Tag Archives: performance tuning

Find time between records in a logging table with DB2

One trick I’ve used for quite a while is to have stored procs “log” information to a table with the structure…

XX.SYS_PROC_AUD
(
PROC_X,
ACTIVITY_X,
CREATED_TS,
ERROR_NB
)

…which is great for seeing what’s going on across the board, on a proc by proc basis, or looking for specific things. But what about when management request “metrics” about how things are running? Well, since I already log stop and start of the procs to the aforementioned table, you can use a WITH query to help get run times of procs and even between procs without resorting to Excel like so…

WITH    rows AS
        (
        SELECT  ROW_NUMBER() OVER (ORDER BY CREATED_TS) AS rn, CREATED_TS, PROC_X
        FROM    XX.SYS_PROC_AUD  
        WHERE   (
                PROC_X = 'XX.FIRST_PROC_P'  
			    AND ACTIVITY_X = 'Starting Exec'  
                )
                OR
                (
                PROC_X = 'XX.LAST_PROC_P'  
			    AND ACTIVITY_X = 'Finished Exec'  
                )
        ORDER BY CREATED_TS DESC
        FETCH FIRST 1000 ROWS ONLY WITH UR
        )
SELECT  mc.CREATED_TS as START_TS, 
        mp.CREATED_TS as END_TS, 
        TIMESTAMPDIFF(2, CHAR(mp.CREATED_TS - mc.CREATED_TS)) AS SEC, 
        TIMESTAMPDIFF(2, CHAR(mc.CREATED_TS - mpe.CREATED_TS)) AS SEC_BETWEEN_LAST
FROM    rows mc
            INNER JOIN rows mp
                ON mc.rn = mp.rn - 1
            INNER JOIN rows mpe
                ON mc.rn = mpe.rn + 1
WHERE   mc.PROC_X = 'XX.FIRST_PROC_P'
ORDER BY mc.CREATED_TS DESC
FETCH FIRST 100 ROWS ONLY WITH UR FOR READ ONLY

Note: I prefer to see the most recent things first so you may need to adjust your ordering appropriately if you don’t like that setup.

Thanks to this post for getting me started.

DB2: When were index stats last updated on a table?

To find out when stats were updated for an index, run the following SQL substituting your schema and table names…

SELECT  IND.TABSCHEMA,
        IND.TABNAME,
        IND.INDNAME,
        IND.COLNAMES,
        IND.STATS_TIME AS IDX_STATS_TIME, 
        T.STATS_TIME TBL_STATS_TIME, 
        CASE T.VOLATILE
            WHEN 'C' THEN 'YES'
            ELSE T.VOLATILE
        END AS TBL_VOLATILE,
        T.OWNERTYPE AS TBL_OWNERTYPE,
        T.TYPE AS TBL_TYPE
FROM    SYSCAT.INDEXES IND 
            LEFT OUTER JOIN SYSCAT.TABLES T
                ON IND.TABSCHEMA = T.TABSCHEMA
                    AND IND.TABNAME = T.TABNAME
WHERE   T.OWNERTYPE != 'S'
        AND IND.TABNAME = 'MY_TABLE' 
        AND IND.TABSCHEMA = 'XX' 
ORDER BY 
        IND.TABSCHEMA,
        IND.TABNAME,
        IND.INDNAME 
FOR READ ONLY WITH UR;

Analyzing a Memory Leak in a Java Application

In trying to diagnose an Out of Memory error in a large Java application, a co-worker of mine (Chad Handrich) came across the article Analyzing a Memory Leak in Java Applications using VisualVM and used the tips in it to find a memory leak that had been causing OOM errors for quite some time.

He also found that another helpful tool is the “Performance Monitor” app that comes with Windows. To use it, create a new “User Defined Data Collector Set”. Choose the option “Create Manually”, then “Performance Counter”, then you can select “Process”, and choose all the byte-count style counters if analyzing memory usage. And choose the “java.exe” instance from the list. Once it’s created, right click the collector you made and select “Start”. It will begin polling and saving the metrics you specified.

DB2 Stored Proc Performance Analysis

Have you ever wondered what tables and indexes a DB2 stored proc are using? How about if the proc has been rebound since the stats were last updated? Are there even stats for the table you’re querying? Luckily I work with a very talented application DBA (Fred Johnson) who put together the following query to tell you all these sorts of things. It’s quite long, but all you need to do is set your proc in the “FILTER_PARMS” “VALUES” section at the top of the query.

-------------------------------------------------------------------------
-- DB2 for AIX QUERY
--PROCS WITH DEPENDENT TABLES INDEXES CALLED_PROCS AND OTHER OBJECTS 
--FLAG column shows possible stats issues.  See FOOTNOTES
-------------------------------------------------------------------------
-- Directions: Change FILTER_PARMS,Cut and paste, run, examine output
--             More than 1 proc can be reviewed by adding addition lines
-------------------------------------------------------------------------
WITH FILTER_PARMS   (ROUTINESCHEMA,ROUTINENAME) AS 
            (VALUES 
                                ('XX','PROC1_P') 
                               ,('XX','PROC2_P')
                       )    
,ROUTINEDEP (STOREDPROC,TEXTX,OBJECTNAME,CARD,BIND_STATS_CREATE_TIME,FLAG,SORTCOL) AS
(SELECT RTRIM(X.ROUTINESCHEMA)||'.'||X.ROUTINENAME AS STOREDPROC , 
        'PACKAGE' AS TEXTX ,RTRIM(P1.PKGSCHEMA)||'.'||P1.PKGNAME AS 
        OBJECTNAME ,' ' AS CARD
               , 'BIND:   '||CHAR(DATE(P1.LAST_BIND_TIME))||'*'||CHAR(TIME(P1.LAST_BIND_TIME)) 
               AS BIND_STATS_CREATE_TIME 
               ,CASE
               WHEN  P1.LAST_BIND_TIME < CURRENT_TIMESTAMP - 9 DAYS
               THEN '*STALE REBIND ' ELSE ' ' 
                END
                 ||
        CASE
          WHEN P1.VALID = 'N' THEN '*PACKAGE INVALID '
          WHEN P1.VALID = 'X' THEN '*PACKAGE INOPERATIVE '
          ELSE '' END  
                
                 AS FLAG 
               ,RTRIM(X.ROUTINESCHEMA)||X.ROUTINENAME||'1' AS SORTCOL
      FROM SYSCAT.PACKAGES P1
        INNER JOIN SYSCAT.ROUTINEDEP R
        ON (P1.PKGNAME = R.BNAME
           AND P1.PKGSCHEMA = R.ROUTINESCHEMA)
        INNER JOIN  SYSCAT.ROUTINES X
        ON (R.ROUTINENAME = X.SPECIFICNAME
          AND R.ROUTINESCHEMA = X.ROUTINESCHEMA)
        INNER JOIN FILTER_PARMS FP
         ON (FP.ROUTINESCHEMA  = X.ROUTINESCHEMA 
             AND FP.ROUTINENAME =  X.ROUTINENAME)
         UNION
    --TABLES
    SELECT ' ' AS STOREDPROC , CASE
          WHEN P.BTYPE = 'A' THEN 'ALIAS'
          WHEN P.BTYPE = 'B' THEN 'TRIGGER'
          WHEN P.BTYPE = 'D' THEN 'SERVER DEF'
          WHEN P.BTYPE = 'F' THEN 'PROC/FUNC'
          WHEN P.BTYPE = 'I' THEN 'INDEX'
          WHEN P.BTYPE = 'M' THEN 'FUNCTION MAP'
          WHEN TAB.TYPE = 'N' THEN 'NICKNAME'
          WHEN P.BTYPE = 'O' THEN 'PRIVILEGE DEP'
          WHEN P.BTYPE = 'P' THEN 'PAGE SIZE'
          WHEN P.BTYPE = 'R' THEN 'STRUCT TYPE '
          WHEN P.BTYPE = 'S' THEN 'MQTABLE'
          WHEN P.BTYPE = 'T' THEN 'TABLE'
          WHEN P.BTYPE = 'U' THEN 'TYPED TABLE'
          WHEN P.BTYPE = 'V' THEN 'VIEW'
          WHEN P.BTYPE = 'W' THEN 'TYPED VIEW'
          ELSE ' ?' END AS TEXTX  ,RTRIM(P.BSCHEMA)||'.'||
        P.BNAME AS OBJECTNAME ,RTRIM(CHAR(TAB.CARD)) AS CARD 
                ,'STATS:'||COALESCE(CHAR(DATE(TAB.STATS_TIME))||'*'||CHAR(TIME(TAB.STATS_TIME)) ,'NO STATS')
                 AS BIND_STATS_CREATE_TIME
        ,CASE
          WHEN TAB.CARD = -1
          THEN '*NO TABLESTATS'
          WHEN TAB.STATS_TIME > P1.LAST_BIND_TIME
            THEN '*PROC BIND < STATS'
          ELSE ' '
        END 
        ||
        CASE
          WHEN  TAB.STATUS <> 'N'
            THEN '*STATUS '||RTRIM(TAB.STATUS)
          ELSE '' 
        END 
        AS FLAG
        
         ,RTRIM(X.ROUTINESCHEMA)||X.ROUTINENAME||'2'||RTRIM(
        P.BSCHEMA)||'.'||P.BNAME||'2' AS SORTCOL
      FROM SYSCAT.PACKAGES P1
        INNER JOIN SYSCAT.ROUTINEDEP R
        ON (P1.PKGNAME = R.BNAME
           AND P1.PKGSCHEMA = R.ROUTINESCHEMA)
        INNER JOIN  SYSCAT.ROUTINES X
        ON (R.ROUTINENAME = X.SPECIFICNAME
          AND R.ROUTINESCHEMA = X.ROUTINESCHEMA)
        INNER JOIN FILTER_PARMS FP
         ON (FP.ROUTINESCHEMA  = X.ROUTINESCHEMA 
             AND FP.ROUTINENAME =  X.ROUTINENAME)
        INNER JOIN SYSCAT.PACKAGEDEP P
        ON (P1.UNIQUE_ID = P.UNIQUE_ID
        AND P.PKGNAME = R.BNAME
        AND P.PKGSCHEMA = R.ROUTINESCHEMA)
       
        INNER JOIN SYSCAT.TABLES TAB
        ON (P.BSCHEMA = TAB.TABSCHEMA
            AND P.BNAME = TAB.TABNAME
             AND P.BTYPE IN ( 'T','N','S','U','W'))
    UNION
      --INDEXES
    SELECT ' ' AS STOREDPROC , '            INDEX' AS TEXTX ,RTRIM(P.BSCHEMA)
        ||'.'||P.BNAME AS OBJECTNAME ,RTRIM(CHAR(IND.FULLKEYCARD)) AS CARD
               ,'STATS:'||COALESCE(CHAR(DATE(IND.STATS_TIME))||'*'||CHAR(TIME(IND.STATS_TIME)),'NO STATS')
               AS BIND_STATS_CREATE_TIME 
        ,CASE
          WHEN IND.FULLKEYCARD = -1
          THEN '*NO INDEXSTATS'
          WHEN IND.STATS_TIME > P1.LAST_BIND_TIME THEN '*PROC BIND < STATS '
                  ELSE ''
          END 
               ||CASE
          WHEN IND.STATS_TIME < TAB.STATS_TIME - 10 SECONDS
            THEN '** IND.STATS_TIME < TAB.STATS_TIME'
          ELSE '' END AS FLAG 
                ,RTRIM(X.ROUTINESCHEMA)||X.ROUTINENAME||'2'||RTRIM(IND.TABSCHEMA)||'.'||IND.TABNAME||'3'
               AS SORTCOL
      FROM      SYSCAT.PACKAGES P1
        INNER JOIN SYSCAT.ROUTINEDEP R
        ON (P1.PKGNAME = R.BNAME
           AND P1.PKGSCHEMA = R.ROUTINESCHEMA)
        INNER JOIN  SYSCAT.ROUTINES X
        ON (R.ROUTINENAME = X.SPECIFICNAME
          AND R.ROUTINESCHEMA = X.ROUTINESCHEMA)
        INNER JOIN FILTER_PARMS FP
         ON (FP.ROUTINESCHEMA  = X.ROUTINESCHEMA 
             AND FP.ROUTINENAME =  X.ROUTINENAME)
        INNER JOIN SYSCAT.PACKAGEDEP P
        ON (P1.UNIQUE_ID = P.UNIQUE_ID
        AND P.PKGNAME = R.BNAME
        AND P.PKGSCHEMA = R.ROUTINESCHEMA)
        INNER JOIN SYSCAT.INDEXES IND 
         ON (P.BSCHEMA = IND.INDSCHEMA
         AND P.BNAME = IND.INDNAME
        AND  P.BTYPE = 'I')
        INNER JOIN SYSCAT.TABLES TAB
        ON (IND.TABSCHEMA = TAB.TABSCHEMA
        AND IND.TABNAME = TAB.TABNAME)
    UNION
    SELECT ' ' AS STOREDPROC , '        OTHER '||
        CASE
          WHEN XDEP.ROUTINETYPE = 'F' THEN 'FUNCTION '
          WHEN XDEP.ROUTINETYPE = 'M' THEN 'METHOD'
          WHEN XDEP.ROUTINETYPE = 'P' THEN 'STORED PROC'
          ELSE ' ?'  END AS TEXTX
               ,RTRIM(XDEP.ROUTINESCHEMA)||'.'||XDEP.ROUTINENAME AS OBJECTNAME 
               ,' ' AS CARD 
               ,'CREATED:'||CHAR(DATE(XDEP.CREATE_TIME))
                 AS BIND_STATS_CREATE_TIME
               ,CASE 
                 WHEN XDEP.ROUTINETYPE = 'P' 
                 THEN CASE
                      WHEN NOT EXISTS
                      (SELECT 1
                        FROM FILTER_PARMS FP
                WHERE  FP.ROUTINESCHEMA  =  XDEP.ROUTINESCHEMA
                   AND FP.ROUTINENAME    =  XDEP.ROUTINENAME)
               THEN  ','||'('||''''||RTRIM(XDEP.ROUTINESCHEMA)
                        ||''''||','||''''||RTRIM(XDEP.ROUTINENAME)
                        ||''''||')' 
               ELSE ' ' END
                 ELSE ' ' END AS FLAG  --('CH','GET_NEXTID_P') 
        ,RTRIM(X.ROUTINESCHEMA)||X.ROUTINENAME||'3' AS SORTCOL
      FROM SYSCAT.PACKAGES P1
        INNER JOIN SYSCAT.ROUTINEDEP R
        ON (P1.PKGNAME = R.BNAME
           AND P1.PKGSCHEMA = R.ROUTINESCHEMA)
        INNER JOIN  SYSCAT.ROUTINES X
        ON (R.ROUTINENAME = X.SPECIFICNAME
          AND R.ROUTINESCHEMA = X.ROUTINESCHEMA)
        INNER JOIN FILTER_PARMS FP
         ON (FP.ROUTINESCHEMA  = X.ROUTINESCHEMA 
             AND FP.ROUTINENAME =  X.ROUTINENAME)
        INNER JOIN SYSCAT.PACKAGEDEP P
        ON (P1.UNIQUE_ID = P.UNIQUE_ID
        AND P.PKGNAME = R.BNAME
        AND P.PKGSCHEMA = R.ROUTINESCHEMA)
       INNER JOIN SYSCAT.ROUTINES XDEP
       ON (P.BNAME = XDEP.SPECIFICNAME
        AND P.BSCHEMA = XDEP.ROUTINESCHEMA)
        UNION
      --OTHER
     SELECT ' ' AS STOREDPROC , '        OTHER '||
        CASE
          WHEN P.BTYPE = 'A' THEN 'ALIAS'
          WHEN P.BTYPE = 'B' THEN 'TRIGGER'
          WHEN P.BTYPE = 'D' THEN 'SERVER DEF'
          WHEN P.BTYPE = 'F' THEN 'PROC/FUNC'
          WHEN P.BTYPE = 'I' THEN 'INDEX'
          WHEN P.BTYPE = 'M' THEN 'FUNCTION MAP'
          WHEN P.BTYPE = 'N' THEN 'NICKNAME'
          WHEN P.BTYPE = 'O' THEN 'PRIVILEGE DEP'
          WHEN P.BTYPE = 'P' THEN 'PAGE SIZE'
          WHEN P.BTYPE = 'R' THEN 'STRUCT TYPE '
          WHEN P.BTYPE = 'S' THEN 'MQTABLE'
          WHEN P.BTYPE = 'T' THEN 'TABLE'
          WHEN P.BTYPE = 'U' THEN 'TYPED TABLE'
          WHEN P.BTYPE = 'V' THEN 'VIEW'
          WHEN P.BTYPE = 'W' THEN 'TYPED VIEW'
          WHEN P.BTYPE = 'Q' THEN 'Sequence object'
          WHEN P.BTYPE = 'G' THEN 'Global temporary table'
          ELSE ' ?'||RTRIM(P.BTYPE) END AS TEXTX 
                 ,RTRIM(P.BSCHEMA)||'.'||P.BNAME AS OBJECTNAME 
                 ,' ' AS CARD
                 , '' AS BIND_STATS_CREATE_TIME ,' '
        AS FLAG ,RTRIM(X.ROUTINESCHEMA)||X.ROUTINENAME||'4' AS SORTCOL
      FROM SYSCAT.PACKAGES P1
        INNER JOIN SYSCAT.ROUTINEDEP R
        ON (P1.PKGNAME = R.BNAME
           AND P1.PKGSCHEMA = R.ROUTINESCHEMA)
        INNER JOIN  SYSCAT.ROUTINES X
        ON (R.ROUTINENAME = X.SPECIFICNAME
          AND R.ROUTINESCHEMA = X.ROUTINESCHEMA)
        INNER JOIN FILTER_PARMS FP
         ON (FP.ROUTINESCHEMA  = X.ROUTINESCHEMA 
             AND FP.ROUTINENAME =  X.ROUTINENAME)
        INNER JOIN SYSCAT.PACKAGEDEP P
        ON (P1.UNIQUE_ID = P.UNIQUE_ID
        AND P.PKGNAME = R.BNAME
        AND P.PKGSCHEMA = R.ROUTINESCHEMA)
      WHERE P.BTYPE NOT IN ( 'I','F','T','S','N','U','W')
       ) 
SELECT STOREDPROC,TEXTX,OBJECTNAME,CARD,BIND_STATS_CREATE_TIME,FLAG
  FROM ROUTINEDEP
  ORDER BY SORTCOL
  WITH UR;
-----------------------------------------------------------------------
-- FLAG column show possible stats mismatch where a
-- procs bind time < stats time for Tables/Indexes
--
-- Also review CARD, which shows row counts for tables based on stats
-- is that what you expect?
--
-- Flag column also generates values clause that you can cut and paste
-- into the values clause to review called procs using this query
------------------------------------------------------------------------

And a few things Fred suggested to be mindful of... "It should work with DB2luw and has been tested in AIX v9.5-10.2. There is one major caveat. The query assumes one proc has only one specific name i.e., it only works for non-overloaded procs. It also uses at least one deprecated column, ROUTINENAME in ROUTINEDEP. Changing the proc to use specific names wouldn’t be a big deal."

Have fun, and if you use this or have any suggested enhancements, please leave a comment below.