Re: explain

From: Popeanga Marian <pmarian(at)cnlo(dot)ro>
To: mallah(at)trade-india(dot)com
Cc: pgsql-sql(at)postgresql(dot)org
Subject: Re: explain
Date: 2003-03-22 06:11:11
Message-ID: 3E7BFE7F.2010500@cnlo.ro
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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(at)trade-india(dot)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(at)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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  • Re: explain at 2003-03-22 08:45:02 from Rajesh Kumar Mallah

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