Application Performance for DB 2 Wayne Slomiany January

Application Performance for DB 2 Wayne Slomiany January 29, 2008

Agenda • Targeted DB 2 Data for Testing • Efficient Coding Practices • Efficient Application Relationships • Using DB 2 Stored Procedures • Resolving DB 2 Abends • External Influences 2

Targeted DB 2 Data for Testing Audit Reports z/O S Distribut ed 3 Subset Extrac t Apply Privacy Rules Privacy Audit Reports Load Mainta in Integrit y z/OS Distribut ed

Less Data, Less Resources • Large TABLE loads can cause excessive resource usage and long LOAD times. • Optimization of data used will decrease this. • Usage of tools that support SORTKEYS in the load process which bypasses INDEX Key validation on each KEY written. • Specifying LOG NO will prevent logging. 4

Relationships of Data Intact • Referential Integrity • Application Relationships 5

Data Relationships Production Subset Extrac Distributed t 6

z/OS Relationships Production AR/RI z/OS 7

Efficient Coding Practices “The later performance problems are caught in the life cycle, the more costly they are to fix. Inefficiencies introduced in design can cost twice as much to fix during programming, four times more during system testing, and eight times more when the application enters production. ” Accenture 8

Pro-Active Application Relationship Management • Normalize Database Including Application Relationships during Logical Design Phase − Those used in Programs − Those used in Driving Files • Perform Physical Design (Table and Index) de-Normalizing for Performance 9

Pro-Active Application Relationship Management • Table joins tend to cause de-Normalization to improve performance. • Focus on proper creation of INDEXs. • Make Only Acceptable Relationships Available to Applications. 10

Create a Baseline of the Application • Identify what is acceptable (SLAs) for a particular application. − End User response times. − Overall system performance. − Overall resource usage. • Use this to compare future releases and Production. − Identify problem areas. − Identify any changes made. 11

Benefits of DB 2 Stored Procedures • • Reduce Network traffic Improve Security Called from many programs/platforms Easier to maintain data & logic CICS/ IMS Batch Browser Middleware Data Servers S 390 Servers 12

DB 2 Stored Procedures • They reduce the SQL statements needed in the calling program. • SQL is executed by the stored procedure and results are returned to the calling program. • They have separate authority from the caller, allowing them to access and update tables that the caller can’t. 13

DB 2 Stored Procedures • The caller only needs authorization to execute the stored procedure. • This provides an additional level of security by preventing corruption of the SQL. • This also eliminates outdated Client processes, the current stored procedure is always executed. 14

DB 2 Stored Procedures • They must run using Language Environment. • If a stored procedure does abend, there is only the LE dump to work with. • The programmer could add his own trace code to try to narrow down the cause of the abend. 15

DB 2 Stored Procedures Challenges Added Complexity Analysis Programmer Familiarity Debugging Testing Production Support 16 Project Deadlines - PLUS - Prevent Problems Customer Satisfaction Realize Benefits

XPEDITER for DB 2 Stored Procedures ---------- XPEDITER/TSO - Process DB 2 Store Procedures -------COMMAND ===> Primary Commands: SEtup (display setup menu) Stored Procedure Name Load Module name Client End User Name DB 2 Auth. ID Luname DB 2 Sub System Name Maximum number of Tests Specify Execute Jcl ===> ===> DOE. SPTEST 1 PGM 12345 JOHNDOE (optional) (DB 2 Version 5 only) DB 61 TEST (1 - 9999) ===> N (Y or N) Jobcard Information: ===> //PFHRAS 0 JOB (#ACCONT), CLASS=A, MSGCLASS=X, ===> // MSGLEVEL=(1, 1) Press ENTER to process 17 or enter END command to terminate

XPEDITER for DB 2 Stored Procedures -----------COMMAND ===> XPEDITER/TSO - SELECT JOB STEP ----- Row 1 to 1 of 1 SCROLL ===> PAGE Line I U IC UC Commands: Primary Commands: - Interactive testing Edit - Display converted selected steps - Unattended testing END - Exit without processing - Interactive Code Coverage RUN - Submit and connect - Unattended Code Coverage SEtup - Setup work datasets SUBmit - Convert selected steps and submit blank - Reset I/U/C STatus - Display status of submitted job(s) Dataset: 'SYS 1. PROCLIB(D 61 WLM 2)' PROGRAM INITSCR STEPNAME PROCSTEP EXEC PGM --------------------------------------__ PGM 12345 ____ XPTS 0 XPAE 001 RUNPROG XPTSO **************** Bottom of data **************** 18

XPEDITER for DB 2 Stored Procedures ------------- XPEDITER/TSO - SOURCE ---------------COMMAND ===> SCROLL ===> CSR BEFORE BREAKPOINT ENCOUNTERED ** END ** ---------------------------- Before PGM 12345<> =====> B FUNCTION = 'COMMAND'; /* SET FUNCTION FOR IFI CALL */ 000265 IFCA. LNGTH = STORAGE(IFCA); /* BYTES USED IN MEMORY */ 000266 IFCA. EYE_CATCHER = 'IFCA'; /* EYE CATCHER */ 000267 IFCA. OWNER_ID = 'LOC 2'; /* DB 2 LOCATION 1=LOCAL, 2=REMOTE*/ 000268 FREE RETURN_AREA; /* FREE STORAGE AND THEN */ 000269 /* ALLOCATE STORAGE FOR THE */ 000270 ALLOCATE 1 RETURN_AREA, /* RETURN AREA */ 000271 2 LNGTH, 000272 2 RTRN_BUFF CHAR(4096); 000273 000274 RTRN_BUFF = ' '; /* CLEAR THE RETURN BUFFER */ 000275 RETURN_AREA. LNGTH = 4096; /* LENGTH OF RETURN BUFFER */ 000276 TEXT_OR_COMMAND=BLANK; /* CLEAR THE DB 2 COMMAND AREA*/ 000277 OUTPUT_AREA. UNUSED = '0000'B; /* CLEAR THE UNUSED AREA */ 000278 OUTPUT_AREA. LNGTH = LENGTH(INPUTCMD)+4; /* GET REAL LENGTH OF */ 000279 OUTPUT_AREA. TEXT_OR_COMMAND = INPUTCMD; /* ACTUAL DB 2 COMMAND */ 19

Resolving DB 2 Application Abends • Abends, including DB 2, can use a large portion of the processor. • Resolving them in a quick and complete fashion is important. • Correlation of Application and DB 2 information is important in resolution. 20

CICS Application Abend • Locate the task interface element (TIE) for “DSNCSQL”. • Locate the CICS Life of Task (CLOT) in the TIE for DSNCSQL. Locate the • • SQL-PLIST using the pointer (CLOTPARM) from the CLOT. Validate the SQL-PLIST by locating the DBRM name once the SQL-PLIST is verified, the statement number, type, APARM (INPUT Host Variables) address, VPARM (OUTPUT Host variables) address, timestamp and pointer to the SQLCA have been located. To locate the SQLCODE, use the SQLCA pointer from the SQL-PLIST. Once located, the SQLCODE must be converted from HEX to DECIMAL before it can be used. For example, A -302 displays as “FFFFFED 2” in the SQLCA. Look up the SQLCODE in the DB 2 message and codes manual. The message text does not offer much more than an explanation. • There are seldom any suggestions as to the cause of the problem. • The statement number is used to locate the SQL statement in the precompile listing. 21

Using Correlation 22

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Application Management Solution Reduce excessive resource consumption at the root cause through a proactive and systemic approach. Application Resource Management provides empirical data to help you make educated decisions. 26

External Influences Database Utilization Delivery Stats Server Performance Application Servers Database Servers Web Servers J 2 EE and. NET Analyzer End user monitoring Top App by Traffic Service Dashboard Top Server Traffic WAN Utilization Response Times Performance Overview 27

Distributed MQ Application Client Query N-Tier Server Back end Server Request 1 Reply 1 1. Web application was occasionally failing. 2. Became aware of problem in real time (without any user interaction). Also got background information: unexpected 2033. Pdaaggr. exe Answer 28 3. Traced the MQ message flow and saw that the 2033 was Reply 2 due to sluggish response from the Request 3 mainframe application. Request 2 Reply 3 Request 4 Reply 4 4. Analyzed the performance of the mainframe application – and saw a significant issue with MQ system-level tracing during bursts of activity. Pdarep 2

MQ Performance Impact • Excessive wait time can impact DB 2 performance. • Difficult to identify the culprit. 29

Environment Tuning • Evolving applications introduce more potential points of failure • Environmental complexity contributes to resource growth • Gradual MIPS consumption can go undetected 30 • Reactive, fire-fighting mindset • Limited expertise and skills • Mainframe costs (hardware and software) are driven by MIPS

Dynamic SQL Queries • Usually rarely used however has great impact. • Can involve large table scans with long wait times at the user end. • Minimize and control as best possible. 31

DB 2 Environment Considerations • Manage BUFFER POOLS based on recommendations per Version of DB 2. • Proper BUFFER POOL sizes: a good indicator is ratio of GETPAGES to synchronous reads of no greater than 10: 1. • There is a difference between read-only and read/write tables (maybe a separate BUFFER POOL here). 32

Current Application Performance Metrics 33