DB2 Web Query Tips and Techniques

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1 DB2 Web Query Tips and Techniques Jackie Jansen Agenda Performance Compute and Define fields DB2 optimization Run w SQL Trace with example Legacy Dates Tips for working with dates InfoAssist performance tip & IE tip Recommendations for prompting parameters Joining Tables Metadata and Applications User Row/Record Security Filters and Business Views Interesting tidbits Data profiling General Tips The Forum & the WIKI Performance / Complexity versus Ease of Use / Simplicity 1

2 Compute vs Define (Virtual Column) Fields Define fields Compute Fields - Virtual Column - RA/GA wizard on right - RA/GA wizard on left - Executed after data is aggregated - Executed on database read - Calculated once for very print line - Calculated once for every record - Calculated after database execution DB2 Performance Recommendation ** Push as much logic as possible down to DB2 ** Use Run w/sql trace option No Run w/sql trace option for InfoAssist Create a simple Report Assistant report containing the specific function you are testing Look for database optimization disablers Use SQL views to overcome database optimization disablers Assume that our database table has 1 million records and 100 distinct dates (output summed by date) 2

3 Performance Example: Convert Legacy Date to Smart Date Output 100 records DB2 retrieved 1 million records Web Query then read 1 million records, summed 1 million records, output 100 records Very, very slow!! Performance Example: Convert Legacy Date to Smart Date Output 100 records DB2 processed 1 million records Web Query receives, formats and outputs 100 records Very, very fast!! Make sure you handle non date values you may have inserted in your date fields (filter out or convert to ) 3

4 Performance Example: Summing Character Fields Performance Example: Summing Character Fields FST. or LST. where sort fields do not cover the key 4

5 Additional DB2 Performance Tips Maximize SQE usage - Avoid SQE Inhibitors Avoid creating metadata over DDS logical files Watch out for Select-Omit logical files against physical files (not as important in V6R1) Both the Heritage File and Query/400 adapter use CQE Use the DB2 CLI adapter if possible Recreate Query/400 reports as new reports that use synonyms based on DB2 CLI adapter No way to avoid it for multi-format files (must use Heritage File adapter) Use SQL Aliases to access multiple members Magic Bullet V1.1.1 Initially use for every report, including single table reports 9 Legacy and Smart Dates Legacy Dates An integer, packed decimal, or alphanumeric format with date edit options, such as I6YMD, A6MDY, I8MDYY, or A8YYMD In Master file indicate date format as USAGE (A8YYMD) Formatted Legacy Date (P8YYMD) 2011/04/01 Mathematically extract components SORT/BY/ACROSS optimized Filter (YEAR = InpParm) Some date arithmetic is optimized Do you need to convert to a Smart Date? Do you need to convert to a Smart Date? - Often Not - Required for: - Monday April 4, Many date arithmetic functions (not all optimized) - Use of calendar icon through HTML Composer 5

6 Numeric Legacy Dates Actual: P8 P6 Usage: P8YYMD P6YMD Output: 2011/04/01 - Dates less than 6 digits use math to create 6 or 8 digit date - i.e. Year * Mth * Day Filter: <= Year <= Do not decompose Legacy date to create a filter - Do NOT filter WHERE YEAR = NumDate / Smart Dates if required: - Must start with an 8 digit field - DATECVT(Date8Num, P8YYMD, YYMD ) - Date Components Required: - DPART(DateFld, P8YYMD, YYMD ) starting with your YYMD field Character Legacy Dates Actual: A8 A6 Usage: A8YYMD A6YMD Output: 2011/04/01 - Use (concatenate) to combine components when less than A8 Filter: - Use SUBSTR to decompose date WHERE YEAR = (SUBSTR(A8Date.)) Smart Dates: Are they required? - Must start with an 8 digit field - DATECVT(DateA8, A8YYMD, YYMD ) - Cannot currently combine Concatenate and DATECVT - For dates less than 8 characters use an SQL View for Summary reports or calendar icons or use a date dimension table 6

7 Legacy Date Optimization Summary 8 Long? Smart Dates Required for: - Formatting January or Friday - Optimizing many date calculations (Use COMPUTE where possible) - Using Calendar icon yes no Formatting / Year filter - num use all 8 digits, alpha use SUBSTR SmartDate: DATECVT DPART 6 Long? yes no 6 Long Alpha or Num? 4/2/2 or 2/2/2/2 or 1/2/2/2 Alpha or Num? alpha num alpha num (Alpha) Formatting / Filter: SUBSTR 8 Long: Concatenate SmartDate: Use SQL View or date dim. table for optimization (num) Use Math to make 8 long SmartDate: DATECVT DPART (Alpha) 8 Long: Concatenate Formatting / SmartDate: Use SQL View or date dim. table for for optimization (num) Use Math to make 8 long Formatting / SmartDate: DATECVT DPART Julian Dates not shown And the Tips just keep coming InfoAssist development performance IE Control key is marvelous! CTL key Tip: Reduce records sent to IE Use prompting or drill down 7

8 Input Parameter Alternatives Creating HTML page front-end Using HTML Composer in Developer Workbench Controls grouped and passed together rather than individually. The more parameters, the better the performance (over Auto Prompt) More efficient i techniques to build the HTML for the drop down lists Aesthetically more options and more pleasing Usage Tip Consider HTML Composer with calendar icons for date prompting Joining Tables Use DB2 Foreign Key support if possible Developer Workbench Reference existing synonyms R1.1.2 system will try to autojoin the two tables you select In reporting tool 16 8

9 Metadata Synonyms can be placed in application folders and associated with Domains Only members of group profile can access those synonyms Metadata will automatically go into first application in domain s application list Developers working in Developers Workbench will see the application folders under the domains that they are authorized to. Administrators only will see Data Servers containing all metadata applications Developer Administrator User Row/Record Security Alternatives Complete security including securing developers SQL Views! Join to a table containing userid and security values Allows for more complex selection Very fast: DB2 optimization and checking JJANSEN SMITH SMITH JJANSEN JONES Today a developer can simply create their own synonym and bypass secured synonyms See white paper on DB2 Web Query website DBA Store security data and information directly in synonym Optimized DB2 Details next slide Web Query Join Create table with userid and authority values Join Security table to master file with secured field (i.e. COUNTRY) Retrieve run time userid Select records where run time user equals security userid In Report, compare user to &FOCUSER &FOCUSER optimized Report developer makes security decision In Master File have to use GETUSER( 10 ) NOT optimized CANADA GERMANY UNITED STATES UNITED STATES UNITED STATES 9

10 DBA Jackie DEMOADMIN DEMODEV Filters and Business Views Global Filters Report designer can easily select and reuse i.e. Europe filter might automatically select all countries in Europe Modified filters automatically used by all existing reports Business Views Simplify list of columns by categorizing fields within folders Reduce fields user sees (simplicity and security) 10

11 More Questions More Answers 1) Question: How to display graphic indications of performance? Answer: Wingdings font with conditional styling. 2) Question: How to have a calculation at subtotal and not at detail level. Answer: Subfootings and Prefixes. 3) Question: My field length has changed. What is effected? Answer: Developer Workbench: Impact Analysis TIP: different analysis based on starting point: reports or master files Developer Workbench: Data Profiling By column / table / cluster / view Pattern count, outliers Identifies Avg, Min/Max Number of distinct Values % of Nulls 11

12 General Tips Multi-member file support Can use the Heritage File adapter uses OPNQRY and CQE Creating an alias will use SQE CREATE ALIAS MYLIB/MYALIAS FOR MYLIB/FILENAME (MBRNAME) SQL Wizard type or import an SQL statement Part of Developer Workbench Result set is sent to RA/GA for formatting Developer Workbench Confirm Close Use this setting Show Desktop on Explorer Tree General Tips Create Domain names with exactly eight characters and then change the displayed name in the Domain properties Consider using a Prefix for synonym names to assist in grouping related tables together Backup libraries and IFS SAVLIB QWEBQRY76 and QWEBQRY77 Sav - /QIBM/PRODDATA/WEBQUERY/IBI/* Sav - /QIBM/USERDATA/WEBQUERY/IBI/* Use style sheets to format your reports You can modify provided style sheets or create your own.sty and.css RA style sheets need copying into Other Files (redbook gives details) IA style sheets are instantly available RA/GA/PP prompt for parameter ParameterName.Prompt_Text. 12

13 The Forum and the WIKI IBM developerworks site for DB2 Web Query Registration g Recommended KnowledgeBase and Forum Links to Additional Information WIKI Repository of technical information DB2 Web Query home page Getting Started with DB2 Web Query Redbook Download Sample Database 13