Re: Trying to track down weird query stalls

From: dan@sidhe.org
Subject: Re: Trying to track down weird query stalls
Date: ,
Msg-id: 51413.199.172.169.17.1238447256.squirrel@localhost
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In response to: Re: Trying to track down weird query stalls  (Alvaro Herrera)
Responses: Re: Trying to track down weird query stalls  (Alvaro Herrera)
List: pgsql-performance

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Trying to track down weird query stalls  (, )
 Re: Trying to track down weird query stalls  (Robert Haas, )
  Re: Trying to track down weird query stalls  (, )
   Re: Trying to track down weird query stalls  (Robert Haas, )
    Re: Trying to track down weird query stalls  (, )
   Re: Trying to track down weird query stalls  (Scott Marlowe, )
 Re: Trying to track down weird query stalls  (, )
  Re: Trying to track down weird query stalls  (Scott Marlowe, )
   Re: Trying to track down weird query stalls  (, )
    Re: Trying to track down weird query stalls  (Robert Haas, )
     Re: Trying to track down weird query stalls  (, )
      Re: Trying to track down weird query stalls  (Alvaro Herrera, )
       Re: Trying to track down weird query stalls  (, )
        Re: Trying to track down weird query stalls  (Alvaro Herrera, )
         Re: Trying to track down weird query stalls  (, )
          Re: Trying to track down weird query stalls  (Alvaro Herrera, )
           Re: Trying to track down weird query stalls  (, )
            Re: Trying to track down weird query stalls  (Alvaro Herrera, )
            Re: Trying to track down weird query stalls  (Scott Carey, )

>  escribió:
>> >  escribió:
>> >
>> >> where libinstance.libdate <= 1238445044
>> >>    and libinstance.enddate > 1238445044
>> >>    and libinstance.libinstanceid = libobject.libinstanceid
>> >>    and libinstance.architecture = ?
>> >
>> > How are you generating the explain?  My bet is that you're just
>> > substituting a literal in the architecture condition, but if the
>> driver
>> > is smart then maybe it's preparating the query beforehand.  You'll get
>> a
>> > different plan in that case.
>>
>> I don't think so. Perl's DBI is involved, but the statement's in a
>> variable.
>
> So what's the "?" in the query you pasted earlier?

The first ? (for architecture) is 1, the second ? (for branchid) is 0.
They both should get passed to Postgres as $1 and $2, respectively,
assuming DBD::Pg does its substitution right. (They're both supposed to go
in as placeholders)

-Dan


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From: Scott Carey
Date:
Subject: Re: Trying to track down weird query stalls
From: Matthew Wakeling
Date:
Subject: Re: Very specialised query