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TechTip: A Way to Capture SQL Statements |
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Written by MC Press Contributing Author
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Sunday, 13 April 2003 |
For anyone in the IS/IT departments, SQL can be a very useful and productive tool. However, it can be a dangerous and untraceable process as well. We have found a trick that is very handy for monitoring and troubleshooting data integrity issues.
One of the most common methods of using SQL is by using the STRSQL command. We have modified this command to call our own CL prior to execution of the "real" STRSQL command.
To use this utility, you must have library QUSRSYS defined above QSYS in your system library list. You must create a STRSQL command in QUSRSYS that points to the program CUCSTRSQL, shown in Figure 1.
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/*------------------------------------------------------------------*
/* COMMAND.....: STRSQL WRAPPER AROUND STRSQL COMMAND *
/* EXECUTES....: CUCSTRSQL *
/* 1- LOG USER ? *
/* PROGRAMMER..: DAVE BURT 2- LIMIT TIME TO 200 SECONDS *
/* WRITTEN.....: 11/19/01 *
/* *
/* DESCRIPTION: *
/* *
/*------------------------------------------------------------------*
CMD PROMPT('START SQL WITH WRAPPER')
/*------------------------------------------------------------------*/
/* PROGRAM.....: CUCSTRSQL START SQL (STRSQL) WITH LIMITS */
/* PROGRAMMER..: DAVE BURT AND LOGGING */
/* WRITTEN.....: 11/19/01 */
/* */
/* CALLED BY...: QUSRSYS/STRSQL */
/* */
/*------------------------------------------------------------------*/
PGM
DCL VAR(&USER) TYPE(*CHAR) LEN(10)
DCL VAR(&NAME) TYPE(*CHAR) LEN(50)
/* GET USER INFORMATION */
RTVJOBA USER(&USER)
RTVUSRPRF TEXT(&NAME)
/* OVERRIDE MESSAGE CHECKING AND SQL LIMIT */
CALL PGM(CUCJOBCTL) PARM('S')
MONMSG CPF0000
/* SHOW MESSAGE */
SHOWAMSG MESSAGE('SQL processing time will be limited +
to 200 seconds.')
/* LOG START */
CALL PGM(CURSQLLOG) PARM(&USER &NAME 'START')
MONMSG CPF0000
CALL PGM(CUCDBMON ) PARM('S')
MONMSG CPF0000
/* REAL SQL */
? QSYS/STRSQL
MONMSG CPF0000
/* LOG STOP */
CALL PGM(CURSQLLOG) PARM(&USER &NAME 'STOP ')
MONMSG CPF0000
CALL PGM(CUCDBMON ) PARM('E')
MONMSG CPF0000
/* BACK TO NORMAL */
CALL PGM(CUCJOBCTL) PARM('N')
MONMSG CPF0000
ENDOFPGM:
ENDPGM
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Figure 1: Program CUCSTRSQL
As you can see, we call several programs within this CL. You may choose to include or exclude any of these programs in your copy.
The first program called (CUCJOBCTL – SQL Limit) defines a limitation that we set using the Change Query Attributes (CHGQRYA) command to limit the SQL and query processing to 200 seconds. Because we had a large number of people querying the database, the system was being tasked with large statement returns. This limitation helped performance.
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/*------------------------------------------------------------------*/
/* PROGRAM.....: CUCJOBCTL */
/* PROGRAMMER..: DAVE BURT */
/* WRITTEN.....: 11/20/01 */
/* */
/* */
/* */
/*------------------------------------------------------------------*/
PGM PARM(&ACTION)
DCL VAR(&ACTION) TYPE(*CHAR) LEN(1)
IF COND(&ACTION = 'S') THEN(DO)
CHGQRYA QRYTIMLMT(200)
CHGJOB INQMSGRPY(*SYSRPYL)
ENDDO
ELSE CMD(DO)
CHGQRYA QRYTIMLMT(*NOMAX)
CHGJOB INQMSGRPY(*RQD)
ENDDO
ENDPGM
****************** End of data ************************
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Figure 2: Program CUCJOBCTL
The next program called, CURSQLLOG, logs the SQL statement that is executed. This program logs only the statement, not the returned data. The statement is written to a file that can be queried later for auditing purposes.
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************** Beginning of data ************************************
*-------------------------------------------------------------------*
* Program....: CURSQLLOG Write Start/Stop Records for SQL *
* Programmer.: Dave Burt LOG *
* Written....: 11/21/01 *
* *
* Called by..: CUCSTRSQL *
*-------------------------------------------------------------------*
*----------------------------------------------------------------*
* Files
*----------------------------------------------------------------*
cupsqllog o a e disk
*----------------------------------------------------------------*
* Fields
*----------------------------------------------------------------*
pgmUser s 10a
name s 50a
action s 10a
today s 6s 0
now s 6s 0
timedate s 12s 0
dateYMD s D datfmt(*YMD)
sds
*----------------------------------------------------------------*
* Main Routine
*----------------------------------------------------------------*
*entry plist
parm pgmUser
timedate s 12s 0
dateYMD s D datfmt(*YMD)
sds
*----------------------------------------------------------------*
* Main Routine
*----------------------------------------------------------------*
*entry plist
parm pgmUser
parm name
parm action
time timedate
move timedate today
*MDY move today dateYMD
move dateYMD today
movel timedate now
eval squser = pgmUser
eval sqname = name
eval sqdate = today
eval sqtime = now
eval sqaction = action
eval sqsql = action
write sqlrcd
eval *inlr = *on
***************** End of data *****************
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Figure 3: Program CURSQLLOG
The next CL program, CUCDBMON, runs the database monitor as *OWNER (since users might not have the rights needed to run this monitoring program):
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*************** Beginning of data *************************************
/*------------------------------------------------------------------*/
/* PROGRAM.....: CUCDBMON START OR STOP DATABASE MONITOR */
/* PROGRAMMER..: DAVE BURT USING *OWNER AUTORITY */
/* WRITTEN.....: 08/19/99 */
/* */
/* DESCRIPTION: */
/* */
/* */
/*------------------------------------------------------------------*/
PGM PARM(&ACTION)
DCL VAR(&ACTION) TYPE(*CHAR) LEN(1)
CALL PGM(CUCDBMON2) PARM(&ACTION)
ENDPGM
****************** End of data ****************************************
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Figure 4: Program CUCDBMON
The CUCDBMON2 program runs the monitoring portion of the capture process. It returns the data to file DBMON.
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*************** Beginning of data ************************************
/*------------------------------------------------------------------*/
/* PROGRAM.....: CUCDBMON2 START OR STOP DATABASE MONITOR */
/* PROGRAMMER..: DAVE BURT USING *OWNER AUTORITY */
/* WRITTEN.....: 08/19/99 */
/* */
/* DESCRIPTION: */
/* */
/* */
/*------------------------------------------------------------------*/
PGM PARM(&ACTION)
DCL VAR(&ACTION) TYPE(*CHAR) LEN(1)
DCL VAR(&USER ) TYPE(*CHAR) LEN(10)
RTVJOBA USER(&USER)
/* START */
IF COND(&ACTION = 'S') THEN(DO)
STRDBMON OUTFILE(CUSTOM/DBMON) OUTMBR(&USER)
ENDDO
/* STOP AND CALL LOG PROGRAM */
ELSE CMD(DO)
ENDDBMON
OVRDBF FILE(DBMON) TOFILE(CUSTOM/DBMON) MBR(&USER) +
OVRSCOPE(*JOB)
CALL PGM(CURDBMON) PARM(&USER)
DLTOVR FILE(DBMON) LVL(*JOB)
ENDDO
ENDPGM
****************** End of data **************************************
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Figure 5: Program CUCDBMON2
The program call from CURDBMON extracts the log records that were captured in the monitor program.
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************** Beginning of data ************************************
*-------------------------------------------------------------------*
* Program....: CURDBMON Extract log records from Start *
* Programmer.: Dave Burt Database Monitor. *
* Written....: 11/21/01 *
* *
* *
* Called by..: CUCDBMON2 *
* *
* COMPILE WITH ALWNULL(*YES)
* *
* Modifications: *
* *
*-------------------------------------------------------------------*
*----------------------------------------------------------------*
* Files
*----------------------------------------------------------------*
dbmon if e disk
cupsqllog if a e k disk
*----------------------------------------------------------------*
* Fields
*----------------------------------------------------------------*
user s 10a
uCase c const('ABCDEFGHIJKLMNOPQR-
STUVWXYZ')
lCase c const('abcdefghijklmnopqr-
stuvwxyz')
yes c const('Y')
no c const('N')
vFlag s 1a
text s 1002a
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