Re: explain

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От Popeanga Marian
Тема Re: explain
Дата
Msg-id 3E7BFE7F.2010500@cnlo.ro
обсуждение исходный текст
Ответ на Re: explain  (<mallah@trade-india.com>)
Ответы Re: explain  (Rajesh Kumar Mallah <mallah@trade-india.com>)
Список pgsql-sql
Mallah,

       Thanks for your info,
       I runned the query with explain yesterday and it didn't work for 
a user where i didn't had enough privileges i think !?    
Why db didn't say anythink  ?

I created a new user and a new table.
    Explain for this table worked just as you said and for any other 
querys.

Is there any way to know if a user has wright privileges to explain a 
query ?

mallah@trade-india.com wrote:

>Popeanga  ,
>
>Its basically possible to get the info programatically.
>see below is an example perl code that is getting the
>plan data:
>
>############### file test.pl #################
>
>#!/usr/bin/perl
>
>use DBI;
>$dbh = DBI->connect('dbi:Pg:dbname=rmallah' , '','');
>$your_query_here= 'select * from test';
>$rows = $dbh -> selectall_arrayref("EXPLAIN ANALYZE $your_query_here");
>foreach (@$rows) {
>        print "$_->[0]\n";
>}
>$dbh -> disconnect();
>#############################################
>
>on running you get:
>
>[rmallah@subho rmallah]$ ./test.pl
>Seq Scan on test  (cost=0.00..20.00 rows=1000 width=32) (actual time=0.02..0.05 rows=11 loops=1)
>Total runtime: 0.19 msec
>
>But be careful abt explain analyzing
>queries that potentially modify data. (read more on docs of EXPLAIN)
>we have to put the explain analyze in a transaction block which
>shud eventually be rollbacked.
>
>now that you have seen how to get lines of output from EXPLAIN using/hadling this
>data is upto you application.
>
>also note that the last like of EXPLAIN analyze carries  the runtime.
>
>hope it helps
>Mallah.
>
>
>
>
>
>
>-----------------------------------------
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>
>
>  
>

-- 
Popeanga Marian
DBA Oracle
CNLO Romania



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