Create index is taking more time

Question

Hi,
One of the concurrent program is taking more time , We generate the trace file and found that the create index is taking more time.
Below is from the trace file and such type of index creation is happening lot of time in Oracle standard program.
Can somebody let me know why there is a big difference between cpu and elapse time.
We are seeing the PX Deq: Execute Reply Event as well.look idle time for database.
Please let me know which parameter of the database is affecting this.
CREATE INDEX ITEM_CATEGORIES_N2_BD9 ON ITEM_CATEGORIES_BD9(CATEGORY_SET_ID,
SR_CATEGORY_ID,ORGANIZATION_ID,SR_INSTANCE_ID) PARALLEL TABLESPACE MSCX
STORAGE( INITIAL 40960 NEXT 33554432 PCTINCREASE 0) PCTFREE 10 INITRANS 11
MAXTRANS 255
call count cpu elapsed disk query current rows
Parse 1 0.00 0.00 0 3 0 0
Execute 1 0.35 364.82 131168 117945 60324 0
Fetch 0 0.00 0.00 0 0 0 0
total 2 0.35 364.83 131168 117948 60324 0
Misses in library cache during parse: 1
Optimizer mode: ALL_ROWS
Parsing user id: 80 (recursive depth: 2)
Elapsed times include waiting on following events:
Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
reliable message 1 0.00 0.00
enq: KO - fast object checkpoint 1 0.01 0.01
PX Deq: Join ACK 6 0.00 0.00
PX Deq Credit: send blkd 112 0.00 0.01
PX qref latch 7 0.00 0.00
PX Deq: Parse Reply 3 0.00 0.00
PX Deq: Execute Reply 604 1.96 364.42
log file sync 1 0.00 0.00
PX Deq: Signal ACK 1 0.00 0.00
latch: session allocation 2 0.00 0.00
Regards,

Answer 1

user12121524 wrote:
CREATE  INDEX ITEM_CATEGORIES_N2_BD9 ON ITEM_CATEGORIES_BD9(CATEGORY_SET_ID,
SR_CATEGORY_ID,ORGANIZATION_ID,SR_INSTANCE_ID) PARALLEL  TABLESPACE MSCX
STORAGE(  INITIAL 40960 NEXT 33554432 PCTINCREASE 0) PCTFREE 10 INITRANS 11
MAXTRANS 255
call     count       cpu    elapsed       disk      query    current        rows
Parse        1      0.00       0.00          0          3          0           0
Execute      1      0.35     364.82     131168     117945      60324           0
Fetch        0      0.00       0.00          0          0          0           0
total        2      0.35     364.83     131168     117948      60324           0
Misses in library cache during parse: 1
Optimizer mode: ALL_ROWS
Parsing user id: 80     (recursive depth: 2)
Elapsed times include waiting on following events:
Event waited on                             Times   Max. Wait  Total Waited
----------------------------------------   Waited  ----------  ------------
reliable message                                1        0.00          0.00
enq: KO - fast object checkpoint                1        0.01          0.01
PX Deq: Join ACK                                6        0.00          0.00
PX Deq Credit: send blkd                      112        0.00          0.01
PX qref latch                                   7        0.00          0.00
PX Deq: Parse Reply                             3        0.00          0.00
PX Deq: Execute Reply                         604        1.96        364.42
log file sync                                   1        0.00          0.00
PX Deq: Signal ACK                              1        0.00          0.00
latch: session allocation                       2        0.00          0.00
What you've given us is the query co-ordinator trace, which basically tells us that the the coordinator waited 364 seconds for the PX slaves to tell it that they had completed their tasks ("PX Deq: Execute Reply" time). You need to look at the slave traces to find out where they spent their time - and that's probably not going to be easy if there are lots of parallel pieces of processing going on.
If you want to do some debugging (in general) one option is to add a query against V$pq_tqstat after each piece of parallel processing and log the results to a named file, or write them to a table with a tag, as this will tell you how many slaves were involved, how, and what the distribution of work and time was.
Regards
Jonathan Lewis
http://jonathanlewis.wordpress.com
http://www.jlcomp.demon.co.uk
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