Tuesday, February 20, 2024

What PS/Query is that?

Sometimes, performance analysis will turn up a problem SQL query that is probably a PS/Query. However, I need to know which PS/Query it is should I wish to alter it or talk to the user who wrote it. 

Is it a PS/Query?

It is quite easy to spot SQL queries that are generated from queries defined in the PS/Query tool. These are typical characteristics:

  • Single character row source aliases (eg. A, B, D) 
  • The same row source with a suffix 1 (eg. D1) for query security records.
  • Effective date/sequence subqueries are always correlated back to the same table.
  • Order by column position number rather than column names or aliases.
Sometimes, you may find SQL that looks like a PS/Query coming from other parts of PeopleSoft because a developer has copied the text of a PS/Query, usually into an Application Engine step.
SELECT A.EMPLID, A.ATTENDANCE, A.COURSE, B.DESCR, D.NAME, A.SESSION_NBR,
TO_CHAR(A.STATUS_DT,'YYYY-MM-DD'),B.COURSE
FROM PS_TRAINING A, PS_COURSE_TBL B, PS_PERSONAL_DTA_VW D, PS_PERS_SRCH_QRY D1
WHERE D.EMPLID = D1.EMPLID
AND D1.ROWSECCLASS = 'HCDPALL'
AND ( A.COURSE = :1
AND A.ATTENDANCE IN ('S','W')
AND A.COURSE = B.COURSE
AND A.EMPLID = D.EMPLID )

The text of a PS/Query is not stored in the database.  Instead, as with other objects in PeopleSoft, it is held as various rows in PeopleTools tables.  The PSQRY% tables are used to generate the SQL on demand.  We can query these tables to identify the query.  

PSQRYRECORD holds a row for every record referenced in the query (not including effective date/sequence subqueries).  My usual tactic is to write a SQL query on PSQRYRECORD, like the one below, that looks for PS/Queries that reference these tables with these table aliases (see PeopleSoft for the Oracle DBA, Chapter 11).  
REM findqry.sql
REM (c)Go-Faster Consultancy 2012

SELECT a.oprid, a.qryname
FROM   psqryrecord a
,      psqryrecord b
,      psqryrecord d
WHERE  a.oprid = b.oprid
AND    a.qryname = b.qryname
AND    a.oprid = d.oprid
AND    a.qryname = d.qryname
AND    a.corrname = 'A'
AND    a.recname = 'TRAINING'
AND    b.corrname = 'B'
AND    b.recname = 'COURSE_TBL'
AND    d.corrname = 'D'
AND    d.recname = 'PERSONAL_DTA_VW'
/
The example PS/Query above is TRN003__COURSE_WAITING_LIST from the HCM demo database.  However, my query on PSQRYRECORD found another PS/Queries with the same 3 records using the same row source aliases.  It is worth looking at queries on the same tables as they often suffer from the same problems, and you might want to make the same fix.  
Another source of results for this query (though not this time) can be when users copy a public PS/Query to a private one so they can alter it in isolation.
OPRID                          QRYNAME
------------------------------ ------------------------------
                               TRN002__SESSION_ROSTER
                               TRN003__COURSE_WAITING_LIST

Writing the query on PSQRYRECORD to find queries, which always is slightly different each time, is quite boring.  So I have written a script that will dynamically generate the SQL to identify a PS/Query.

Start with a SQL_ID

A SQL tuning activity will usually identify the SQL_ID and plan hash value of a statement.  If you are lucky, AWR will have captured the text and execution plan.  If not, you may have to try looking for a different SQL_ID that produces the same execution plan.  From the statement text, it is easy to see whether it might be a PS/Query.  
In this example, I have cut the SQL statement and execution plan back to show just the tables and indexes referenced.
SQL_ID c3h6vf2w5fxgp
--------------------
SELECT …
FROM PSTREELEAF B, PSTREENODE C, PS_OPER_UNIT_TBL A, PS_PRODUCT_TBL G 
…
UNION SELECT …
FROM PSTREENODE D,PS_TREE_NODE_TBL E, PSTREELEAF F 
…

--------------------------------------------------------------------------------------------------------------------------
|   Id  | Operation                                   | Name             | Rows  | Bytes |TempSpc| Cost (%CPU)| Time     |
--------------------------------------------------------------------------------------------------------------------------
|  *  7 |        INDEX STORAGE FAST FULL SCAN         | PSBPSTREELEAF    |   426K|    19M|       |  1178   (1)| 00:00:01 |
|    10 |          TABLE ACCESS BY INDEX ROWID BATCHED| PS_PRODUCT_TBL   |     1 |    41 |       |     3   (0)| 00:00:01 |
|  * 11 |           INDEX RANGE SCAN                  | PS_PRODUCT_TBL   |     1 |       |       |     2   (0)| 00:00:01 |
|  * 14 |              INDEX RANGE SCAN (MIN/MAX)     | PS_PRODUCT_TBL   |     1 |    21 |       |     2   (0)| 00:00:01 |
|  * 15 |       TABLE ACCESS STORAGE FULL             | PSTREENODE       |   135K|  5709K|       |   663   (1)| 00:00:01 |
|  * 17 |       INDEX STORAGE FAST FULL SCAN          | PS_OPER_UNIT_TBL |  1791 | 35820 |       |     4   (0)| 00:00:01 |
|  * 20 |       INDEX RANGE SCAN (MIN/MAX)            | PS_PSTREENODE    |     1 |    33 |       |     3   (0)| 00:00:01 |
|  * 23 |       INDEX RANGE SCAN (MIN/MAX)            | PSAPSTREELEAF    |     1 |    32 |       |     3   (0)| 00:00:01 |
|  * 26 |       INDEX RANGE SCAN (MIN/MAX)            | PS_OPER_UNIT_TBL |     1 |    20 |       |     2   (0)| 00:00:01 |
|    33 |          TABLE ACCESS INMEMORY FULL         | PS_TREE_NODE_TBL | 35897 |  1647K|       |     6   (0)| 00:00:01 |
|  * 35 |          TABLE ACCESS STORAGE FULL          | PSTREENODE       |   167K|  9670K|       |   663   (1)| 00:00:01 |
|- * 36 |       INDEX RANGE SCAN                      | PS_PSTREELEAF    |     1 |    39 |       |  1267   (1)| 00:00:01 |
|    37 |      INDEX STORAGE FAST FULL SCAN           | PS_PSTREELEAF    |   480K|    17M|       |  1267   (1)| 00:00:01 |
|  * 40 |       INDEX RANGE SCAN (MIN/MAX)            | PS_PSTREENODE    |     1 |    33 |       |     3   (0)| 00:00:01 |
|  * 43 |       INDEX RANGE SCAN (MIN/MAX)            | PS_TREE_NODE_TBL |     1 |    28 |       |     2   (0)| 00:00:01 |
--------------------------------------------------------------------------------------------------------------------------

Query Block Name / Object Alias (identified by operation id):
-------------------------------------------------------------

…
   7 - SEL$1 / B@SEL$1
  10 - SEL$1 / G@SEL$1
  11 - SEL$1 / G@SEL$1
…
  15 - SEL$1 / C@SEL$1
  17 - SEL$1 / A@SEL$1
…
  33 - SEL$6 / E@SEL$6
  35 - SEL$6 / D@SEL$6
  36 - SEL$6 / F@SEL$6
  37 - SEL$6 / F@SEL$6
…

I use this query on DBA_HIST_SQL_PLAN to extract the tables that have single-character row source aliases that correspond to PeopleSoft records, and put them into PLAN_TABLE. I use this table because it is delivered by Oracle as a global temporary table, so it is always there and I can make use of it even if I only have read-only access.

INSERT INTO plan_table (object_name, object_alias) 
with p as ( --plan lines with single letter aliases
SELECT DISTINCT object_owner, object_type, object_name, regexp_substr(object_alias,'[[:alpha:]]',2,1) object_alias
from dba_hist_sql_plan p
, ps.psdbowner d
where p.sql_id = '&&sql_id' --put SQL ID here--
and p.object_name IS NOT NULL
and p.object_owner = d.ownerid
and regexp_like(object_alias,'"[[:alpha:]]"') --single character aliases
), r as ( --PeopleSoft table records and the table name
select r.recname, DECODE(r.sqltablename,' ','PS_'||r.recname,r.sqltablename) sqltablename
from psrecdefn r
where r.rectype = 0 --PeopleSoft table records
)
select r.recname, object_alias --referenced table
from p, r
where p.object_type like 'TABLE%'
and p.object_name = r.sqltablename
union --a query plan may reference an index and not the table
select r.recname, object_alias --table for referenced index
from p, r
, all_indexes i
where p.object_type like 'INDEX%'
and i.index_name = p.object_name
and i.owner = p.object_owner
and i.table_name = r.sqltablename
order by 2,1
/
I now have a list of records and row source aliases aliases
RECNAME         O
--------------- -
OPER_UNIT_TBL   A
PSTREELEAF      B
PSTREENODE      C
PSTREENODE      D
TREE_NODE_TBL   E
PSTREELEAF      F
PRODUCT_TBL     G

Next, I can run this anonymous PL/SQL block to dynamically build the SQL query on PSQRYRECORD (one reference for every table) and execute it to find the matching PS/Queries

DECLARE 
  l_sep1 VARCHAR2(20);
  l_sep2 VARCHAR2(20);
  l_counter INTEGER := 0;
  l_sql CLOB := 'SELECT r1.oprid, r1.qryname';
  l_where CLOB;
  
  TYPE t_query IS RECORD (oprid VARCHAR2(30), qryname VARCHAR2(30));
  TYPE a_query IS TABLE OF t_query INDEX BY PLS_INTEGER;
  l_query a_query;
BEGIN
  FOR i IN(
    SELECT *
    FROM plan_table
    ORDER BY object_alias
  ) LOOP
    l_counter := l_counter + 1;
    dbms_output.put_line(i.object_alias||':'||i.object_name);
    IF l_counter = 1 THEN
      l_sep1 := ' FROM ';
      l_sep2 := ' WHERE ';
    ELSE
      l_sep1 := ' ,';
      l_sep2 := ' AND ';
      l_where := l_where||' AND r1.oprid = r'||l_counter||'.oprid AND r1.qryname = r'||l_counter||'.qryname';
    END IF;
    l_sql := l_sql||l_sep1||'psqryrecord r'||l_counter;
    l_where := l_where||l_sep2||'r'||l_counter||'.corrname = '''||i.object_alias||''' AND r'||l_counter||'.recname = '''||i.object_name||'''';
  END LOOP;
  l_sql := l_sql||l_where||' ORDER BY 1,2';
  dbms_output.put_line(l_sql);

  EXECUTE IMMEDIATE l_sql BULK COLLECT INTO l_query;

  FOR indx IN 1 .. l_query.COUNT
  LOOP
    DBMS_OUTPUT.put_line (indx||':'||l_query(indx).oprid||'.'||l_query(indx).qryname);
  END LOOP;
END;
/

The seven records found in my execution plan become a query of PSQRYRECORD 7 times, one for each record, joined on operator ID and query name.

SELECT r1.oprid, r1.qryname 
FROM psqryrecord r1 ,psqryrecord r2 ,psqryrecord r3 ,psqryrecord r4 ,psqryrecord r5 ,psqryrecord r6 ,psqryrecord r7 
WHERE r1.corrname = 'A' AND r1.recname = 'OPER_UNIT_TBL'
AND r1.oprid = r2.oprid AND r1.qryname = r2.qryname AND r2.corrname = 'B' AND r2.recname = 'PSTREELEAF' 
AND r1.oprid = r3.oprid AND r1.qryname = r3.qryname AND r3.corrname = 'C' AND r3.recname = 'PSTREENODE' 
AND r1.oprid = r4.oprid AND r1.qryname = r4.qryname AND r4.corrname = 'D' AND r4.recname = 'PSTREENODE' 
AND r1.oprid = r5.oprid AND r1.qryname = r5.qryname AND r5.corrname = 'E' AND r5.recname = 'TREE_NODE_TBL' 
AND r1.oprid = r6.oprid AND r1.qryname = r6.qryname AND r6.corrname = 'F' AND r6.recname = 'PSTREELEAF' 
AND r1.oprid = r7.oprid AND r1.qryname = r7.qryname AND r7.corrname = 'G' AND r7.recname = 'PRODUCT_TBL' 
ORDER BY 1,2
The query finds several queries. I can look at the public PS/Queries in the Query Manager tool.  I can also see which users' private queries exist.
NB. You can only open public queries (where OPRID is a single space) or your own private queries.  In the Query Manager, you cannot see a private query owned by another user.
…
3: .PS_TREE_PRODUCT
4: .QUERY_PRODUCT_TREE
5: .RM_TREE_PRODUCT
6:XXXXXX.PS_TREE_PRODUCT_XX
…
The new findqry.sql script is available on Github.

Thursday, January 25, 2024

Reducing the Operating System Priority of PeopleSoft Processes

PeopleSoft for the Oracle DBA

I wrote about controlling the operating system priority of processes in PeopleSoft Tuxedo domains in Chapters 13 of 14 of PeopleSoft for the Oracle DBA, but I think it is worth a note here.

On Linux and Unix systems, the nice command can be used to lower the operating system scheduling priority of a process (or a privileged can increase the priority). When a server has no free CPU, processes with a lower priority get less time on the CPU. However, when there is free CPU available, the scheduling priority does not affect the amount of CPU that the process can utilise. 

On Unix, the priority of a Tuxedo server process can be adjusted using the -n server command line option in the configuration. The parameters to this option are simply passed through to the nice(2) function. Hence, this option does not work on Windows.

PSPRCSRV        SRVGRP=BASE
                SRVID=101
                MIN=1
                MAX=1
                RQADDR="SCHEDQ"
                REPLYQ=Y
                CLOPT="-n 4 -sInitiateRequest -- -C psprcs.cfg -CD HR88 -PS PSUNX -A start -S PSPRCSRV"
The operating system priority of a process is inherited from its parent. Therefore, lowering the priority of the Process Scheduler running under Tuxedo will also lower the priority of the batch processes that it spawns. 
  • Therefore Stand-alone Application Engine processes (psae) and Cobol processes inherit the priority of the process scheduler server process (PSPRCSRV).
  • However, if the Application Engine server process (PSAESRV) is used, its priority can be set directly. 
There are some potential uses for this approach.
  • If the process scheduler is co-resident with the application server, then it could be run at a lower priority to ensure the online users get preferential allocation of CPU, and that online performance does not suffer excessively at the hands of the batch.
  • A system might have two websites: one for self-service and the other for the 'back-office' users. You could configure separate application servers for each site, and run the self-service application server is run at a lower priority. 

In PeopleSoft, I prefer to create additional variables in the configuration file (psprcs.cfg).

[Process Scheduler]
;=========================================================================
; General settings for the Process Scheduler
;=========================================================================
PrcsServerName=PSUNX
;-------------------------------------------------------------------------
;Reduce priority of Process Scheduler server process, set to 0 if not needed
Niceness=4
...
From PeopleTools 8.4, the Application Engine server process is configured by default. The priority of the AE server processes can then be controlled independently of the process scheduler by creating a separate variable in the PSAESRV section of the configuration file.  However, it is generally better to use standalone PSAE, unless you have many short-lived application engine processes, as in CRM (see Application Engine in Process Scheduler: PSAESRV Server Process -v- Standalone PSAE executable).   
[PSAESRV]
;=========================================================================
; Settings for Application Engine Tuxedo Server
;=========================================================================
;-------------------------------------------------------------------------
;Reduce priority of application engine server process, set to 0 if not needed
Niceness=5
...
In this example, I have reduced the priorities of both the process scheduler and AE servers, but the process scheduler is left with a higher priority than the AE servers. The new variables can then be referenced Tuxedo template file (psprcsrv.ubx).
{APPENG}
#
# PeopleSoft Application Engine Server
#
PSAESRV         SRVGRP=AESRV
                SRVID=1
                MIN={$PSAESRV\Max Instances}
                MAX={$PSAESRV\Max Instances}
                REPLYQ=Y
                CLOPT="-n {$PSAESRV\Niceness} -- -C {CFGFILE} -CD {$Startup\DBName} -S PSAESRV"
{APPENG}
...
PSPRCSRV        SRVGRP=BASE
                SRVID=101
                MIN=1
                MAX=1
                RQADDR="SCHEDQ"
                REPLYQ=Y
                CLOPT="-n {$Process Scheduler\Niceness} -sInitiateRequest -- -C {CFGFILE} -CD {$Startup\DBName} -PS {$Process Scheduler\PrcsServerName} -A start -S PSPRCSRV"
When the domain is configured in psadmin, the variables are resolved in the Tuxedo configuration file (psprcsrv.ubb).  The -n option can be seen in the server command-line options (CLOPT).
#
# PeopleSoft Application Engine Server
#
PSAESRV         SRVGRP=AESRV
                SRVID=1
                MIN=1
                MAX=1
                REPLYQ=Y
                CLOPT="-n 5 -- -C psprcs.cfg -CD HR88 -S PSAESRV"
...
PSPRCSRV        SRVGRP=BASE
                SRVID=101
                MIN=1
                MAX=1
                RQADDR="SCHEDQ"
                REPLYQ=Y
                CLOPT="-n 4 -sInitiateRequest -- -C psprcs.cfg -CD HR88 -PS PSUNX -A start -S PSPRCSRV"