Thread: implementing query timeout

implementing query timeout

From
Jessica Perry Hekman
Date:
As has been noted on this list before, query timeouts are not implemented
in pgsql-jdbc (see

  http://archives.postgresql.org/pgsql-bugs/2000-12/msg00093.php

). This is currently causing a problem for me, and I might (no
promises) be interested in implementing it. So I'm testing the waters. If
I did submit a patch for this, would the developers here be interested?

j


Re: implementing query timeout

From
"Dave Cramer"
Date:
Jessica,

Yes we would be interested

Thanks,

Dave

-----Original Message-----
From: pgsql-jdbc-owner@postgresql.org
[mailto:pgsql-jdbc-owner@postgresql.org] On Behalf Of Jessica Perry
Hekman
Sent: Friday, March 08, 2002 5:06 PM
To: pgsql-jdbc@postgresql.org
Subject: [JDBC] implementing query timeout


As has been noted on this list before, query timeouts are not
implemented in pgsql-jdbc (see

  http://archives.postgresql.org/pgsql-bugs/2000-12/msg00093.php

). This is currently causing a problem for me, and I might (no
promises) be interested in implementing it. So I'm testing the waters.
If I did submit a patch for this, would the developers here be
interested?

j


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Re: implementing query timeout

From
Bruce Momjian
Date:
Jessica Perry Hekman wrote:
> As has been noted on this list before, query timeouts are not implemented
> in pgsql-jdbc (see
>
>   http://archives.postgresql.org/pgsql-bugs/2000-12/msg00093.php
>
> ). This is currently causing a problem for me, and I might (no
> promises) be interested in implementing it. So I'm testing the waters. If
> I did submit a patch for this, would the developers here be interested?

Let me also add that Cancel now works in the CVS copy of the jdbc
driver.

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026

Re: implementing query timeout

From
Bruce Momjian
Date:
Jessica Perry Hekman wrote:
> As has been noted on this list before, query timeouts are not implemented
> in pgsql-jdbc (see
>
>   http://archives.postgresql.org/pgsql-bugs/2000-12/msg00093.php
>
> ). This is currently causing a problem for me, and I might (no
> promises) be interested in implementing it. So I'm testing the waters. If
> I did submit a patch for this, would the developers here be interested?

[ Hackers list added.]

You bet, but it would be done in the backend, not in jdbc.  Is that OK?

I have some ideas that should make it pretty easy.  If you set an
alarm() in the backend on transaction start, then call the query
cancel() code if the alarm() goes off, that should do it.  Of course,
you reset the alarm if the query finishes before the timeout.


--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026

Re: implementing query timeout

From
Jessica Perry Hekman
Date:
On Wed, 13 Mar 2002, Bruce Momjian wrote:

> You bet, but it would be done in the backend, not in jdbc.  Is that OK?

Theoretically this is okay. I am more comfortable in Java than in C and I
hadn't looked at the backend code at all, but I'll take a peek and see if
it looks like something I'd feel comfortable doing.

> I have some ideas that should make it pretty easy.  If you set an
> alarm() in the backend on transaction start, then call the query
> cancel() code if the alarm() goes off, that should do it.  Of course,
> you reset the alarm if the query finishes before the timeout.

Sounds straightforward enough. Hopefully I'll get a chance to look at this
before the end of this week.

Thanks!

Jessica



problems with Tomcat and postgres

From
"Jose Javier Gutierrez"
Date:
Hi friends,
    I have problems with postgres.jar and tomcat. I have de follow exception :

- Excepcion de persistencia:
com.kristinaIbs.persistence.ExceptionPersistence: ManagerPersistencePool
(getConnection).Connection refused. Check that the hostname and port is
correct, and that the postmaster is running with the -i flag, which enables
TCP/IP networking.
        at
com.kristinaIbs.persistence.ManagerPersistencePool.getConnection(ManagerPers
istencePool.java:112)
        at
com.kristinaIbs.user.UserManager.getUserByLogin(UserManager.java:314)

I have the follows parameters :
     driver      = org.postgresql.Driver
    url      = jdbc:postgresql://192.168.0.7:5432/easysite
    user      = postgres
    password =

Do you can Help please!!!!!


-----Mensaje original-----
De: pgsql-jdbc-owner@postgresql.org
[mailto:pgsql-jdbc-owner@postgresql.org]En nombre de Bruce Momjian
Enviado el: miercoles 13 de marzo de 2002 21:23
Para: Jessica Perry Hekman
CC: pgsql-jdbc@postgresql.org; PostgreSQL-development
Asunto: Re: [JDBC] implementing query timeout


Jessica Perry Hekman wrote:
> As has been noted on this list before, query timeouts are not implemented
> in pgsql-jdbc (see
>
>   http://archives.postgresql.org/pgsql-bugs/2000-12/msg00093.php
>
> ). This is currently causing a problem for me, and I might (no
> promises) be interested in implementing it. So I'm testing the waters. If
> I did submit a patch for this, would the developers here be interested?

Let me also add that Cancel now works in the CVS copy of the jdbc
driver.

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026

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Re: problems with Tomcat and postgres

From
Auri Mason
Date:
Hi friend ;P

The first problem that I can see is a clear "Connection refused".
Befor investigate if the cause is Tomcat or something else, correct this
error! Be sure that the postmaster is running with the -i

p.s. usually my run.sh is like:
"./postmaster -i -D /home/me/postgresql/data > logfile 2>&1 &"

Ciao, Auri

On Thu, 14 Mar 2002, Jose Javier Gutierrez wrote:

> Hi friends,
>     I have problems with postgres.jar and tomcat. I have de follow exception :
>
> - Excepcion de persistencia:
> com.kristinaIbs.persistence.ExceptionPersistence: ManagerPersistencePool
> (getConnection).Connection refused. Check that the hostname and port is
> correct, and that the postmaster is running with the -i flag, which enables
> TCP/IP networking.
>         at
> com.kristinaIbs.persistence.ManagerPersistencePool.getConnection(ManagerPers
> istencePool.java:112)
>         at
> com.kristinaIbs.user.UserManager.getUserByLogin(UserManager.java:314)
>
> I have the follows parameters :
>      driver      = org.postgresql.Driver
>     url      = jdbc:postgresql://192.168.0.7:5432/easysite
>     user      = postgres
>     password =
>
> Do you can Help please!!!!!


Re: [HACKERS] problems with Tomcat and postgres

From
Doug McNaught
Date:
"Jose Javier Gutierrez" <jgutierrez@kristina.es> writes:

> com.kristinaIbs.persistence.ExceptionPersistence: ManagerPersistencePool
> (getConnection).Connection refused. Check that the hostname and port is
> correct, and that the postmaster is running with the -i flag, which enables
> TCP/IP networking.

Is the postmaster indeed listening on a TCP/IP port, (usually 5432) or
just on the Unix-domain socket?  You have to specifically turn on
TCP/IP for security reasons--it's not enabled by default.

-Doug
--
Doug McNaught       Wireboard Industries      http://www.wireboard.com/

      Custom software development, systems and network consulting.
      Java PostgreSQL Enhydra Python Zope Perl Apache Linux BSD...

Re: implementing query timeout

From
Bruce Momjian
Date:
Jessica Perry Hekman wrote:
> I am still unable to post to the hackers list. I sent a second attempt, a
> few days after subscribing; I sent mail to pgsql-hackers-owner (no
> response, though maybe that didn't go through either); I subscribed from a
> second account, waited a few hours, and send mail (twice) from there
> (again, no bounce and it didn't go through). I am at a loss. Is there some
> special way to subscribe? (I filled my address into the form at
> http://webmail.postgresql.org/cgi-bin/mj_wwwusr?domain=postgresql.org&func=lists-long-full&extra=pgsql-hackers,
> but maybe that just lets me read and not post?).
>
> I'm sorry to keep asking for your help on this, but I am frustrated and
> not sure what else to do at this point.

Jessica, you had asked about implementing a jdbc timeout a while back,
and we got stuck on implementing it in the backend with an alarm()
timeout and a Cancel, and the fact that SET in a transaction would not
roll back.

Well, we have committed fixes to the current CVS to roll back a SET in a
transaction:

    test=> SHOW australian_timezones;
    INFO:  australian_timezones is off
    test=> BEGIN;
    BEGIN
    test=> SET australian_timezones TO true;
    SET
    test=> SHOW australian_timezones;
    INFO:  australian_timezones is on
    test=> ABORT;
    ROLLBACK
    test=> SHOW australian_timezones;
    INFO:  australian_timezones is off

This means we can now create a SET variable that does an alarm/cancel
timeout in a transaction, and know that it can safely bracket a
statement because it will reset if the transaction aborts.

Are you still interested in working on this?

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026

Re: implementing query timeout

From
Bruce Momjian
Date:
Jessica P. Hekman wrote:
> On Fri, 7 Jun 2002, Bruce Momjian wrote:
>
> > This means we can now create a SET variable that does an alarm/cancel
> > timeout in a transaction, and know that it can safely bracket a
> > statement because it will reset if the transaction aborts.
> >
> > Are you still interested in working on this?
>
> Very possibly. Could I get just a little hand-holding about how to create
> a new SET variable -- along the lines of "another place where a SET
> variable is defined is in this method, so just imitate what is done
> there"?

Sure, you can chat with me via:

    AIM     bmomjian
    ICQ     151255111
    Yahoo   bmomjian
    MSN     root@candle.pha.pa.us
    IRC    #postgresql vis efnet

or via email.  I can do the SET stuff for you if you wish.

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026

Re: implementing query timeout

From
"Jessica P. Hekman"
Date:
On Fri, 7 Jun 2002, Bruce Momjian wrote:

> This means we can now create a SET variable that does an alarm/cancel
> timeout in a transaction, and know that it can safely bracket a
> statement because it will reset if the transaction aborts.
>
> Are you still interested in working on this?

Very possibly. Could I get just a little hand-holding about how to create
a new SET variable -- along the lines of "another place where a SET
variable is defined is in this method, so just imitate what is done
there"?

j