Re: Wow - has anyone used ROW_NUMBER() to get around using a UNION statement when UNION ALL doesn't work??

From: Taylor, Chris David <ChrisDavid.Taylor_at_ingrambarge.com>
Date: Sat, 6 Aug 2011 07:14:48 -0500
Message-ID: <5729F097-A03F-4658-B466-399FCCA6ABDD_at_ingrambarge.com>

IGNORE THIS. This hit the list way way late. I sent it yesterday morning.

Sent from my mobile device. Please ignore any typos or misspellings.

On Aug 6, 2011, at 7:05 AM, "Taylor, Chris David" <ChrisDavid.Taylor_at_ingrambarge.com<mailto:ChrisDavid.Taylor_at_ingrambarge.com>> wrote:

My bad…appears it is a SORT UNIQUE.

Some info for the UNION statement for those interested.

all count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------

Parse        1      0.01       0.01          0          0          0           0
Execute      1      0.65       0.67          0          0          0           0
Fetch     5994   1057.75    1107.17     810969  113249228          0       89887


------- ------  -------- ---------- ---------- ---------- ----------  ----------


total     5996   1058.42    1107.86     810969  113249228          0       89887

Misses in library cache during parse: 1 Optimizer mode: ALL_ROWS
Parsing user id: 40 (TAYLORCD)

Rows Row Source Operation
------- ---------------------------------------------------
89887 SORT UNIQUE (cr=113249228 pr=810969 pw=626505 time=493052784 us) 55660314 UNION-ALL (cr=113249228 pr=810969 pw=626505 time=1072529374 us) 55638945 FILTER (cr=112930742 pr=627121 pw=626460 time=849610294 us)

55638945     NESTED LOOPS OUTER (cr=112930742 pr=627121 pw=626460 time=793971330 us)
55638945      HASH JOIN OUTER (cr=1620540 pr=627107 pw=626460 time=237581831 us)
55638945       HASH JOIN  (cr=1620291 pr=647 pw=0 time=71036269 us)
168038        NESTED LOOPS  (cr=1620128 pr=647 pw=0 time=13021563 us)
168074         NESTED LOOPS  (cr=1115868 pr=612 pw=0 time=11175307 us)
170294          NESTED LOOPS  (cr=571996 pr=156 pw=0 time=5009839 us)
176499           HASH JOIN  (cr=41639 pr=68 pw=0 time=1099154 us)
  86158            TABLE ACCESS FULL PS_PO_LINE_DISTRIB (cr=41476 pr=68 pw=0 time=517091 us)
  12127            INDEX FAST FULL SCAN PS_ING_BARGESPECIF (cr=163 pr=0 pw=0 time=12283 us)(object id 252516)
170294           TABLE ACCESS BY INDEX ROWID PS_RECV_LN_SHIP (cr=530357 pr=88 pw=0 time=4124289 us)
176615            INDEX RANGE SCAN PSARECV_LN_SHIP (cr=353813 pr=18 pw=0 time=2363954 us)(object id 146221)
168074          TABLE ACCESS BY INDEX ROWID PS_VOUCHER_LINE (cr=543872 pr=456 pw=0 time=6177518 us)
202880           INDEX RANGE SCAN PSCVOUCHER_LINE (cr=341256 pr=17 pw=0 time=2063029 us)(object id 3415975)
168038         TABLE ACCESS BY INDEX ROWID PS_PO_HDR (cr=504260 pr=35 pw=0 time=2990556 us)
168074          INDEX UNIQUE SCAN PS_PO_HDR (cr=336150 pr=14 pw=0 time=1497933 us)(object id 254380)
  12127        INDEX FAST FULL SCAN PS_ING_BARGESPECIF (cr=163 pr=0 pw=0 time=24348 us)(object id 252516)
  14543       INDEX FAST FULL SCAN PSAVENDOR (cr=249 pr=0 pw=0 time=159 us)(object id 294592)
55638945      INDEX RANGE SCAN PSJVOUCHER (cr=111310202 pr=14 pw=0 time=457216175 us)(object id 7430349)
  21369    HASH GROUP BY (cr=318486 pr=183848 pw=45 time=23546310 us)
  21570     FILTER  (cr=318486 pr=183803 pw=0 time=23499224 us)
  21570      HASH JOIN  (cr=318486 pr=183803 pw=0 time=23477629 us)
  21570       NESTED LOOPS  (cr=318242 pr=183803 pw=0 time=23234968 us)
  21799        NESTED LOOPS  (cr=252843 pr=183720 pw=0 time=29737359 us)
  21701         HASH JOIN  (cr=187611 pr=183197 pw=0 time=19122601 us)
   6184          SORT UNIQUE (cr=163 pr=0 pw=0 time=10305 us)
  12127           INDEX FAST FULL SCAN PS_ING_BARGESPECIF (cr=163 pr=0 pw=0 time=112 us)(object id 252516)
  27191          TABLE ACCESS FULL PS_DISTRIB_LINE (cr=187448 pr=183197 pw=0 time=22200559 us)
  21799         TABLE ACCESS BY INDEX ROWID PS_VOUCHER_LINE (cr=65232 pr=523 pw=0 time=3169056 us)
  21799          INDEX RANGE SCAN PS_VOUCHER_LINE (cr=43518 pr=139 pw=0 time=1077691 us)(object id 4760299)
  21570        TABLE ACCESS BY INDEX ROWID PS_VOUCHER (cr=65399 pr=83 pw=0 time=859260 us)
  21799         INDEX UNIQUE SCAN PS_VOUCHER (cr=43600 pr=65 pw=0 time=535339 us)(object id 257125)
  14543       INDEX FAST FULL SCAN PS0VENDOR (cr=244 pr=0 pw=0 time=82 us)(object id 154642)

Elapsed times include waiting on following events:
  Event waited on                             Times   Max. Wait  Total Waited
  ----------------------------------------   Waited  ----------  ------------
  SQL*Net message to client                    5994        0.00          0.01
  db file sequential read                      1459        0.21          7.08
  direct path write temp                      41767        0.38         13.77
  latch free                                      1        0.00          0.00
  direct path read temp                       41767        0.59         11.49
  db file scattered read                       4126        0.03         14.94
  latch: library cache                            3        0.00          0.00
  SQL*Net message from client                  5994       19.73        363.35
********************************************************************************

Chris Taylor
Sr. Oracle DBA
Ingram Barge Company
Nashville, TN 37205
Office: 615-517-3355
Cell: 615-663-1673
Email: <mailto:chris.taylor_at_ingrambarge.com> chris.taylor_at_ingrambarge.com<mailto:chris.taylor_at_ingrambarge.com>

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From: Wolfgang Breitling [mailto:breitliw_at_centrexcc.com] Sent: Friday, August 05, 2011 1:52 PM
To: Taylor, Chris David
Cc: 'oracle-l_at_freelists.org<mailto:oracle-l_at_freelists.org>' Subject: Re: Wow - has anyone used ROW_NUMBER() to get around using a UNION statement when UNION ALL doesn't work??

What Oracle version?
Is the UNION using a sort or a "HASH UNIQUE"?

On 2011-08-05, at 12:35 PM, Taylor, Chris David wrote:

I’ve got a query that uses a UNION statement to join 2 large data sets.

When I run the statement it takes 20 minutes to execute (using UNION), returns 89,887 rows and consumes 5GB of TEMP tablespace.

Now, I changed it to a UNION ALL statement to see what I have and I get 89,963 rows (too many), 2 minutes to execute and 0 TEMP tablespace. (I know there’s some caching going on here as well but we’ll ignore that for the moment.)

Now, I put the query containing the UNION ALL in an INNER select, and I select all columns from it PLUS the ROW_NUMBER() function partitioning by all the columns and applying an order by to the function and call this column “ROW_KEY” (not very original I know).

Finally, I wrap that query into another subselect and this type I append a where clause to the outside “WHERE ROW_KEY = 1”.

Now, I get my correct 89,887 rows in right at 2 minutes and 0 TEMP tablespace (again some caching here I’m sure).

I’m curious if anyone has tried this before, or if it is of interest to anyone.

I have a pretty good test case we could play with if anyone is interested? (I also have plenty of trace files etc)

--

http://www.freelists.org/webpage/oracle-l Received on Sat Aug 06 2011 - 07:14:48 CDT

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