if i query a back dated data say 31st of may that would be '310509' it give the result in less that 5 seconds. this is a very simple query which i am joing with a transaction table.
i assume the reason for the change in query reponce time is may be tha data from the beging of this month had a datablock extantion and this block is corrupted . kindly let me know what i am thinking is correct or there is another reaosn for this.
Also let me know what resolution should i take to resolve this issue.
my database version is Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Prod
Thanks in advance
SELECT * FROM
(select * from gtxn_dtl_v1 where batch_id='070609') a,
(select * from gacc_dtl_v1 where batch_id='070609') b
WHERE a.account_number = b.id
SELECT * FROM
(select * from gtxn_dtl_v1 where batch_id='310509') a,
(select * from gacc_dtl_v1 where batch_id='310509') b
WHERE a.account_number = b.id

Answer 1

Hemant K Chitale wrote:
I don't think that it is a simple query.
The two objects "gtxn_dtl_v1" and "gacc_dtl_v1" seem to be Views. So, the queries are probably involving joins of other tables.
Without an Execution Plan and information about table and index definitions and statistics on the tables and indexes, any attempt to answer your question would be meaningless.Both are tables. Explain plan is shown below:
SQL> explain plan for
  2  SELECT * FROM
  3  (select * from gtxn_dtl_v1 where batch_id='070609') a,
  4  (select * from gacc_dtl_v1 where batch_id='070609') b
  5   WHERE a.account_number = b.id;
Explained.
SQL> select * from table(dbms_xplan.display);
PLAN_TABLE_OUTPUT
Plan hash value: 4236620027
| Id  | Operation                    | Name        | Rows  | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT             |             |     1 |   601 |    38   (0)| 00:00:01 |
|   1 |  NESTED LOOPS                |             |     1 |   601 |    38   (0)| 00:00:01 |
|*  2 |   TABLE ACCESS BY INDEX ROWID| GACC_DTL_V1 |     1 |   313 |     4   (0)| 00:00:01 |
|*  3 |    INDEX RANGE SCAN          | IDX_ACC2_V1 |     1 |       |     3   (0)| 00:00:01 |
|*  4 |   TABLE ACCESS BY INDEX ROWID| GTXN_DTL_V1 |     1 |   288 |    34   (0)| 00:00:01 |
|*  5 |    INDEX RANGE SCAN          | IDX_TXN2_V1 |    55 |       |     8   (0)| 00:00:01 |
Predicate Information (identified by operation id):
   2 - filter("BATCH_ID"='070609')
   3 - access(SUBSTR("BATCH_ID",1,6)='070609')
   4 - filter("BATCH_ID"='070609' AND SUBSTR("GTXN_DTL_V1"."BATCH_ID",1,6)='070609')
   5 - access("GTXN_DTL_V1"."ACCOUNT_NUMBER"="GACC_DTL_V1"."ID")
       filter(SUBSTR("GTXN_DTL_V1"."ACCOUNT_NUMBER",1,3)=SUBSTR("GACC_DTL_V1"."ID",1
              ,3))
22 rows selected.
SQL> explain plan for
  2  SELECT * FROM
  3  (select * from gtxn_dtl_v1 where batch_id='310509') a,
  4  (select * from gacc_dtl_v1 where batch_id='310509') b
  5  WHERE a.account_number = b.id;
Explained.
SQL>  select * from table(dbms_xplan.display);
PLAN_TABLE_OUTPUT
Plan hash value: 1249675553
| Id  | Operation                     | Name            | Rows  | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT              |                 |     1 |   601 |   785   (1)| 00:00:10 |
|   1 |  TABLE ACCESS BY INDEX ROWID  | GACC_DTL_V1     |     1 |   313 |     4   (0)| 00:00:01 |
|   2 |   NESTED LOOPS                |                 |     1 |   601 |   785   (1)| 00:00:10 |
|   3 |    TABLE ACCESS BY INDEX ROWID| GTXN_DTL_V1     |   104 | 29952 |   368   (2)| 00:00:05 |
|*  4 |     INDEX RANGE SCAN          | IDX_TXN1        |   104 |       |   340   (2)| 00:00:05 |
|*  5 |    INDEX RANGE SCAN           | GACC_DTL_V1_IDX |     1 |       |     3   (0)| 00:00:01 |
Predicate Information (identified by operation id):
   4 - access("BATCH_ID"='310509')
       filter(SUBSTR("GTXN_DTL_V1"."BATCH_ID",1,6)='310509')
   5 - access("GTXN_DTL_V1"."ACCOUNT_NUMBER"="GACC_DTL_V1"."ID" AND "BATCH_ID"='310509')
       filter(SUBSTR("GACC_DTL_V1"."BATCH_ID",1,6)='310509' AND
              SUBSTR("GTXN_DTL_V1"."ACCOUNT_NUMBER",1,3)=SUBSTR("GACC_DTL_V1"."ID",1,3))
21 rows selected.
Indexes:
select i.index_name,index_type,i.table_name,num_rows,column_name,COLUMN_EXPRESSION
from all_indexes i,all_ind_columns c,ALL_IND_EXPRESSIONS e
where i.table_name in ('GACC_DTL_V1','GTXN_DTL_V')
and i.index_name = c.index_name
and e.index_name(+) = i.index_name;
INDEX_NAME     INDEX_TYPE          TABLE_NAME     NUM_ROWS     COLUMN_NAME     COLUMN_EXPRESSION
GACC_DTL_V1_IDX     NORMAL               GACC_DTL_V1     57190895     ID     
GACC_DTL_V1_IDX     NORMAL               GACC_DTL_V1     57190895     BATCH_ID     
IDX_ACC5_V1     NORMAL               GACC_DTL_V1     34524304     POSTING_RESTRICT     
IDX_ACC1_V1     NORMAL               GACC_DTL_V1     55919578     CATEGORY     
IDX_CUS5_V1     NORMAL               GACC_DTL_V1     54461378     CUSTOMER_NUMBER     
IDX_CUS6_V1     NORMAL               GACC_DTL_V1     3272052     LIMIT_REF     
IDX_ACC3_V1     FUNCTION-BASED NORMAL     GACC_DTL_V1     52940894     SYS_NC00099$     "CUSTOMER_NUMBER"||'.'||"LIMIT_REF"
IDX_ACC4_V1     FUNCTION-BASED NORMAL     GACC_DTL_V1     57238600     SYS_NC00100$     "CUSTOMER_NUMBER"||'.000'||"LIMIT_REF"
GACC_DTL_V1_IX2     FUNCTION-BASED NORMAL     GACC_DTL_V1     54448627     SYS_NC00101$     SUBSTR("ID",1,3)
IDX_ACC2_V1     FUNCTION-BASED NORMAL     GACC_DTL_V1     55566106     SYS_NC00102$     SUBSTR("BATCH_ID",1,6)Edited by: user577300 on Jun 10, 2009 11:41 PM
So many strange things here:
1.Query showing cost 38 is taking a long time  (hours). Other quey takes 5 sec
2. Plans are different.