Re: a explain plan question

Hi Bernard

In the execution plan it shows this:

|   4 |    PARTITION RANGE ITERATOR|               |       |       |
|   KEY |   KEY |
|*  5 |     TABLE ACCESS FULL      | TUH_NVPAGINA  |  5992K|   211M| 27159
|   KEY |   KEY |

Since in the parse time the partition key cannot be determined we see the
KEY words. I think it basically means tabla access full by partition.




On 1/31/07, Polarski, Bernard <Bernard.Polarski@xxxxxxxxxxxxxx> wrote:


 Still I don't understand why we have a PARTITION RAND followed by a full
table scan. Why not a direct full table scan, what is the advantage of this
construct



>    4    2       PARTITION RANGE (ITERATOR)
>    5    4         TABLE ACCESS (FULL) OF 'TUH_NVPAGINA' (Cost=27159

 "

On 1/30/07, *LS Cheng* < exriscer@xxxxxxxxx> wrote:


TUD_FEDIA is accessed first then from that it eliminates partitions
(partition start/stop KEY), the problem seems nested loop, how many rows is
TU_FEDIA returning?
"



I don't see the keyword(stop key) in the plan. I read this plan and its
only speak of a partition range access that leads to a full table scan.

My only explanation is that the CBO is underlining a failed partition
pruning.



*Bernard Polarski*
  ------------------------------

*From:* amonte [mailto:ax.mount@xxxxxxxxx]
*Sent:* woensdag 31 januari 2007 10:09
*To:* oracle-l@xxxxxxxxxxxxx
*Subject:* Re: a explain plan question



You are correct, the NL is not good, I changed to hash join and the query
runs in 50 minutes.

Thanks

Alex


 On 1/30/07, *LS Cheng* < exriscer@xxxxxxxxx> wrote:

doesnt look very good plan

TUD_FEDIA is accessed first then from that it eliminates partitions
(partition start/stop KEY), the problem seems nested loop, how many rows is
TU_FEDIA returning?



  On 1/30/07, *Remigiusz Soko?owski* < rems@xxxxxxxx> wrote:


>
> Execution Plan
> ----------------------------------------------------------
>    0      SELECT STATEMENT Optimizer=CHOOSE (Cost=1022392 Card=934
> Bytes=49502)
>    1    0   SORT (GROUP BY) (Cost=1022392 Card=934 Bytes=49502)
>    2    1     NESTED LOOPS (Cost=814767 Card=182275095 Bytes=9660580035)
>    3    2       TABLE ACCESS (FULL) OF 'TUD_FEDIA' (Cost=3 Card=30
> Bytes=480)
>    4    2       PARTITION RANGE (ITERATOR)
>    5    4         TABLE ACCESS (FULL) OF 'TUH_NVPAGINA' (Cost=27159
> Card=5992606 Bytes=221726422)
>
> I was wondering how to read this plan, the order of steps. From old
> set autotrace trace exp it seems to me that step 5 is the first step?
>
>    5    4         TABLE ACCESS (FULL) OF 'TUH_NVPAGINA' (Cost=27159
> Card=5992606 Bytes=221726422)
>
AFAIK the first most nested line is the first line (in this example the
one indicated by You)

Regards
Remigiusz

--
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Remigiusz Sokolowski <rems@xxxxxxxx >
WP/PTI/DIP/ZAB (+04858) 52 15 770
MySQL  v.  4.x
Oracle v. 10.x
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