Re: explain

Ok i'll try to explain you in detail what i am trying to accomplish.<br /><br /> I am working at a cross platform tool
foradministration (and many more ) of Oracle , Postgresql, MySql<br /><a class="moz-txt-link-freetext"
href="http://cptd-proj.sourceforge.net">http://cptd-proj.sourceforge.net</a><br/><br />        I don't have many
knowledgeas a postgresql user or dba.  I have worked with Oracle mainly.<br /><br /><br /> In Oracle explain plans are
storedinto a special table named PLAN_TABLE so when i issue<br /><pre wrap="">explain plan set
statement_id=uniq_id_for_selectfor                 select * from dba_tables where table_name=:tab         
 
</pre> <pre wrap=""></pre><br /> new entrys with the explain plan are inserted into this special table.<br /> And you
canselect those entrys from this PLAN_TABLE and show it into a widget. <br /><br /><pre wrap="">SELECT * FROM
plan_tableWHERE Statement_ID = uniq_id_for_select</pre><br /> Now the issue i encounter is that i want to show the
excutionplan for connections against PostgreSql DB too, but i don't know from where to find this information.<br /> I
noticedthat pgsql is able to explain plan for selects.<br /><br />  But how ?<br /><br /><br /> Rajesh Kumar Mallah
wrote:<br/><blockquote cite="mid200303211740.27016.mallah@trade-india.com" type="cite"><pre wrap="">
 
Hi,


Marian i am not too familiar with oracle features.

Can you tell us the problem you are trying to solve.

lemme try to understand the below.
 </pre><blockquote type="cite"><blockquote type="cite"><pre wrap="">In Oracle i will do:
explain plan set statement_id=uniq_id_for_select for                 select * from dba_tables where table_name=:tab
</pre></blockquote></blockquote><prewrap="">
 

what does it do ?
assigning a uniq_id to the query "select * from dba_tables where table_name=:tab"
is the query an example query or a fixed method of accomplising something?

 </pre><blockquote type="cite"><blockquote type="cite"><pre wrap="">SELECT * FROM plan_table WHERE Statement_ID =
this_uniq_id_for_select;
     </pre></blockquote></blockquote><pre wrap="">
is plan_table supposed to store execution plans of all the  queries being
executed by dbserver , or only certain queries you are marking by 
some mechanism?

In case you are wanting to see the execution plan and query times of each and every
query there is a crude method.

(DISCLAIMER: the opinions are mine and does not reflects others')

enable logging to appropriate levels , postmaster can log execution plans
and timings in a file.
you will find more details in Admin Docs.

Regds
mallah.



On Friday 21 Mar 2003 4:30 pm, Popeanga Marian wrote: </pre><blockquote type="cite"><pre wrap="">
Popeanga Marian wrote:
   </pre><blockquote type="cite"><pre wrap="">Thanks for your repply.
       This is what i expected too.  Can you point me from where i 
can get this result ?

explain select * from pg_tables where tablename=:tab;


select * from ... ?




     </pre></blockquote><pre wrap="">I need this at programming level, not from within pgsql tool.
I tryed directly with explain select ... but it doesn't retrive any tuples!
   </pre><blockquote type="cite"><pre wrap="">Rajesh Kumar Mallah wrote:
     </pre><blockquote type="cite"><pre wrap="">Dear Marian,

in postgresql 7.3 explain commands retruns as
set of rows.

The result of EXPLAIN can just be fecthed as result
of any other SELECT query and manipulated further.

i hope it helps.

sorry if i did not get ur problem rite.


regds
mallah.




On Friday 21 Mar 2003 11:51 am, Popeanga Marian wrote:
       </pre><blockquote type="cite"><pre wrap="">Roberto Mello wrote:
  
         </pre><blockquote type="cite"><pre wrap="">On Fri, Mar 21, 2003 at 07:46:01AM +0200, Popeanga Marian wrote:

    
           </pre><blockquote type="cite"><pre wrap="">Hello all,

        Can someone point me how can i make explain plan for a query? 
      
             </pre></blockquote><pre wrap="">explain select blah from foo where bar = baz;

\h explain

Look at the PostgreSQL documentation (SQL Reference).

-Roberto


    
           </pre></blockquote><pre wrap="">  I have look at this command. I want to know how can i make this from 
other tool than pgsql.
In oracle when i issue an explain plan the explain insert values into a 
table ( plan_table ).
Then i could select the values from plan_table.         Is there similar 
in postgres ?

-- 
Popeanga Marian
DBA Oracle
CNLO Romania


  
         </pre></blockquote><pre wrap=""> 
       </pre></blockquote><pre wrap="">-- 
Popeanga Marian
DBA Oracle
CNLO Romania

     </pre></blockquote><pre wrap="">-- 
Popeanga Marian
DBA Oracle
CNLO Romania


   </pre></blockquote><pre wrap=""> </pre></blockquote><br /><pre class="moz-signature" cols="$mailwrapcol">-- 
Popeanga Marian
DBA Oracle
CNLO Romania
</pre><br />