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This blog contains things about PeopleSoft that DBAs might find interesting.
Or then again they might not!
Non-PeopleSoft Oracle stuff is at blog.go-faster.co.uk.
Updated: 17 hours 12 min ago

Who is using this index?

Wed, 2014-09-03 04:30
Or, to put it another way, I want to change or drop this index, who and what will I impact?
The Challenge The problem that I am going to outline is certainly not exclusive to PeopleSoft, but I am going to illustrate it with examples from PeopleSoft. I often find tables with far more indexes than are good for them.
  • The Application Designer tool makes it very easy for developers to add indexes to tables. Sometimes, too easy!
  • Sometimes, DBAs are too quick to unquestioningly follow the advice of the Oracle tuning advisor to add indexes.
Recently, I have been working on 3 different PeopleSoft Financials systems where I have found major tables with a host of indexes.

There are several concerns:
  • Indexes are maintained during data modification. The more indexes you have, the greater the overhead. 
  • The more indexes you have, particularly if they lead on the same columns, the more likely Oracle is to use the wrong one, resulting in poorer performance.
  • There is of course also a space overhead for each index, but this is often of less concern. 
If you can get rid of an index, Oracle doesn't store, maintain or use it. 
In some cases, I have wanted to remove unnecessary indexes, and in others to adjust indexes. However, this immediately raises the question of where are these indexes used, and who will be impacted by the change. Naturally, I turn to the Active Session History (ASH) to help me find the answers. Index Maintenance Overhead during DDL ASH reports the object number, file number, block number and (from 11g) row number within the block being accessed by physical file operations. However, the values reported in v$active_session_history (and later other views) are not reliable for other events because they are merely left over from the previous file event that reported them. So, we can profile the amount of time spent on physical I/O on different tables and indexes, but not for other forms of DB Time, such as CPU time, spent accessing the blocks in the buffer cache.
Let me take an extreme example from PeopleSoft Global Payroll. The table PS_GP_RSLT_ACUM is one of the principal result tables. It has only a single unique index (with the same name). The table is populated with the simplest of insert statements.
INSERT /*GPPRDMGR_I_ACUM*/ INTO PS_GP_RSLT_ACUM
(CAL_RUN_ID ,EMPLID ,EMPL_RCD ,GP_PAYGROUP ,CAL_ID ,RSLT_SEG_NUM ,PIN_NUM ,EMPL_RCD_ACUM ,ACM_FROM_DT ,ACM_THRU_DT ,USER_KEY1 ,USER_KEY2 ,USER_KEY3 ,USER_KEY4 ,USER_KEY5 ,USER_KEY6 ,SLICE_BGN_DT ,SLICE_END_DT ,COUNTRY ,ACM_TYPE ,ACM_PRD_OPTN ,CALC_RSLT_VAL ,CALC_VAL ,USER_ADJ_VAL ,PIN_PARENT_NUM ,CORR_RTO_IND ,ORIG_CAL_RUN_ID ,SEQ_NUM8 ,VALID_IN_SEG_IND ,CALLED_IN_SEG_IND )
VALUES
(:1,:2,:3,:4,:5,:6,:7,:8,:9,:10,:11,:12,:13,:14,:15,:16,:17,:18,:19,:20,:21,:22,:23,:24,:25,:26,:27,:28,:29,:30)
I can profile the ASH data for just this statement over the last week on a production system. Note that DBA_OBJECTS and DBA_DATA_FILES are outer joined to the ASH data and only matched for events like 'db file%'
SELECT o.object_type, o.object_name
, f.tablespace_name, NVL(h.event,'CPU+CPU Wait') event
, SUM(10) ash_Secs
FROM dba_hist_Active_sess_history h
LEFT OUTER JOIN dba_objects o
ON o.object_id = h.current_obj#
AND h.event like 'db file%'
LEFT OUTER JOIN dba_data_files f
ON f.file_id = h.current_file#
AND h.event like 'db file%'
WHERE h.sql_id = '4ru0618dswz3y'
AND h.sample_time >= sysdate-7
GROUP BY o.object_type, o.object_name, h.event, f.tablespace_name
ORDER BY ash_secs DESC
/
A full payroll calculation inserts over 3 million rows on this particular system. The calculation is run incrementally several times per week during which old rows are deleted and newly recalculated rows inserted.  Looking at just this insert statement:
  • 30% of the time is spent on CPU operations, we cannot profile that time further with ASH.
  • 38% of the time is spent reading from the table and index, yet this is a simple INSERT … VALUES statement.
OBJECT_TYPE         OBJECT_NAME        TABLESPACE_NAME EVENT                      ASH_SECS
------------------- ------------------ --------------- ------------------------ ----------
CPU+CPU Wait 1040
UNDOTBS1 db file sequential read 900
INDEX SUBPARTITION PS_GP_RSLT_ACUM GP201408IDX db file sequential read 750
TABLE SUBPARTITION PS_GP_RSLT_ACUM GP201408TAB db file sequential read 550
gc current grant 2-way 70
cursor: pin S wait on X 60
db file sequential read 10
buffer exterminate 10
row cache lock 10
----------
3400
More time is spent reading the index than the table.  That is not a surprise.  When you insert a row into a table, you also insert it into the index. Rows in index leaf blocks are ordered by the key columns, and the new entry must go into the right place, so you have to read down the index from the root block, through the branch blocks, to find the correct leaf block for the new entry.
[Digression: Counter-intuitively index compression can improve DML performance. It does for this index.  The overhead of the compression processing can be outweighed by the saving in physical I/O.  It depends.]
Profile Physical I/O by Object I can twist this query around and profile DB_TIME by object for 'db file%' events
SELECT o.object_type, o.object_name, sum(10) ash_secs
FROM dba_hist_active_sess_history h
, dba_objects o
WHERE o.object_id = h.current_obj#
AND h.event LIKE 'db file%'
AND h.sample_time > sysdate-7
GROUP BY o.object_type, o.object_name
ORDER BY ash_Secs DESC
Now I can see upon which objects the most time is spent on physical I/O.
OBJECT_TYP OBJECT_NAME          ASH_SECS
---------- ------------------ ----------
TABLE PS_ITEM 101130
INDEX PS_WS_ITEM 98750
TABLE PS_PROJ_RESOURCE 97410
TABLE PS_BI_LINE 85040
INDEX PSAPSAPMSGSUBCON 75070
TABLE PS_BI_HDR 37230
TABLE PS_RS_ASSIGNMENT 29460
INDEX PS_PSAPMSGPUBHDR 23230
INDEX PS_BI_ACCT_ENTRY 21490
TABLE PS_VOUCHER 21330
TABLE PS_VCHR_ACCTG_LINE 21250
TABLE PS_BI_ACCT_ENTRY 18860

----------
sum 1382680
This is a worthwhile exercise, it shows the sources of physical I/O in an application.

However, if you want to find where an index is used, then this query will also identify SQL_IDs where the index is either used in the query or maintained by DML. If I am interested in looking for places where changing or deleting an index could have an impact then I am only interested in SQL query activity. ASH samples which relate to index maintenance are a false positive. Yet, I cannot simply eliminate ASH samples where the SQL_OPNAME is not SELECT because the index may be used in a query within the DML statement.

Another problem with this method is that it matches SQL to ASH by object ID. If someone has rebuilt an index, then its object number changes.

A different approach is required.
Index Use from SQL Plans Captured by AWR During an AWR snapshot the top-n SQL statements by each SQL criteria in the AWR report (Elapsed Time, CPU Time, Parse Calls, Shareable Memory, Version Count) , see dbms_workload_repository. The SQL plans are exposed by the view DBA_HIST_SQL_PLAN.

On PeopleSoft systems, I generally recommend decreasing the snapshot interval from the default of 60 minutes to 15. The main reason is that SQL gets aged out of the library cache very quickly in PeopleSoft systems. They generate lots of dynamic code, often with literal values rather than bind variables. Cursor sharing is not recommended for PeopleSoft, so different bind variables result in different SQL_IDs. The dynamic code also results in different SQL IDs even with cursor sharing. Therefore, increasing the snapshot frequency means that will capture more SQL statement. This will increase total volume of the AWR repository simply because there are more snapshots. However, the overall volume of ASH data captured does not change, it just gets copied to the repository earlier.

On DBA_HIST_SQL_PLAN the object ID, owner, type and name are recorded, so I can find the plans which referenced a particular object. I am going to carry on with the example from a PeopleSoft Financials system, and look at indexes on the PS_PROJ_RESOURCE table.

These are some of the indexes on PS_PROJ_RESOURCE. We have 4 indexes that all lead on PROCESS_INSTANCE. I suspect that not all are essential, but I need to work out what is using them, and which one I should retain.
                          Col
INDEX_NAME Pos COLUMN_NAME COLUMN_EXPRESSION
------------------ ---------- -------------------- ----------------------------------

PSJPROJ_RESOURCE 1 PROCESS_INSTANCE
2 BUSINESS_UNIT_GL
3 BUSINESS_UNIT
4 PROJECT_ID
5 ACTIVITY_ID
6 CUST_ID

PSLPROJ_RESOURCE 1 PROCESS_INSTANCE
2 EMPLID
3 EMPL_RCD
4 TRANS_DT

PSMPROJ_RESOURCE 1 PROCESS_INSTANCE
2 BUSINESS_UNIT
3 PROJECT_ID
4 ACTIVITY_ID
5 RESOURCE_ID

PSNPROJ_RESOURCE 1 PROCESS_INSTANCE
2 BUSINESS_UNIT
3 TIME_RPTG_CD

I find it easier to extract the ASH data to my own working storage table. For each index on PS_PROJ_RESOURCE, I am going to extract a distinct list of plan hash values. I will then extract all ASH data for those plans. Note, that I have not joined the SQL_ID on DBA_HIST_SQL_PLAN. That is because different SQL_IDs can produce the same execution plan. The plan is equally valid for all SQL_IDs that produce the plan, not just the one where the SQL_ID also matches.
DROP TABLE my_ash purge
/
CREATE TABLE my_ash COMPRESS AS
WITH p AS (
SELECT DISTINCT p.plan_hash_value, p.object#, p.object_owner, p.object_type, p.object_name
FROM dba_hist_sql_plan p
WHERE p.object_name like 'PS_PROJ_RESOURCE'
AND p.object_type LIKE 'INDEX%'
AND p.object_owner = 'SYSADM'
)
SELECT p.object# object_id, p.object_owner, p.object_type, p.object_name
, h.*
FROM dba_hist_active_sess_history h
, p
WHERE h.sql_plan_hash_value = p.plan_hash_value
/
I am fortunate that PeopleSoft is a well instrumented application. Module and Action are set to fairly sensible values that will tell me whereabouts in the application the ASH sample relates. In the following query, I have omitted any ASH data generated by SQL*Plus, Toad, or SQL Developer, and also any generated by Oracle processes to prevent statistics collection jobs being included.
Set pages 999 lines 150 trimspool on
break on object_name skip 1
compute sum of ash_secs on object_name
column ash_secs heading 'ASH|Secs' format 9999999
column module format a20
column action format a32
column object_name format a18
column max_sample_time format a19 heading 'Last|Sample'
column sql_plans heading 'SQL|Plans' format 9999
column sql_execs heading 'SQL|Execs' format 99999
WITH h AS (
SELECT object_name
, CASE WHEN h.module IS NULL THEN REGEXP_SUBSTR(h.program,'[^.@]+',1,1)
WHEN h.module LIKE 'PSAE.%' THEN REGEXP_SUBSTR(h.module,'[^.]+',1,2)
ELSE REGEXP_SUBSTR(h.program,'[^.@]+',1,1)
END as module
, CASE WHEN h.action LIKE 'PI=%' THEN NULL
ELSE h.action
END as action
, CAST(sample_time AS DATE) sample_time
, sql_id, sql_plan_hash_value, sql_exec_id
FROM my_ash h
)
SELECT object_name, module, action
, sum(10) ash_secs
, COUNT(DISTINCT sql_plan_hash_value) sql_plans
, COUNT(DISTINCT sql_id||sql_plan_hash_value||sql_exec_id) sql_execs
, MAX(sample_time) max_sample_time
FROM h
WHERE NOT LOWER(module) IN('oracle','toad','sqlplus','sqlplusw')
AND NOT LOWER(module) LIKE 'sql%'
GROUP BY object_name, module, action
ORDER BY SUBSTR(object_name,4), object_name, ash_Secs desc
/
Spool off
I now have a profile of how much each index is used. In this particular case I found something using every index.  It is possible that you will not find anything that uses some indexes.
                                                                             ASH   SQL    SQL Last
OBJECT_NAME MODULE ACTION Secs Plans Execs Sample
------------------ -------------------- -------------------------------- ------- ----- ------ -------------------

PSJPROJ_RESOURCE PC_TL_TO_PC GFCPBINT_AE.CallmeA.Step24.S 7300 1 66 06:32:57 27/08/2014
PC_PRICING GFCPBINT_AE.CallmeA.Step24.S 40 1 2 08:38:57 22/08/2014
****************** -------
sum 7340

PSLPROJ_RESOURCE PC_TL_TO_PC GFCPBINT_AE.CallmeA.Step28.S 1220 1 53 06:33:17 27/08/2014
****************** -------
sum 1220

PSMPROJ_RESOURCE PC_TL_TO_PC GFCPBINT_AE.XxBiEDM.Step07.S 60 2 6 18:35:18 20/08/2014
****************** -------
sum 60

PSNPROJ_RESOURCE PC_TL_TO_PC GFCPBINT_AE.CallmeA.Step26.S 6720 1 49 18:53:58 26/08/2014
PC_TL_TO_PC GFCPBINT_AE.CallmeA.Step30.S 3460 1 60 06:33:27 27/08/2014
GFCOA_CMSN GFCOA_CMSN.01INIT.Step01.S 2660 1 47 19:19:40 26/08/2014
PC_TL_TO_PC GFCPBINT_AE.CallmeA.Step06.S 1800 1 52 18:53:28 26/08/2014
PC_TL_TO_PC GFCPBINT_AE.CallmeG.Step01.S 1740 1 61 06:34:17 27/08/2014
PC_TL_TO_PC GFCPBINT_AE.CallmeA.Step02.S 1680 1 24 18:53:18 26/08/2014
PC_TL_TO_PC GFCPBINT_AE.CallmeA.Step10.S 1460 1 33 17:26:26 22/08/2014
PC_TL_TO_PC GFCPBINT_AE.CallmeA.Step08.S 920 1 26 17:26:16 22/08/2014
PC_TL_TO_PC GFCPBINT_AE.CallmeA.Step36.S 460 1 18 18:26:38 20/08/2014
PC_TL_TO_PC GFCPBINT_AE.CallmeA.Step09.S 420 1 16 06:33:07 27/08/2014
PC_PRICING GFCPBINT_AE.CallmeG.Step01.S 200 1 10 08:09:55 22/08/2014
PC_AP_TO_PC GFCPBINT_AE.CallmeH.Step00A.S 170 1 17 21:53:26 21/08/2014
PC_PRICING GFCPBINT_AE.CallmeA.Step36.S 20 1 1 08:02:46 05/08/2014
PC_PRICING GFCPBINT_AE.CallmeA.Step30.S 20 1 1 13:42:48 04/08/2014
PC_PRICING GFCPBINT_AE.CallmeA.Step06.S 20 1 1 15:58:35 28/07/2014
PC_TL_TO_PC GFCPBINT_AE.CallmeA.Pseudo.S 20 1 1 19:45:11 06/08/2014
****************** -------
sum 21770

The next stage is to look at individual SQL statements This query looks for which SQL statement is using a particular index on PROJ_RESOURCE. If I can't find the SQL which cost the most time, then just choose another SQL with the same plan
  • I have found that sometimes a plan is captured by AWR, but the SQL statement is not. Personally, I think that is a bug. Working around it has made the following query quite complicated.
Break on object_name skip 1 
column ash_secs heading 'ASH|Secs' format 9999999
Set long 50000
Column cmd Format a200
Spool dmk

WITH h AS (
SELECT h.object_name
, CASE WHEN h.module IS NULL THEN REGEXP_SUBSTR(h.program,'[^.@]+',1,1)
WHEN h.module LIKE 'PSAE.%' THEN REGEXP_SUBSTR(h.module,'[^.]+',1,2)
ELSE REGEXP_SUBSTR(h.program,'[^.@]+',1,1)
END as module
, CASE WHEN h.action LIKE 'PI=%' THEN NULL
ELSE h.action
END as action
, h.sql_id, h.sql_plan_hash_value
, t.command_type –-not null if plan and statement captured
FROM my_ash h
LEFT OUTER JOIN (
SELECT t1.*
FROM dba_hist_sqltext t1
, dba_hist_sql_plan p1
WHERE t1.sql_id = p1.sql_id
AND p1.id = 1
) t
ON t.sql_id = h.sql_id
AND t.dbid = h.dbid
WHERE h.object_name IN('PSMPROJ_RESOURCE')
AND h.object_Type = 'INDEX'
AND h.object_owner = 'SYSADM'
And NOT LOWER(module) IN('oracle','toad','sqlplus','sqlplusw')
AND NOT LOWER(module) LIKE 'sql%'
), x AS ( --aggregate DB time by object and statement
SELECT object_name, sql_id, sql_plan_hash_value
, sum(10) ash_secs
, 10*COUNT(command_type) sql_secs --DB time for captured statements only
FROM h
WHERE NOT LOWER(module) IN('oracle','toad','sqlplus','sqlplusw')
AND NOT LOWER(module) LIKE 'sql%'
GROUP BY object_name, sql_id, sql_plan_hash_value
), y AS ( --rank DB time per object and plan
SELECT object_name, sql_id, sql_plan_hash_value
, ash_secs
, SUM(ash_secs) OVER (PARTITION BY object_name, sql_plan_hash_value) plan_ash_secs
, row_number() OVER (PARTITION BY object_name, sql_plan_hash_value ORDER BY sql_Secs DESC) ranking
FROM x
), z AS (
SELECT object_name
, CASE WHEN t.sql_text IS NOT NULL THEN y.sql_id
ELSE (SELECT t1.sql_id
FROM dba_hist_sqltext t1
, dba_hist_sql_plan p1
WHERE t1.sql_id = p1.sql_id
AND p1.plan_hash_value = y.sql_plan_hash_value
AND rownum = 1) --if still cannot find statement just pick any one
END AS sql_id
, y.sql_plan_hash_value, y.plan_ash_secs
, CASE WHEN t.sql_text IS NOT NULL THEN t.sql_text
ELSE (SELECT t1.sql_Text
FROM dba_hist_sqltext t1
, dba_hist_sql_plan p1
WHERE t1.sql_id = p1.sql_id
AND p1.plan_hash_value = y.sql_plan_hash_value
AND rownum = 1) --if still cannot find statement just pick any one
END AS sql_text
from y
left outer join dba_hist_sqltext t
on t.sql_id = y.sql_id
WHERE ranking = 1 --captured statement with most time
)
SELECT *
--'SELECT * FROM table(dbms_xplan.display_awr('''||sql_id||''','||sql_plan_hash_value||',NULL,''ADVANCED''))/*'||object_name||':'||plan_ash_Secs||'*/;' cmd
FROM z
ORDER BY object_name, plan_ash_secs DESC
/
Spool off
So now I can see the individual SQL statements.
PSJPROJ_RESOURCE   f02k23bqj0xc4          3393167302          7340 UPDATE PS_PROJ_RESOURCE C SET (C.Operating_Unit, C.CHARTFIELD1, C.PRODUCT, C.CLA
SS_FLD, C.CHARTFIELD2, C.VENDOR_ID, C.contract_num, C.contract_line_num, …

PSLPROJ_RESOURCE 2fz0gcb2774y0 821236869 1220 UPDATE ps_proj_resource p SET p.deptid = NVL (( SELECT j.deptid FROM ps_job j WH
ERE j.emplid = p.emplid AND j.empl_rcd = p.empl_rcd AND j.effdt = ( SELECT MAX (…

PSMPROJ_RESOURCE 96cdkb7jyq863 338292674 50 UPDATE PS_GFCBI_EDM_TA04 a SET a.GFCni_amount = ( SELECT x.resource_amount FROM
PS_PROJ_RESOURCE x WHERE x.process_instance = …

1kq9rfy8sb8d4 4135884683 10 UPDATE PS_GFCBI_EDM_TA04 a SET a.GFCni_amount = ( SELECT x.resource_amount FROM
PS_PROJ_RESOURCE x WHERE x.process_instance = …

PSNPROJ_RESOURCE ga2x2u4jw9p0x 2282068749 6760 UPDATE PS_PROJ_RESOURCE P SET (P.RESOURCE_TYPE, P.RESOURCE_SUB_CAT) = …

9z5qsq6wrr7zp 3665912247 3500 UPDATE PS_PROJ_RESOURCE P SET P.TIME_SHEET_ID = …
If I replace the last select clause with the commented line, then I can generate the commands to extract the statement and plan from the AWR repository.
SELECT * FROM table(dbms_xplan.display_awr('45ggt0yfrh5qp',3393167302,NULL,'ADVANCED'))/*PSJPROJ_RESOURCE:7340*/;

SELECT * FROM table(dbms_xplan.display_awr('8ntxj3694r6kg',821236869,NULL,'ADVANCED'))/*PSLPROJ_RESOURCE:1220*/;

SELECT * FROM table(dbms_xplan.display_awr('96cdkb7jyq863',338292674,NULL,'ADVANCED'))/*PSMPROJ_RESOURCE:50*/;

SELECT * FROM table(dbms_xplan.display_awr('1kq9rfy8sb8d4',4135884683,NULL,'ADVANCED'))/*PSMPROJ_RESOURCE:10*/;

SELECT * FROM table(dbms_xplan.display_awr('ga2x2u4jw9p0x',2282068749,NULL,'ADVANCED'))/*PSNPROJ_RESOURCE:6760*/;
SELECT * FROM table(dbms_xplan.display_awr('9z5qsq6wrr7zp',3665912247,NULL,'ADVANCED'))/*PSNPROJ_RESOURCE:3500*/;
SELECT * FROM table(dbms_xplan.display_awr('b28btd6k3x8jt',1288409804,NULL,'ADVANCED'))/*PSNPROJ_RESOURCE:3060*/;
SELECT * FROM table(dbms_xplan.display_awr('avs70c19khxmw',2276811880,NULL,'ADVANCED'))/*PSNPROJ_RESOURCE:2660*/;
SELECT * FROM table(dbms_xplan.display_awr('b78qhsch85g4a',1019599680,NULL,'ADVANCED'))/*PSNPROJ_RESOURCE:1960*/;
SELECT * FROM table(dbms_xplan.display_awr('65kq2v1ubybps',3138703971,NULL,'ADVANCED'))/*PSNPROJ_RESOURCE:1820*/;
SELECT * FROM table(dbms_xplan.display_awr('1dj17ra70c801',1175874548,NULL,'ADVANCED'))/*PSNPROJ_RESOURCE:1460*/;
SELECT * FROM table(dbms_xplan.display_awr('3w71v896s7m5d',3207074729,NULL,'ADVANCED'))/*PSNPROJ_RESOURCE:500*/;
SELECT * FROM table(dbms_xplan.display_awr('35mz5bw7p5ubw',2447377432,NULL,'ADVANCED'))/*PSNPROJ_RESOURCE:170*/;
Ultimately, I have needed to look through the SQL plans that use an index to decide whether I need to keep that index or decide whether the statement would perform adequately using another index. In this case, on this particular system, I think the index PSMPROJ_RESOURCE would be adequate for this statement, and I would consider dropping PSLPROJ_RESOURCE.
>SELECT * FROM table(dbms_xplan.display_awr('8ntxj3694r6kg',821236869,NULL,'ADVANCED'))/*PSLPROJ_RESOURCE:1220*/;
--------------------
UPDATE ps_proj_resource p SET p.deptid = NVL (( SELECT j.deptid FROM
ps_job j WHERE j.emplid = p.emplid AND j.empl_rcd = p.empl_rcd AND
j.effdt = ( SELECT MAX (j1.effdt) FROM ps_job j1 WHERE j1.emplid =
j.emplid AND j1.empl_rcd = j.empl_rcd AND j1.effdt <= p.trans_dt) AND
j.effseq = ( SELECT MAX (j2.effseq) FROM ps_job j2 WHERE j2.emplid =
j.emplid AND j2.empl_rcd = j.empl_rcd AND j2.effdt = j.effdt)),
p.deptid )
WHERE p.process_instance = …
AND EXISTS ( SELECT
j.deptid FROM ps_job j WHERE j.emplid = p.emplid AND j.empl_rcd =
p.empl_rcd AND j.effdt = ( SELECT MAX (j1.effdt) FROM ps_job j1 WHERE
j1.emplid = j.emplid AND j1.empl_rcd = j.empl_rcd AND j1.effdt <=
p.trans_dt) AND j.effseq = ( SELECT MAX (j2.effseq) FROM ps_job j2
WHERE j2.emplid = j.emplid AND j2.empl_rcd = j.empl_rcd AND j2.effdt =
j.effdt))

Plan hash value: 821236869

-----------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
-----------------------------------------------------------------------------------------
| 0 | UPDATE STATEMENT | | | | 63104 (100)| |
| 1 | UPDATE | PS_PROJ_RESOURCE | | | | |
| 2 | INDEX RANGE SCAN | PSLPROJ_RESOURCE | 365 | 11315 | 22 (0)| 00:00:01 |
| 3 | INDEX RANGE SCAN | PSAJOB | 1 | 23 | 3 (0)| 00:00:01 |
| 4 | SORT AGGREGATE | | 1 | 20 | | |
| 5 | INDEX RANGE SCAN| PSAJOB | 1 | 20 | 3 (0)| 00:00:01 |
| 6 | SORT AGGREGATE | | 1 | 23 | | |
| 7 | INDEX RANGE SCAN| PSAJOB | 1 | 23 | 3 (0)| 00:00:01 |
| 8 | INDEX RANGE SCAN | PSAJOB | 1 | 29 | 3 (0)| 00:00:01 |
| 9 | SORT AGGREGATE | | 1 | 20 | | |
| 10 | INDEX RANGE SCAN | PSAJOB | 1 | 20 | 3 (0)| 00:00:01 |
| 11 | SORT AGGREGATE | | 1 | 23 | | |
| 12 | INDEX RANGE SCAN | PSAJOB | 1 | 23 | 3 (0)| 00:00:01 |
-----------------------------------------------------------------------------------------

I carried on with examination of SQL statements and execution plans to determine whether each index is really needed or another index (or even no index at all) would do as well.  This decision also requires some background knowledge about the application. Eventually, I decided that I want drop the J, L and N indexes on PROJ_RESOURCE and just keep M. 
Limitations of Method
    AWR does not capture all SQLs, nor all SQL plans. First the SQL has to be in the library cache and then it must be one of the top-n. A SQL that is efficient because it uses an appropriate index may not be captured, and will not be detected by this approach. This might lead you to erronously believe that the index could be dropped.
      ASH data is purged after a period of time, by default 31 days. If an index is only used by a process that has not run within the retention period, then it will not be detected by this approach. This is another reason to retain ASH and AWR in a repository for a longer period. I have heard 400 days suggested, so that you have ASH for a year and a month.
        • However, this also causes the SYSAUX tablespace to be become very large, so I would suggest regularly moving the data to a separate database. I know one customer who has built a central AWR repository for all their production and test databases and automated regular transfer of data. That repository has been of immense diagnostic value.
        [Update] This analysis will not detect index use in support constraint validation (PeopleSoft doesn't use database referential integrity constraints).  As Mark Farnham points out below, that may be a reason for retaining a particular index.Getting Rid of Indexes Obviously any index changes need to be tested carefully in all the places that reference the index, but on the other hand it is not viable to do a full regression test every time you want to change an index.
          Therefore, if all the testing is successful and you decide to go ahead and drop the index in production, you might prefer to make it invisible first for a while before actually dropping it. It is likely that the indexes you choose to examine are large and will take time to rebuild. An invisible index will not be used by the optimizer, but it will continue to be maintained during DML. If there are any unfortunate consequences, you can immediately make the index visible without having to rebuild it.
            ©David Kurtz, Go-Faster Consultancy Ltd.

            To Hint or not to hint (Application Engine), that is the question

            Mon, 2014-08-25 12:36
            Over the years Oracle has provided a number of plan stability technologies to control how SQL statements are executed.  At the risk of over simplification, Outlines (deprecated in 11g), Profiles, Baselines and Patches work by injecting a set of hints into a SQL statement at parse time.  There is quite a lot of advice from Oracle to use these technologies to fix errant execution plans rather than hint the application.  I think it is generally good advice, however, there are times when this approach does not work well with PeopleSoft, and that is due to the behaviour and structure of PeopleSoft rather than the Oracle database.

            It is possible to produce a SQL profile from a plan captured by AWR.  A part of distribution for the SQLT Diagnostic Tool (Doc ID 215187.1) is a script called coe_xfr_sql_profile.sql written by Carlos Sierra.
            The only thing I would change in the delivered script, (for use with PeopleSoft and as suggested in a comment) is to create the profile with FORCE_MATCHING so that similar statements with different literal values still match. 
            The Slings and Arrows of outrageous execution plans Let's take an example of a statement (from the vanilla Financials product that has not been customised) that performed poorly because it didn't generate a good execution plan (although I have cut out most of the statement for readability.  Note, that it references instance 5 of PeopleTools temporary record CA_SUM_TAO.
            INSERT INTO PS_CA_SUM_RC_TAO5 (…) SELECT

            FROM PS_CA_PR_SUMM A, PS_CA_SUM_TAO5 B , PS_CA_SUM_IN_USE C WHERE

            B.PROCESS_INSTANCE = 51381955 AND C.IN_USE_FLAG = 'Y'

            Plan hash value: 2039212279
            ----------------------------------------------------------------------------------------------------
            | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
            ----------------------------------------------------------------------------------------------------
            | 0 | INSERT STATEMENT | | | | 14424 (100)| |
            | 1 | LOAD TABLE CONVENTIONAL | | | | | |
            | 2 | NESTED LOOPS | | | | | |
            | 3 | NESTED LOOPS | | 1 | 430 | 14424 (1)| 00:02:54 |
            | 4 | NESTED LOOPS | | 1 | 318 | 14421 (1)| 00:02:54 |
            | 5 | TABLE ACCESS FULL | PS_CA_SUM_IN_USE | 1 | 85 | 14420 (1)| 00:02:54 |
            | 6 | TABLE ACCESS BY INDEX ROWID| PS_CA_SUM_TAO5 | 1 | 233 | 1 (0)| 00:00:01 |
            | 7 | INDEX UNIQUE SCAN | PS_CA_SUM_TAO5 | 1 | | 0 (0)| |
            | 8 | INDEX RANGE SCAN | PSACA_PR_SUMM | 1 | | 2 (0)| 00:00:01 |
            | 9 | TABLE ACCESS BY INDEX ROWID | PS_CA_PR_SUMM | 1 | 112 | 3 (0)| 00:00:01 |
            ----------------------------------------------------------------------------------------------------
            However, below is the plan we get on instance 4.  We get this plan because there is already a profile that has been applied in the past, but now we are on a different non-shared instance of the temporary table, so the profile cannot match because we are on different objects, and we get the same problem, but on different non-shared instances of the temporary record.  Different literal values, such as those for Process Instance can be handled by FORCE_MATCHING, but not different tables.  This is a totally different SQL statement.
            SQL_ID 5gtxdqbx0d0c3
            --------------------
            INSERT INTO PS_CA_SUM_RC_TAO4 (…) SELECT

            FROM PS_CA_PR_SUMM A, PS_CA_SUM_TAO4 B , PS_CA_SUM_IN_USE C WHERE

            B.PROCESS_INSTANCE = 51377796 AND C.IN_USE_FLAG = 'Y'

            Plan hash value: 3552771247

            ---------------------------------------------------------------------------------------------------
            | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
            ---------------------------------------------------------------------------------------------------
            | 0 | INSERT STATEMENT | | | | 36361 (100)| |
            | 1 | LOAD TABLE CONVENTIONAL | | | | | |
            | 2 | HASH JOIN | | 1 | 430 | 36361 (3)| 00:07:17 |
            | 3 | TABLE ACCESS FULL | PS_CA_SUM_IN_USE | 1 | 85 | 14347 (1)| 00:02:53 |
            | 4 | NESTED LOOPS | | | | | |
            | 5 | NESTED LOOPS | | 1 | 345 | 22014 (3)| 00:04:25 |
            | 6 | TABLE ACCESS FULL | PS_CA_PR_SUMM | 5268K| 562M| 21539 (1)| 00:04:19 |
            | 7 | INDEX UNIQUE SCAN | PS_CA_SUM_TAO4 | 1 | | 0 (0)| |
            | 8 | TABLE ACCESS BY INDEX ROWID| PS_CA_SUM_TAO4 | 1 | 233 | 1 (0)| 00:00:01 |
            ---------------------------------------------------------------------------------------------------

            Note
            -----
            - SQL profile "coe_gn3n77gs6xj2a_3552771247" used for this statement
            Of course, the statement on instance 4 had a profile because it was added as a short term fix and then left in situ long term.  It worked fine until a process errored, left the non-shared instance of the temporary record allocated to that process instance, and so PeopleSoft allocated instance 5 on the next execution.
            So we could just create another profile using the coe_xfr_sql_profile.sql script
            SPO coe_xfr_sql_profile_5gtxdqbx0d0c3_3552771247.log;
            SET ECHO ON TERM ON LIN 2000 TRIMS ON NUMF 99999999999999999999;
            REM
            REM $Header: 215187.1 coe_xfr_sql_profile_5gtxdqbx0d0c3_3552771247.sql 11.4.1.4 2014/08/13 csierra $
            REM
            REM Copyright (c) 2000-2010, Oracle Corporation. All rights reserved.
            REM
            REM AUTHOR
            REM carlos.sierra@oracle.com
            REM
            REM SCRIPT
            REM coe_xfr_sql_profile_5gtxdqbx0d0c3_3552771247.sql
            REM
            REM DESCRIPTION
            REM This script is generated by coe_xfr_sql_profile.sql
            REM It contains the SQL*Plus commands to create a custom
            REM SQL Profile for SQL_ID 5gtxdqbx0d0c3 based on plan hash
            REM value 3552771247.
            REM The custom SQL Profile to be created by this script
            REM will affect plans for SQL commands with signature
            REM matching the one for SQL Text below.
            REM Review SQL Text and adjust accordingly.
            REM
            REM PARAMETERS
            REM None.
            REM
            REM EXAMPLE
            REM SQL> START coe_xfr_sql_profile_5gtxdqbx0d0c3_3552771247.sql;
            REM
            REM NOTES
            REM 1. Should be run as SYSTEM or SYSDBA.
            REM 2. User must have CREATE ANY SQL PROFILE privilege.
            REM 3. SOURCE and TARGET systems can be the same or similar.
            REM 4. To drop this custom SQL Profile after it has been created:
            REM EXEC DBMS_SQLTUNE.DROP_SQL_PROFILE('coe_5gtxdqbx0d0c3_3552771247');
            REM 5. Be aware that using DBMS_SQLTUNE requires a license
            REM for the Oracle Tuning Pack.
            REM
            WHENEVER SQLERROR EXIT SQL.SQLCODE;
            REM
            VAR signature NUMBER;
            REM
            DECLARE
            sql_txt CLOB;
            h SYS.SQLPROF_ATTR;
            BEGIN
            sql_txt := q'[
            INSERT INTO PS_CA_SUM_RC_TAO4 (PROCESS_INSTANCE, BUSINESS_UNIT, PROJECT_ID, ACTIVITY_ID, ANALYSIS_TYPE, RESOURCE_TYPE, RESOURCE_CATEGORY, RESOURCE_SUB_CAT, BI_DISTRIB_STATUS, GL_DISTRIB_STATUS, FOREIGN_CURRENCY, CONTRACT_CURRENCY, CONTRACT_NUM, CONTRACT_LINE_NUM, CA_FEE_STATUS, RESOURCE_QUANTITY, FOREIGN_AMOUNT_BSE, FOREIGN_AMOUNT_INC, FOREIGN_AMOUNT, CONTRACT_AMT_BSE, CONTRACT_AMT_INC, CONTRACT_AMT, MIN_TRANS_DT, MAX_TRANS_DT, CAND_MIN_TRANS_DT, CAND_MAX_TRANS_DT) SELECT B.PROCESS_INSTANCE, A.BUSINESS_UNIT, A.PROJECT_ID, A.ACTIVITY_ID, A.ANALYSIS_TYPE, A.RESOURCE_TYPE, A.RESOURCE_CATEGORY, A.RESOURCE_SUB_CAT, A.BI_DISTRIB_STATUS, A.GL_DISTRIB_STATUS,
            A.FOREIGN_CURRENCY, A.CONTRACT_CURRENCY, A.CONTRACT_NUM, A.CONTRACT_LINE_NUM, A.CA_FEE_STATUS, (A.RESOURCE_QUANTITY+B.RESOURCE_QUANTITY), A.FOREIGN_AMOUNT, B.FOREIGN_AMOUNT, (A.FOREIGN_AMOUNT+B.FOREIGN_AMOUNT), A.CONTRACT_AMT, B.CONTRACT_AMT, (A.CONTRACT_AMT+B.CONTRACT_AMT), A.MIN_TRANS_DT, A.MAX_TRANS_DT, B.CAND_MIN_TRANS_DT, B.CAND_MAX_TRANS_DT FROM PS_CA_PR_SUMM A, PS_CA_SUM_TAO4 B , PS_CA_SUM_IN_USE C WHERE B.BUSINESS_UNIT = C.BUSINESS_UNIT AND B.PROJECT_ID = C.PROJECT_ID AND B.ACTIVITY_ID = C.ACTIVITY_ID AND B.ANALYSIS_TYPE = C.ANALYSIS_TYPE AND B.RESOURCE_TYPE = C.RESOURCE_TYPE AND B.RESOURCE_CATEGORY = C.RESOURCE_CATEGORY AND B.RESOURCE_SUB_CAT =
            C.RESOURCE_SUB_CAT AND B.BI_DISTRIB_STATUS = C.BI_DISTRIB_STATUS AND B.GL_DISTRIB_STATUS = C.GL_DISTRIB_STATUS AND B.FOREIGN_CURRENCY = C.FOREIGN_CURRENCY AND B.CONTRACT_CURRENCY = C.CONTRACT_CURRENCY AND B.CONTRACT_NUM = C.CONTRACT_NUM AND B.CONTRACT_LINE_NUM = C.CONTRACT_LINE_NUM AND B.CA_FEE_STATUS = C.CA_FEE_STATUS AND A.BUSINESS_UNIT = B.BUSINESS_UNIT AND A.PROJECT_ID = B.PROJECT_ID AND A.ACTIVITY_ID = B.ACTIVITY_ID AND A.ANALYSIS_TYPE = B.ANALYSIS_TYPE AND A.RESOURCE_TYPE = B.RESOURCE_TYPE AND A.RESOURCE_CATEGORY = B.RESOURCE_CATEGORY AND A.RESOURCE_SUB_CAT = B.RESOURCE_SUB_CAT AND A.BI_DISTRIB_STATUS = B.BI_DISTRIB_STATUS AND A.GL_DISTRIB_STATUS =
            B.GL_DISTRIB_STATUS AND A.FOREIGN_CURRENCY = B.FOREIGN_CURRENCY AND A.CONTRACT_CURRENCY = B.CONTRACT_CURRENCY AND A.CONTRACT_NUM = B.CONTRACT_NUM AND A.CONTRACT_LINE_NUM = B.CONTRACT_LINE_NUM AND A.CA_FEE_STATUS = B.CA_FEE_STATUS AND B.PROCESS_INSTANCE = 51377796 AND C.IN_USE_FLAG = 'Y'
            ]';
            h := SYS.SQLPROF_ATTR(
            q'[BEGIN_OUTLINE_DATA]',
            q'[IGNORE_OPTIM_EMBEDDED_HINTS]',
            q'[OPTIMIZER_FEATURES_ENABLE('11.2.0.3')]',
            q'[DB_VERSION('11.2.0.3')]',
            q'[OPT_PARAM('_unnest_subquery' 'false')]',
            q'[OPT_PARAM('optimizer_dynamic_sampling' 4)]',
            q'[OPT_PARAM('_optimizer_cost_based_transformation' 'off')]',
            q'[ALL_ROWS]',
            q'[OUTLINE_LEAF(@"SEL$1")]',
            q'[OUTLINE_LEAF(@"INS$1")]',
            q'[FULL(@"INS$1" "PS_CA_SUM_RC_TAO4"@"INS$1")]',
            q'[FULL(@"SEL$1" "A"@"SEL$1")]',
            q'[INDEX(@"SEL$1" "B"@"SEL$1" ("PS_CA_SUM_TAO4"."PROCESS_INSTANCE" "PS_CA_SUM_TAO4"."BUSINESS_UNIT" "PS_CA_SUM_TAO4"."PROJECT_ID" "PS_CA_SUM_TAO4"."ACTIVITY_ID" "PS_CA_SUM_TAO4"."ANALYSIS_TYPE" "PS_CA_SUM_TAO4"."RESOURCE_TYPE" "PS_CA_SUM_TAO4"."RESOURCE_CATEGORY" "PS_CA_SUM_TAO4"."RESOURCE_SUB_CAT" "PS_CA_SUM_TAO4"."BI_DISTRIB_STATUS" "PS_CA_SUM_TAO4"."GL_DISTRIB_STATUS" "PS_CA_SUM_TAO4"."FOREIGN_CURRENCY" "PS_CA_SUM_TAO4"."CONTRACT_CURRENCY" "PS_CA_SUM_TAO4"."CONTRACT_NUM" ]',
            q'[ "PS_CA_SUM_TAO4"."CONTRACT_LINE_NUM" "PS_CA_SUM_TAO4"."CA_FEE_STATUS"))]',
            q'[FULL(@"SEL$1" "C"@"SEL$1")]',
            q'[LEADING(@"SEL$1" "A"@"SEL$1" "B"@"SEL$1" "C"@"SEL$1")]',
            q'[USE_NL(@"SEL$1" "B"@"SEL$1")]',
            q'[NLJ_BATCHING(@"SEL$1" "B"@"SEL$1")]',
            q'[USE_HASH(@"SEL$1" "C"@"SEL$1")]',
            q'[SWAP_JOIN_INPUTS(@"SEL$1" "C"@"SEL$1")]',
            q'[END_OUTLINE_DATA]');
            :signature := DBMS_SQLTUNE.SQLTEXT_TO_SIGNATURE(sql_txt);
            DBMS_SQLTUNE.IMPORT_SQL_PROFILE (
            sql_text => sql_txt,
            profile => h,
            name => 'coe_5gtxdqbx0d0c3_3552771247',
            description => 'coe 5gtxdqbx0d0c3 3552771247 '||:signature||'',
            category => 'DEFAULT',
            validate => TRUE,
            replace => TRUE,
            force_match => TRUE /* TRUE:FORCE (match even when different literals in SQL). FALSE:EXACT (similar to CURSOR_SHARING) */ );
            END;
            /
            WHENEVER SQLERROR CONTINUE
            SET ECHO OFF;
            PRINT signature
            PRO
            PRO ... manual custom SQL Profile has been created
            PRO
            SET TERM ON ECHO OFF LIN 80 TRIMS OFF NUMF "";
            SPO OFF;
            PRO
            PRO COE_XFR_SQL_PROFILE_5gtxdqbx0d0c3_3552771247 completed
            But then we must manually change the table and index names from 4 to 5.
            DECLARE
            sql_txt CLOB;
            h SYS.SQLPROF_ATTR;
            BEGIN
            sql_txt := q'[
            INSERT INTO PS_CA_SUM_RC_TAO5 (PROCESS_INSTANCE, BUSINESS_UNIT, PROJECT_ID, ACTIVITY_ID, ANALYSIS_TYPE, RESOURCE_TYPE, RESOURCE_CATEGORY, RESOURCE_SUB_CAT, BI_DISTRIB_STATUS, GL_DISTRIB_STATUS, FOREIGN_CURRENCY, CONTRACT_CURRENCY, CONTRACT_NUM, CONTRACT_LINE_NUM, CA_FEE_STATUS, RESOURCE_QUANTITY, FOREIGN_AMOUNT_BSE, FOREIGN_AMOUNT_INC, FOREIGN_AMOUNT, CONTRACT_AMT_BSE, CONTRACT_AMT_INC, CONTRACT_AMT, MIN_TRANS_DT, MAX_TRANS_DT, CAND_MIN_TRANS_DT, CAND_MAX_TRANS_DT) SELECT B.PROCESS_INSTANCE, A.BUSINESS_UNIT, A.PROJECT_ID, A.ACTIVITY_ID, A.ANALYSIS_TYPE, A.RESOURCE_TYPE, A.RESOURCE_CATEGORY, A.RESOURCE_SUB_CAT, A.BI_DISTRIB_STATUS, A.GL_DISTRIB_STATUS,
            A.FOREIGN_CURRENCY, A.CONTRACT_CURRENCY, A.CONTRACT_NUM, A.CONTRACT_LINE_NUM, A.CA_FEE_STATUS, (A.RESOURCE_QUANTITY+B.RESOURCE_QUANTITY), A.FOREIGN_AMOUNT, B.FOREIGN_AMOUNT, (A.FOREIGN_AMOUNT+B.FOREIGN_AMOUNT), A.CONTRACT_AMT, B.CONTRACT_AMT, (A.CONTRACT_AMT+B.CONTRACT_AMT), A.MIN_TRANS_DT, A.MAX_TRANS_DT, B.CAND_MIN_TRANS_DT, B.CAND_MAX_TRANS_DT FROM PS_CA_PR_SUMM A, PS_CA_SUM_TAO5 B , PS_CA_SUM_IN_USE C WHERE B.BUSINESS_UNIT = C.BUSINESS_UNIT AND B.PROJECT_ID = C.PROJECT_ID AND B.ACTIVITY_ID = C.ACTIVITY_ID AND B.ANALYSIS_TYPE = C.ANALYSIS_TYPE AND B.RESOURCE_TYPE = C.RESOURCE_TYPE AND B.RESOURCE_CATEGORY = C.RESOURCE_CATEGORY AND B.RESOURCE_SUB_CAT =
            C.RESOURCE_SUB_CAT AND B.BI_DISTRIB_STATUS = C.BI_DISTRIB_STATUS AND B.GL_DISTRIB_STATUS = C.GL_DISTRIB_STATUS AND B.FOREIGN_CURRENCY = C.FOREIGN_CURRENCY AND B.CONTRACT_CURRENCY = C.CONTRACT_CURRENCY AND B.CONTRACT_NUM = C.CONTRACT_NUM AND B.CONTRACT_LINE_NUM = C.CONTRACT_LINE_NUM AND B.CA_FEE_STATUS = C.CA_FEE_STATUS AND A.BUSINESS_UNIT = B.BUSINESS_UNIT AND A.PROJECT_ID = B.PROJECT_ID AND A.ACTIVITY_ID = B.ACTIVITY_ID AND A.ANALYSIS_TYPE = B.ANALYSIS_TYPE AND A.RESOURCE_TYPE = B.RESOURCE_TYPE AND A.RESOURCE_CATEGORY = B.RESOURCE_CATEGORY AND A.RESOURCE_SUB_CAT = B.RESOURCE_SUB_CAT AND A.BI_DISTRIB_STATUS = B.BI_DISTRIB_STATUS AND A.GL_DISTRIB_STATUS =
            B.GL_DISTRIB_STATUS AND A.FOREIGN_CURRENCY = B.FOREIGN_CURRENCY AND A.CONTRACT_CURRENCY = B.CONTRACT_CURRENCY AND A.CONTRACT_NUM = B.CONTRACT_NUM AND A.CONTRACT_LINE_NUM = B.CONTRACT_LINE_NUM AND A.CA_FEE_STATUS = B.CA_FEE_STATUS AND B.PROCESS_INSTANCE = 51377796 AND C.IN_USE_FLAG = 'Y'
            ]';
            h := SYS.SQLPROF_ATTR(
            q'[BEGIN_OUTLINE_DATA]',
            q'[IGNORE_OPTIM_EMBEDDED_HINTS]',
            q'[OPTIMIZER_FEATURES_ENABLE('11.2.0.3')]',
            q'[DB_VERSION('11.2.0.3')]',
            q'[OPT_PARAM('_unnest_subquery' 'false')]',
            q'[OPT_PARAM('optimizer_dynamic_sampling' 4)]',
            q'[OPT_PARAM('_optimizer_cost_based_transformation' 'off')]',
            q'[ALL_ROWS]',
            q'[OUTLINE_LEAF(@"SEL$1")]',
            q'[OUTLINE_LEAF(@"INS$1")]',
            q'[FULL(@"INS$1" "PS_CA_SUM_RC_TAO5"@"INS$1")]',
            q'[FULL(@"SEL$1" "A"@"SEL$1")]',
            q'[INDEX(@"SEL$1" "B"@"SEL$1" ("PS_CA_SUM_TAO5"."PROCESS_INSTANCE" "PS_CA_SUM_TAO5"."BUSINESS_UNIT" "PS_CA_SUM_TAO5"."PROJECT_ID" "PS_CA_SUM_TAO5"."ACTIVITY_ID" "PS_CA_SUM_TAO5"."ANALYSIS_TYPE" "PS_CA_SUM_TAO5"."RESOURCE_TYPE" "PS_CA_SUM_TAO5"."RESOURCE_CATEGORY" "PS_CA_SUM_TAO5"."RESOURCE_SUB_CAT" "PS_CA_SUM_TAO5"."BI_DISTRIB_STATUS" "PS_CA_SUM_TAO5"."GL_DISTRIB_STATUS" "PS_CA_SUM_TAO5"."FOREIGN_CURRENCY" "PS_CA_SUM_TAO5"."CONTRACT_CURRENCY" "PS_CA_SUM_TAO5"."CONTRACT_NUM" ]',
            q'[ "PS_CA_SUM_TAO5"."CONTRACT_LINE_NUM" "PS_CA_SUM_TAO5"."CA_FEE_STATUS"))]',
            q'[FULL(@"SEL$1" "C"@"SEL$1")]',
            q'[LEADING(@"SEL$1" "A"@"SEL$1" "B"@"SEL$1" "C"@"SEL$1")]',
            q'[USE_NL(@"SEL$1" "B"@"SEL$1")]',
            q'[NLJ_BATCHING(@"SEL$1" "B"@"SEL$1")]',
            q'[USE_HASH(@"SEL$1" "C"@"SEL$1")]',
            q'[SWAP_JOIN_INPUTS(@"SEL$1" "C"@"SEL$1")]',
            q'[END_OUTLINE_DATA]');
            :signature := DBMS_SQLTUNE.SQLTEXT_TO_SIGNATURE(sql_txt);
            DBMS_SQLTUNE.IMPORT_SQL_PROFILE (
            sql_text => sql_txt,
            profile => h,
            name => 'coe_5gtxdqbx0d0c3_3552771247',
            description => 'coe 5gtxdqbx0d0c3 3552771247 '||:signature||'',
            category => 'DEFAULT',
            validate => TRUE,
            replace => TRUE,
            force_match => TRUE /* TRUE:FORCE (match even when different literals in SQL). FALSE:EXACT (similar to CURSOR_SHARING) */ );
            END;
            /
            Or to take Arms against a Sea of statements, The profile has advantage that it can be applied quickly without a code change.  It is the perfect tool for the DBA with a production performance problem. However, there are some other considerations.
            • If applying to statement that references a PS temp record then we need to apply the profile to all instances of the record (both non-shared instances and the shared instance).
            • We were lucky that we referenced instance 5 of two temporary records. However, you could get a situation where a statement references different instances of different temporary records.  So perhaps instance 5 of one table and instance 6 of another.  In which case, you might also get instance 6 of the first table and instance 5 of the other.  A SQL profile could be needed for each permutation.
            • Bear in mind also that some areas of PeopleSoft use dynamically generated SQL.  So you get similar SQL statements which are sufficiently different for the profile not to match.  
            • Any changes to the expansion of Application Engine and PeopleCode MetaSQL on upgrading PeopleTools, or potentially even patching, will also prevent matching.
            • There is also the challenge of dealing with code changes as the system is upgraded, patched and customised.  A small code change, perhaps just an extra field in the select clause, can result in a performance regression because the profile stops matching. Of course, this challenge is not limited to PeopleSoft systems! 
            Profiles are likely to be effective if there are no PeopleSoft temporary records present.  So you can generally use them in COBOL and SQR processes and the on-line application (other than in on-line Application Engine processes). Aye, there's the rub,I would use a profile (or a set of profiles) as a short-term temporary fix that is easier to introduce into production, and then add hints to the source code and so fix all instances of the code, not just the ones that have been profiled. Of course, that does entail a code change, and everything that goes with that.  One strong argument against making code change is that you have to change the code again to remove or change the hint if it becomes unnecessary at some time in future after a significant change, such as an Oracle upgrade.  However, on balance, I think it is better than the scenario where the profile stops working one day without warning.The rest is silence.Unless you add a comment.©David Kurtz, Go-Faster Consultancy Ltd.

            Introducing the Analytic Keep Clause for Effective-Dated/Sequence Queries in PeopleSoft

            Wed, 2014-07-09 12:46
            Those of us who work with PeopleSoft, and especially the HCM product, are all too familiar with the concept of effect-dated data, and the need to find data that was effective at a particular date.  PeopleSoft products have always made extensive use of correlated sub-queries to determine the required rows from an effective-dated record.

            The JOB record is a the heart of HCM. It is both effective-dated and effective sequenced. I will use it for the demonstrations in this article. I am going to suggest an alternative, although Oracle-specific, SQL construction.

             Let's start by looking at the job data for an employee in the demo database. Employee KF0018 has 17 rows of data two concurrent jobs.  The question I am going to ask is "What was the annual salary for this employee on 11 February 1995?".  Therefore, I am interested in the rows marked below with the asterisks. 
            column annual_rt format 999,999
            SELECT emplid, empl_rcd, effdt, effseq, action, deptid, currency_cd, annual_rt
            FROM ps_job j
            WHERE j.emplid = 'KF0018'
            ORDER BY 1,2,3,4
            /

            EMPLID        EMPL_RCD EFFDT         EFFSEQ ACT DEPTID     CUR ANNUAL_RT
            ----------- ---------- --------- ---------- --- ---------- --- ---------
            KF0018 0 12-JUN-83 0 HIR 13000 FRF 120,000
            KF0018 0 01-JAN-84 0 PAY 13000 FRF 123,600
            KF0018 0 01-JAN-85 0 PAY 13000 FRF 127,308
            KF0018 0 01-JAN-86 0 PAY 13000 FRF 131,764
            KF0018 0 01-JAN-87 0 PAY 13000 FRF 136,376
            KF0018 0 01-JAN-88 0 PAY 13000 FRF 140,467
            KF0018 0 01-JAN-89 0 PAY 13000 FRF 147,490
            KF0018 0 22-JAN-95 0 PRO 13000 FRF 147,490
            KF0018 0 22-JAN-95 1 PAY 13000 FRF 294,239 *
            KF0018 0 22-JAN-96 0 PAY 13000 FRF 318,575
            KF0018 0 01-JAN-98 0 PAY 13000 FRF 346,156
            KF0018 0 01-JAN-00 0 DTA 13000 FRF 346,156
            KF0018 0 01-JAN-02 0 PAY 13000 EUR 52,771
            KF0018 1 01-NOV-89 0 ASG 21300 GBP 22,440
            KF0018 1 31-DEC-93 0 ASC 21300 GBP 22,440
            KF0018 1 01-JAN-94 0 ASG 12000 GBP 22,440 *
            KF0018 1 31-DEC-95 0 ASC 10000 GBP 22,440

            I will set statistics level to ALL so I can obtain detailed information about how the SQL statements execute:
            ALTER SESSION SET statistics_level = ALL;

            I extracted the execution plans and execution statistics with the following command
            select * from table(dbms_xplan.display_cursor(null,null,'IOSTATS')) 
            Typical PeopleSoft Platform Agnostic ConstructionThis is the usual way to construct the query in PeopleSoft. It is also valid on all databases platforms supported by PeopleSoft, not just Oracle. 
            SELECT  emplid, empl_rcd, effdt, effseq, action, deptid, currency_cd, annual_rt
            FROM ps_job j
            WHERE j.effdt = (
            SELECT MAX (j1.effdt) FROM ps_job j1
            WHERE j1.emplid = j.emplid
            AND j1.empl_rcd = j.empl_rcd
            AND j1.effdt <= TO_DATE('19950211','YYYYMMDD'))
            AND j.effseq = (
            SELECT MAX (j2.effseq) FROM ps_job j2
            WHERE j2.emplid = j.emplid
            AND j2.empl_rcd = j.empl_rcd
            AND j2.effdt = j.effdt)
            AND j.emplid = 'KF0018'
            ORDER BY 1,2,3,4
            /

            EMPLID        EMPL_RCD EFFDT         EFFSEQ ACT DEPTID     CUR ANNUAL_RT
            ----------- ---------- --------- ---------- --- ---------- --- ---------
            KF0018 0 22-JAN-95 1 PAY 13000 FRF 294,239
            KF0018 1 01-JAN-94 0 ASG 12000 GBP 22,440

            This required three access of indexes on the PS_JOB table, and two accesses of the table, using 26 consistent reads.
            Plan hash value: 2299825310
            ----------------------------------------------------------------------------------------------------------------
            | Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers | Reads |
            ----------------------------------------------------------------------------------------------------------------
            | 0 | SELECT STATEMENT | | 1 | | 2 |00:00:00.01 | 26 | 2 |
            | 1 | SORT ORDER BY | | 1 | 1 | 2 |00:00:00.01 | 26 | 2 |
            | 2 | NESTED LOOPS | | 1 | 1 | 2 |00:00:00.01 | 26 | 2 |
            | 3 | NESTED LOOPS | | 1 | 1 | 3 |00:00:00.01 | 21 | 2 |
            | 4 | VIEW | VW_SQ_1 | 1 | 1 | 2 |00:00:00.01 | 14 | 2 |
            |* 5 | FILTER | | 1 | | 2 |00:00:00.01 | 14 | 2 |
            | 6 | HASH GROUP BY | | 1 | 1 | 2 |00:00:00.01 | 14 | 2 |
            | 7 | TABLE ACCESS BY INDEX ROWID| PS_JOB | 1 | 1 | 12 |00:00:00.01 | 14 | 2 |
            |* 8 | INDEX RANGE SCAN | PS_JOB | 1 | 1 | 12 |00:00:00.01 | 2 | 2 |
            | 9 | TABLE ACCESS BY INDEX ROWID | PS_JOB | 2 | 1 | 3 |00:00:00.01 | 7 | 0 |
            |* 10 | INDEX RANGE SCAN | PSAJOB | 2 | 1 | 3 |00:00:00.01 | 4 | 0 |
            |* 11 | VIEW PUSHED PREDICATE | VW_SQ_2 | 3 | 1 | 2 |00:00:00.01 | 5 | 0 |
            |* 12 | FILTER | | 3 | | 3 |00:00:00.01 | 5 | 0 |
            | 13 | SORT AGGREGATE | | 3 | 1 | 3 |00:00:00.01 | 5 | 0 |
            |* 14 | FILTER | | 3 | | 5 |00:00:00.01 | 5 | 0 |
            |* 15 | INDEX RANGE SCAN | PSAJOB | 3 | 1 | 5 |00:00:00.01 | 5 | 0 |
            ----------------------------------------------------------------------------------------------------------------

            Predicate Information (identified by operation id):
            ---------------------------------------------------

            5 - filter("J1"."EMPLID"='KF0018')
            8 - access("J1"."EMPLID"='KF0018' AND "J1"."SYS_NC00164$">=HEXTORAW('883CFDF4FEF8FEFAFF') )
            filter(SYS_OP_UNDESCEND("J1"."SYS_NC00164$")<=TO_DATE(' 1995-02-11 00:00:00', 'syyyy-mm-dd
            hh24:mi:ss'))
            10 - access("J"."EMPLID"='KF0018' AND "ITEM_2"="J"."EMPL_RCD" AND
            "J"."SYS_NC00164$"=SYS_OP_DESCEND("MAX(J1.EFFDT)"))
            filter(SYS_OP_UNDESCEND("J"."SYS_NC00164$")="MAX(J1.EFFDT)")
            11 - filter(SYS_OP_UNDESCEND("J"."SYS_NC00165$")="MAX(J2.EFFSEQ)")
            12 - filter(COUNT(*)>0)
            14 - filter('KF0018'="J"."EMPLID")
            15 - access("J2"."EMPLID"='KF0018' AND "J2"."EMPL_RCD"="J"."EMPL_RCD" AND
            "J2"."SYS_NC00164$"=SYS_OP_DESCEND(SYS_OP_UNDESCEND("J"."SYS_NC00164$")))
            filter(SYS_OP_UNDESCEND("J2"."SYS_NC00164$")=SYS_OP_UNDESCEND("J"."SYS_NC00164$"))

            This construction is also the reason you are required to set
            _UNNEST_SUBQUERY=FALSE
            on all PeopleSoft systems
            Analytic Function and In-LineView/Sub-query FactorI have seen people use a combination of analytic functions and in-line views to avoid having to use the correlated sub-query construction. This has been possible since Oracle 9i.
            WITH X AS (
            SELECT emplid, empl_rcd, effdt, effseq, action, deptid, currency_cd, annual_rt
            , ROW_NUMBER() OVER (PARTITION BY emplid, empl_rcd 
            ORDER BY effdt DESC, effseq DESC) myrowseq
            FROM ps_job j
            WHERE j.effdt <= TO_DATE('19950211','YYYYMMDD')
            AND j.emplid = 'KF0018'
            )
            SELECT emplid, empl_rcd, effdt, effseq, action, deptid, currency_cd, annual_rt
            FROM x
            WHERE myrowseq = 1
            ORDER BY 1,2,3,4
            /

            EMPLID        EMPL_RCD EFFDT         EFFSEQ ACT DEPTID     CUR ANNUAL_RT
            ----------- ---------- --------- ---------- --- ---------- --- ---------
            KF0018 0 22-JAN-95 1 PAY 13000 FRF 294,239
            KF0018 1 01-JAN-94 0 ASG 12000 GBP 22,440

            We get the same result, but now the index is scanned just once and we only need 14 consistent reads, so it produces a significant improvement. However, it still includes a sort operation in addition to the window function. We have to create a sequence number field in the in-line view and filter by that in the final query.
            Plan hash value: 1316906785
            ---------------------------------------------------------------------------------------------------
            | Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers |
            ---------------------------------------------------------------------------------------------------
            | 0 | SELECT STATEMENT | | 1 | | 2 |00:00:00.01 | 14 |
            | 1 | SORT ORDER BY | | 1 | 1 | 2 |00:00:00.01 | 14 |
            |* 2 | VIEW | | 1 | 1 | 2 |00:00:00.01 | 14 |
            |* 3 | WINDOW NOSORT | | 1 | 1 | 12 |00:00:00.01 | 14 |
            | 4 | TABLE ACCESS BY INDEX ROWID| PS_JOB | 1 | 1 | 12 |00:00:00.01 | 14 |
            |* 5 | INDEX RANGE SCAN | PSAJOB | 1 | 1 | 12 |00:00:00.01 | 2 |
            ---------------------------------------------------------------------------------------------------

            Predicate Information (identified by operation id):
            ---------------------------------------------------

            2 - filter("MYROWSEQ"=1)
            3 - filter(ROW_NUMBER() OVER ( PARTITION BY "EMPLID","EMPL_RCD" ORDER BY
            "J"."SYS_NC00164$","J"."SYS_NC00165$")<=1)
            5 - access("J"."EMPLID"='KF0018' AND "J"."SYS_NC00164$">=HEXTORAW('883CFDF4FEF8FEFAFF')
            )
            filter(SYS_OP_UNDESCEND("J"."SYS_NC00164$")<=TO_DATE(' 1995-02-11 00:00:00',
            'syyyy-mm-dd hh24:mi:ss'))

            Analytic Function Keep Clause This form of the analytic functions is documented for the first time in 12c, but is available in 10g (my thanks to Tony Hasler for introducing me to it). It works by effectively keeping a running maximum value of the columns in the order by clause within in group.
            SELECT emplid, empl_rcd
            , MAX(effdt) KEEP (DENSE_RANK LAST ORDER BY effdt, effseq) AS effdt
            , MAX(effseq) KEEP (DENSE_RANK LAST ORDER BY effdt, effseq) AS effseq
            , MAX(action) KEEP (DENSE_RANK LAST ORDER BY effdt, effseq) AS action
            , MAX(deptid) KEEP (DENSE_RANK LAST ORDER BY effdt, effseq) AS deptid
            , MAX(currency_cd) KEEP (DENSE_RANK LAST ORDER BY effdt, effseq) AS currency_cd
            , MAX(annual_rt) KEEP (DENSE_RANK LAST ORDER BY effdt, effseq) AS annual_rt
            FROM ps_job j
            WHERE j.effdt <= TO_DATE('19950211','YYYYMMDD')
            AND j.emplid = 'KF0018'
            GROUP BY emplid, empl_rcd
            /

            EMPLID        EMPL_RCD EFFDT         EFFSEQ ACT DEPTID     CUR ANNUAL_RT
            ----------- ---------- --------- ---------- --- ---------- --- ---------
            KF0018 0 22-JAN-95 1 PAY 13000 FRF 294,239
            KF0018 1 01-JAN-94 0 ASG 12000 GBP 22,440

            Although this construction uses an additional consistent read, it has the advantage of not using either an inline view or a window function and does not sort the data.
            Plan hash value: 1550496807
            -------------------------------------------------------------------------------------------------
            | Id | Operation | Name | Starts | E-Rows | A-Rows | A-Time | Buffers |
            -------------------------------------------------------------------------------------------------
            | 0 | SELECT STATEMENT | | 1 | | 2 |00:00:00.01 | 15 |
            | 1 | SORT GROUP BY NOSORT | | 1 | 1 | 2 |00:00:00.01 | 15 |
            | 2 | TABLE ACCESS BY INDEX ROWID| PS_JOB | 1 | 1 | 12 |00:00:00.01 | 15 |
            |* 3 | INDEX RANGE SCAN | PS_JOB | 1 | 1 | 12 |00:00:00.01 | 3 |
            -------------------------------------------------------------------------------------------------

            Predicate Information (identified by operation id):
            ---------------------------------------------------

            3 - access("J"."EMPLID"='KF0018' AND "J"."SYS_NC00164$">=HEXTORAW('883CFDF3FEF8FEFAFF'
            ) )
            filter(SYS_OP_UNDESCEND("J"."SYS_NC00164$")<=TO_DATE(' 1995-02-12 00:00:00',
            'syyyy-mm-dd hh24:mi:ss'))

            I think this construction could be useful in PeopleSoft.  At first glance the SQL appears more complicated, but it in this example it removed two correlated sub-queries. 
            Using Analytic Functions in PS/QueryOf course you can code it anywhere where you can simply enter SQL as text.  However, it also has the advantage over the other analytic function construction that it can be coded in the PS/Query tool.  The analytic functions in the select caluse should be created in PS/Query expressions with the aggregate expression checkbox ticked.
            Analytic 'Keep' function in PS/Query Aggregate ExpressionAnalytic Function in Aggregated Expression in Windows Client version of PS/Query  The analytic functions can be selected in the PS/Query, and their lengths and titles can be tidied up.
            Analytic PS/QueryPS/Query with Analytic 'Keep' Functions
            This is the resulting SQL which is the same as before (with row level security added by PS/Query) and produces the same results.
            SELECT A.EMPLID, A.EMPL_RCD, MAX(effdt) KEEP (DENSE_RANK LAST ORDER BY effdt, effseq)
            , MAX(effseq) KEEP (DENSE_RANK LAST ORDER BY effdt, effseq), MAX(action) KEEP (DENSE_RANK LAST ORDER BY effdt, effseq), MAX(deptid) KEEP (DENSE_RANK LAST ORDER BY effdt, effseq), MAX(currency_cd) KEEP (DENSE_RANK LAST ORDER BY effdt, effseq), MAX(annual_rt) KEEP (DENSE_RANK LAST ORDER BY effdt, effseq)
            FROM PS_JOB A, PS_EMPLMT_SRCH_QRY A1
            WHERE ( A.EMPLID = A1.EMPLID
            AND A.EMPL_RCD = A1.EMPL_RCD
            AND A1.OPRID = 'PS'
            AND ( A.EFFDT <= TO_DATE('1995-02-11','YYYY-MM-DD')
            AND A.EMPLID = 'KF0018' ) )
            GROUP BY A.EMPLID, A.EMPL_RCD
            ©David Kurtz, Go-Faster Consultancy Ltd.