RE: SQL Tunning - result of set autot traceonly

Firstly, you must understand that you have extracted only part of the Execution Plan.
An Execution Plan consists of
A) The Operations --- which are presented in a tabular manner B) Predicate Information for some of the operations -- which shows which predicates from the query (or transformed query) were applied at the corresponding operation

1.) oracle ran the query from 4 to 25 or it ran from 25 to 4 Without knowing the execution plan, we can't really see which step was executed first and which was executed next and so on. These numbers are operation IDs -- it doesn't necessarily mean that it the actual execution was in the same sequence as these IDs.

2.) What does it mean : 'access'
That the rows retrieved by applying this predicate. In general, rows may be accessed via an Index or a FullTableScan

 3.) What does it mean : 'filter'
That rows retrieved from the preceding step in the execution plan were filtered. Rows are filtered to eliminate those that do not meet the query requirements

4.) Considering that the item 21 is more selective for query, where must I put it in the statment:
It doesn't matter where you put it. In theory, the optimizer should be able to optimize or rewrite the query.
Also, remember that, in some/many cases, you might know more than the optimizer --- the simplest reason being that the table/column/index statistics last gathered don't reflect the current nature of the data, or for more complex reasons such as dependencies between columns etc

Hemant K Chitale

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Eriovaldo Andrietta Sent: Tuesday, July 12, 2011 7:40 AM
To: ORACLE-L
Subject: SQL Tunning - result of set autot traceonly

Hi Friends,

  I have the Result from traceonly, as below.   My doubt is:

   1.) oracle ran the query from 4 to 25 or it ran from 25 to 4

   2.) What does it mean : 'access'

        Means that the oracle process went to the disk to retrieve data ?

   3.) What does it mean : 'filter'

        Means that oracle process performed a filter in the data that was in memory (cached) ?

   4.) Considering that the item 21 is more selective for query, where must I put it in the statment:

        at the begin of the WHERE CLAUSE or
        at the eng of the WHERE CLAUSE ?

Predicate Information (identified by operation id):

   4 - access("T1"."NUM_DOCUMENTO"="SPL"."NUM_DOCUMENTO" AND "SPL"."NUM_ACIONAMENTO"="VW_COL_1")    5 - access("NUM_DOCUMENTO"="T1"."NUM_DOCUMENTO")

   9 - filter("T1"."UF"='XX')

  10 - access(ROWID=ROWID)

  11 - access(ROWID=ROWID)

  12 - access(ROWID=ROWID)

  13 - access(ROWID=ROWID)

  14 - access(ROWID=ROWID)

  15 - access("T1"."UF"='RS')

  21 - filter("SPL"."STATUS"=2 AND "SPL"."DATA">=TO_DATE(' 2003-12-19 00:00:00', 'syyyy-mm-dd

              hh24:mi:ss') AND "SPL"."DATA"<=TO_DATE(' 2011-07-06 00:00:00', 'syyyy-mm-dd hh24:mi:ss'))

  23 - access("T1"."NUM_DOCUMENTO"="SC"."NUM_DOCUMENTO"(+))

  24 - filter("TC"."N1"='BRT')

  25 - access("T1"."NUM_DOCUMENTO"="TC"."NUM_DOCUMENTO")

Regards
Eriovaldo

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