How to "TUNE" expdp?

Question

All,
Server: Sun Solaris 10
Database: Oracle 10g (stand alone) 10.2.0.4
We are seeing one of our Batch processes running slow. During this period when it runs slow, we have extracted the AWR and ADDM reports. Below are the same for referece.
ADDM Report Highlights:*
         FINDING 1: 70% impact (70089 seconds)
PL/SQL execution consumed significant database time.
   RECOMMENDATION 1: SQL Tuning, 48% benefit (47865 seconds)
      ACTION: Tune the PL/SQL block with SQL_ID "9knuzfs7zmxmv". Refer to the
         "Tuning PL/SQL Applications" chapter of Oracle's "PL/SQL User's Guide
         and Reference"
         RELEVANT OBJECT: SQL statement with SQL_ID 9knuzfs7zmxmv
         BEGIN
         SYS.KUPW$WORKER.MAIN('SYS_EXPORT_FULL_06', 'SYS');
         END;
      RATIONALE: SQL statement with SQL_ID "9knuzfs7zmxmv" was executed 10
         times and had an average elapsed time of 5088 seconds.
      RATIONALE: Average time spent in PL/SQL execution was 4786 seconds.
   RECOMMENDATION 2: SQL Tuning, 22% benefit (22483 seconds)
      ACTION: Investigate the SQL statement with SQL_ID "59bh50fscntuj" for
         possible performance improvements.
         RELEVANT OBJECT: SQL statement with SQL_ID 59bh50fscntuj and
         PLAN_HASH 2198587470
         CREATE TABLE "ET$024BC2CC0001"
         "GUID",
         "LOGTYPE",
         "PUBDATALONG"
         ) ORGANIZATION EXTERNAL
         ( TYPE ORACLE_DATAPUMP  DEFAULT DIRECTORY DPUMP_DIR_CRON ACCESS
         PARAMETERS (DEBUG =0 DATAPUMP INTERNAL TABLE 
         "SYSADM"."PSIBLOGIBINFO"  JOB ( "SYS","SYS_EXPORT_FULL_06",1)
         WORKERID 2 PARALLEL 3 VERSION COMPATIBLE ENCRYPTPASSWORDISNULL )
         LOCATION ('bogus.dat') )  PARALLEL 3 REJECT LIMIT UNLIMITED
         AS SELECT /*+ PARALLEL(KU$,3) */ "GUID", "LOGTYPE",
         TO_LOB("PUBDATALONG")
         FROM RELATIONAL("SYSADM"."PSIBLOGIBINFO" ) KU$
      RATIONALE: SQL statement with SQL_ID "59bh50fscntuj" was executed 1
         times and had an average elapsed time of 22483 seconds.
      RATIONALE: At least one execution of the statement ran in parallel.
      RATIONALE: Average time spent in PL/SQL execution was 22224 seconds.
AWR Report Findings:*
WORKLOAD REPOSITORY report for
DB Name         DB Id    Instance     Inst Num Release     RAC Host       
HR8PRD         254316722 hr8prd              1 10.2.0.4.0  NO  uxhrpr53   
              Snap Id      Snap Time      Sessions Curs/Sess
Begin Snap:     34023 25-Jan-13 01:01:02       306       4.2
  End Snap:     34026 25-Jan-13 04:00:10       306       4.1
   Elapsed:              179.13 (mins)
   DB Time:            1,666.75 (mins)
Cache Sizes
~~~~~~~~~~~                       Begin        End
               Buffer Cache:    18,480M    18,480M  Std Block Size:         8K
           Shared Pool Size:     3,840M     3,840M      Log Buffer:    10,320K
Load Profile
~~~~~~~~~~~~                            Per Second       Per Transaction
                  Redo size:            384,182.98            139,221.48
              Logical reads:             67,752.53             24,552.38
              Block changes:              7,210.41              2,612.93
             Physical reads:              8,507.25              3,082.89
            Physical writes:                 72.47                 26.26
                 User calls:              1,365.84                494.96
                     Parses:                 71.19                 25.80
                Hard parses:                  2.36                  0.86
                      Sorts:                176.16                 63.84
                     Logons:                  0.09                  0.03
                   Executes:                891.55                323.08
               Transactions:                  2.76
  % Blocks changed per Read:   10.64    Recursive Call %:    39.52
Rollback per transaction %:    4.06       Rows per Sort:    12.92
Instance Efficiency Percentages (Target 100%)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            Buffer Nowait %:   99.99       Redo NoWait %:  100.00
            Buffer  Hit   %:   97.25    In-memory Sort %:  100.00
            Library Hit   %:   99.14        Soft Parse %:   96.68
         Execute to Parse %:   92.02         Latch Hit %:   98.84
Parse CPU to Parse Elapsd %:             % Non-Parse CPU:  100.00
Shared Pool Statistics        Begin    End
             Memory Usage %:   66.41   47.09
    % SQL with executions>1:   96.90   89.42
  % Memory for SQL w/exec>1:   97.06   92.53
Top 5 Timed Events                                         Avg %Total
~~~~~~~~~~~~~~~~~~                                        wait   Call
Event                                 Waits    Time (s)   (ms)   Time Wait Class
CPU time                                          2,843           2.8          
enq: KO - fast object checkpoi        1,594         810    508    0.8 Applicatio
log file sync                        12,011         152     13    0.2     Commit
Streams AQ: qmn coordinator wa            1           5   5000    0.0      Other
cursor: pin S wait on X                 533           5      9    0.0 Concurrenc
          -------------------------------------------------------------       Looks like ADDM is asking for tuning the EXPDP job itself !! The AWR report however shows some bottlenecks in log file sync and streams. I also believe the streams wait event is because of EXPDP itself.
Command used to take EXPDP is as under:
expdp userid=\"/ as sysdba\" directory=dpump_dir_cron full=y dumpfile=$expname logfile=$logexpname parallel=10 filesize=50GPlease advice.
Thanks,
Suddhasatwa

Answer 1

Parallelism is always good as long as you have enough processes and cpu resources. The settings for certain initialization parameters can affect the performance of Data Pump Export and Import. In particular, you can try using the following settings to improve performance, although the effect may not be the same on all platforms.
DISK_ASYNCH_IO=TRUE
DB_BLOCK_CHECKING=FALSE
DB_BLOCK_CHECKSUM=FALSE
Additionally, the following initialization parameters must have values set high enough to allow for maximum parallelism:
PROCESSES
SESSIONS
PARALLEL_MAX_SERVERS
FOR PARALLELISM ORACLE SAYS
Set the degree of parallelism to two times the number of CPUs, then tune from there. For Data Pump Export, the PARALLEL parameter value should be less than or equal to the number of dump files. For Data Pump Import, the PARALLEL parameter value should not be much larger than the number of files in the dump file set. A PARALLEL greater than one is only available in Enterprise Edition
Edited by: Karan on Jan 25, 2013 3:59 PM