Re: Estimating a PK index rebuild with REVERSE

  • From: Martin Berger <martin.a.berger@xxxxxxxxx>
  • To: Lothar Flatz <l.flatz@xxxxxxxxxx>
  • Date: Thu, 26 Oct 2017 18:42:40 +0200

to avoid  ORA-01408 <01%20408> you can always create an interim index with
additional "column" with the number 1.
then the creation of your target-index will be faster, as this interim
index is used.

not a beautiful, but practical solution.

2017-10-26 10:33 GMT+02:00 Lothar Flatz <l.flatz@xxxxxxxxxx>:

Too bad you are not on 12c.
I wonder if You could create the new index invisible to avoid ORA-01408
<01%20408>.
Disable the constraint, drop the old index, make the new index visible and
reanable the constraint.
(At least I think it works, I have never tried.)


Am 25.10.2017 um 21:58 schrieb Andy Sayer:

Using the online clause of the create index statement will force the table
to be read instead.

Regards,
Andrew

On Wed, 25 Oct 2017 at 20:54, Luis Santos <lsantos@xxxxxxxxx> wrote:

Ok, it's here. First our DB version and PSU.


[11g]> @psu
COMMENTS                                           VERSION

--------------------------------------------------
------------------------------
PSU 11.2.0.4.170814                                11.2.0.4




Note that I tried to use hints on CREATE INDEX command. Look the article:
https://blog.pythian.com/oracles-create-index-command-can-take-hint

But they did not work.


​​
[11g]> explain plan for
  2   CREATE /*+ NO_INDEX(L PK_TABLE_NAME1) FULL(L) */ UNIQUE INDEX
 "OWNER_O"."PK_TABLE_NAME1" ON "OWNER_O"."TABLE_NAME1" L ("ID_TABLE_NAME1",
"DATA") REVERSE
  3   PCTFREE 10 INITRANS 2 MAXTRANS 255
  4   STORAGE(
  5   BUFFER_POOL DEFAULT FLASH_CACHE DEFAULT CELL_FLASH_CACHE DEFAULT)
  6   TABLESPACE "CRIVO_INDEX"  LOCAL
  7   parallel 64
  8  /
Explicado.
U71013576@P01CRV.brux0387 [11g]> @xplan
PLAN_TABLE_OUTPUT
------------------------------------------------------------
------------------------------------------------------------
------------------------------------------------------------

Plan hash value: 961639110
------------------------------------------------------------
------------------------------------------------------------
---------------------
| Id  | Operation                     | Name           | Rows  | Bytes |
Cost (%CPU)| Time     | Pstart| Pstop |    TQ  |IN-OUT| PQ Distrib |
------------------------------------------------------------
------------------------------------------------------------
---------------------
|   0 | CREATE INDEX STATEMENT        |                |  7462M|   111G|
  292K  (1)| 00:58:27 |       |       |        |      |            |
|   1 |  PX COORDINATOR               |                |       |       |
           |          |       |       |        |      |            |
|   2 |   PX SEND QC (RANDOM)         | :TQ10000       |  7462M|   111G|
           |          |       |       |  Q1,00 | P->S | QC (RAND)  |
|   3 |    PX PARTITION RANGE ALL     |                |  7462M|   111G|
           |          |     1 |    28 |  Q1,00 | PCWC |            |

|   4 |     INDEX BUILD UNIQUE (LOCAL)| PK_TABLE_NAME1 |       |       |
           |          |     1 |    28 |  Q1,00 | PCWP |            |

|   5 |      SORT CREATE INDEX        |                |  7462M|   111G|
           |          |       |       |  Q1,00 | PCWP |            |

|   6 |       INDEX FAST FULL SCAN    | PK_TABLE_NAME1 |  7462M|   111G|
  124K  (1)| 00:24:58 |     1 |    28 |  Q1,00 | PCWP |            |

------------------------------------------------------------
------------------------------------------------------------
---------------------
Query Block Name / Object Alias (identified by operation id):
-------------------------------------------------------------
   1 - CRI$1

   6 - CRI$1 / L@CRI$1


Column Projection Information (identified by operation id):
-----------------------------------------------------------
   1 - SYSDEF[272], SYSDEF[4]
   2 - (#keys=0) SYSDEF[272], SYSDEF[4]
   3 - SYSDEF[272], SYSDEF[4]
   4 - SYSDEF[272]

   5 - (#keys=2) REVERSE("ID_TABLE_NAME1")[22], REVERSE("DATA")[7],
"L".ROWID[ROWID,10]
   6 - "L".ROWID[ROWID,10], "ID_TABLE_NAME1"[NUMBER,22], "DATA"[DATE,7]


Note
-----
   - estimated index size: 225G bytes



*--*
*Att*


*Luis Santos *


2017-10-25 12:32 GMT-02:00 Mark W. Farnham <mwf@xxxxxxxx>:

Would you add the actual SQL text you submitted?



mwf



*From:* oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@
freelists.org] *On Behalf Of *Luis Santos
*Sent:* Wednesday, October 25, 2017 10:10 AM
*To:* ORACLE-L
*Subject:* Estimating a PK index rebuild with REVERSE



Hi Oracle-L,



I'm trying to estimate the time necessary to recreate a PK index with
the reverse clause. Usually I use explain plan to estimate time and size
for a new index.



I did a reverse script from the actual PK index using and DBMS_METADATA
and issued the explain plan, adding the reverse clause.



It worked nicely, and the output was.





[11g]> @xplan
PLAN_TABLE_OUTPUT
------------------------------------------------------------
------------------------------------------------------------
---------------------------
Plan hash value: 961639110
------------------------------------------------------------
------------------------------------------------------------
---------------------
| Id  | Operation                     | Name           | Rows  | Bytes |
Cost (%CPU)| Time     | Pstart| Pstop |    TQ  |IN-OUT| PQ Distrib |
------------------------------------------------------------
------------------------------------------------------------
---------------------
|   0 | CREATE INDEX STATEMENT        |                |  7462M|   111G|
  292K  (1)| 00:58:27 |       |       |        |      |            |
|   1 |  PX COORDINATOR               |                |       |       |
           |          |       |       |        |      |            |
|   2 |   PX SEND QC (RANDOM)         | :TQ10000       |  7462M|   111G|
           |          |       |       |  Q1,00 | P->S | QC (RAND)  |
|   3 |    PX PARTITION RANGE ALL     |                |  7462M|   111G|
           |          |     1 |    28 |  Q1,00 | PCWC |            |
|   4 |     INDEX BUILD UNIQUE (LOCAL)| PK_TABLE_DATA1 |       |       |
           |          |     1 |    28 |  Q1,00 | PCWP |            |
|   5 |      SORT CREATE INDEX        |                |  7462M|   111G|
           |          |       |       |  Q1,00 | PCWP |            |
|   6 |       INDEX FAST FULL SCAN    | PK_TABLE_DATA1 |  7462M|   111G|
  124K  (1)| 00:24:58 |     1 |    28 |  Q1,00 | PCWP |            |
------------------------------------------------------------
------------------------------------------------------------
---------------------
Query Block Name / Object Alias (identified by operation id):
-------------------------------------------------------------
   1 - CRI$1
   6 - CRI$1 / TABLE_DATA1@CRI$1
Column Projection Information (identified by operation id):
-----------------------------------------------------------
   1 - SYSDEF[272], SYSDEF[4]
   2 - (#keys=0) SYSDEF[272], SYSDEF[4]
   3 - SYSDEF[272], SYSDEF[4]
   4 - SYSDEF[272]
   5 - (#keys=2) REVERSE("ID_TABLE_DATA1")[22], REVERSE("DATA")[7],
"TABLE_DATA1".ROWID[ROWID,10]
   6 - "TABLE_DATA1".ROWID[ROWID,10], "ID_TABLE_DATA1"[NUMBER,22],
"DATA"[DATE,7]
Note
-----
   - estimated index size: 225G bytes



But this is the evaluation phase. The PK was not, of course, already
dropped. So the actual non reverse PK index is been used in the create
index plan...





How can I disable the access to the actual PK for this explain plan?





Best regards,

*Luis Santos*



--








-- 
Martin Berger         +43 660 2978929 <+436602978929>
martin.a.berger@xxxxxxxxx @martinberx <https://twitter.com/martinberx>
^∆x      http://berxblog.blogspot.com

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