Re: max_wal_senders must die

"Joshua D. Drake" wrote:
> On Wed, 2010-10-27 at 19:52 -0400, Robert Haas wrote:
>> Josh Berkus wrote:
>
>>> *you don't know* how many .org users plan to implement
>>> replication, whether it's a minority or majority.
>>
>> None of us know. What I do know is that I don't want PostgreSQL to
>> be slower out of the box.
>
> Poll TIME!

If you do take a poll, be careful to put in an option or two to deal
with environments where there is "surgical" implementation of
replication features. We'll almost certainly be using SR with a
custom WAL receiver as part of our solution for our biggest and most
distributed data set (circuit court data), but an "out of the box"
drop in usage there is not in the cards anytime soon; whereas we're
already using HS/SR "out of the box" for a small RoR web app's data.

By the way, the other three DBAs here implemented the HS/SR while I
was out for a couple days while my dad was in the hospital (so they
didn't want to even bother me with a phone call). They went straight
from the docs, without the benefit of having tracked any PostgreSQL
lists. They told me that it was working great once they figured it
out, but it was confusing; it took them a lot of time and a few false
starts to get it working. I've been trying to get details to support
an improvement in documentation, but if those guys had problems I
agree we need to do *something* to make this simpler -- they're
bright professionals who manage hundreds of PostgreSQL databases on a
full time basis.

-Kevin

On Thu, 2010-10-28 at 07:05 -0500, Kevin Grittner wrote:
> "Joshua D. Drake" wrote:
> > On Wed, 2010-10-27 at 19:52 -0400, Robert Haas wrote:
> >> Josh Berkus wrote:
> >
> >>> *you don't know* how many .org users plan to implement
> >>> replication, whether it's a minority or majority.
> >>
> >> None of us know. What I do know is that I don't want PostgreSQL to
> >> be slower out of the box.
> >
> > Poll TIME!
>
> If you do take a poll, be careful to put in an option or two to deal
> with environments where there is "surgical" implementation of
> replication features.

And Poll it is:

https://www.postgresqlconference.org/content/replication-poll

You don't have to login to take it but of course it helps with validity
of results.

Sincerely,

Joshua D. Drake

--
PostgreSQL.org Major Contributor
Command Prompt, Inc: http://www.commandprompt.com/ - 509.416.6579
Consulting, Training, Support, Custom Development, Engineering
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> https://www.postgresqlconference.org/content/replication-poll
>
> You don't have to login to take it but of course it helps with validity
> of results.

Oh, I'd already put something up on http://www.postgresql.org/community

--
-- Josh Berkus
PostgreSQL Experts Inc.
http://www.pgexperts.com

On Thu, 2010-10-28 at 16:25 -0700, Josh Berkus wrote:
> > https://www.postgresqlconference.org/content/replication-poll
> >
> > You don't have to login to take it but of course it helps with validity
> > of results.
>
> Oh, I'd already put something up on http://www.postgresql.org/community

Sorry, didn't know... I have 122 responses so far, which I think will be
surprising (some of them certainly surprised me). I will keep it open
until next week and then post the results.

JD

--
PostgreSQL.org Major Contributor
Command Prompt, Inc: http://www.commandprompt.com/ - 509.416.6579
Consulting, Training, Support, Custom Development, Engineering
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> Sorry, didn't know... I have 122 responses so far, which I think will be
> surprising (some of them certainly surprised me). I will keep it open
> until next week and then post the results.

Well, for any community site poll, I hope you realize that there's a LOT
of sampling error. Here's another one:

http://www.postgresql.org/community/survey.71

--
-- Josh Berkus
PostgreSQL Experts Inc.
http://www.pgexperts.com

On Thu, 2010-10-28 at 17:12 -0700, Josh Berkus wrote:
> > Sorry, didn't know... I have 122 responses so far, which I think will be
> > surprising (some of them certainly surprised me). I will keep it open
> > until next week and then post the results.
>
> Well, for any community site poll, I hope you realize that there's a LOT
> of sampling error. Here's another one:
>
> http://www.postgresql.org/community/survey.71
>

Oh sure. I don't expect this to be some kind of authoritative reference
but it is certainly worth at least reviewing. If nothing else it is fun
to see the responses and consider their meaning based on your own views.

JD

--
PostgreSQL.org Major Contributor
Command Prompt, Inc: http://www.commandprompt.com/ - 509.416.6579
Consulting, Training, Support, Custom Development, Engineering
http://twitter.com/cmdpromptinc | http://identi.ca/commandprompt

[going back on list with this]

Selena Deckelmann <selenamarie(at)gmail(dot)com> wrote:
> Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov wrote:

>> the other three DBAs here implemented the HS/SR while I was out

>> They told me that it was working great once they figured it out,
>> but it was confusing; it took them a lot of time and a few false
>> starts to get it working. I've been trying to get details to
>> support an improvement in documentation

> Just curious -- did they use the wiki documentation at all? Was
> any of that more or less helpful?

I finally got a chance to chat with the other DBAs about this --
they actually *just* looked at the Wiki to get through it, and
didn't go to the manual at all. They eventually concluded that the
problems were all because this was done on a machine where we had
multiple major releases of PostgreSQL running for different database
clusters, and the version on $PATH was not changed to 9.0. Even
though they started PostgreSQL on the standby server with an
explicit path to the 9.0 version, it seemed to find some executable
or library from 8.4 on $PATH, resulting in bizarre and unhelpful
error messages.

We do our own builds with a prefix like /usr/local/pgsql-9.0.1 and
create a symlink from /usr/local/pgsql to what we want as the
default on the machine, when an explicit path is not specified.
When they pointed the symlink to 9.0.1 everything worked as
expected.

They said that except for the quirky path behavior, the installation
went fine; the Wiki page instructions were clear and adequate and
that installation process was not difficult or confusing.

This path issue sounds like a bug to me....

-Kevin

Hi,

On Wednesday 03 November 2010 20:28:03 Kevin Grittner wrote:
> They said that except for the quirky path behavior, the installation
> went fine; the Wiki page instructions were clear and adequate and
> that installation process was not difficult or confusing.
>
> This path issue sounds like a bug to me....
I guess you built both in the same place and just prefix installed it to
different directories?
That can cause issues like that unless you use --disable-rpath.

Andres

Andres Freund <andres(at)anarazel(dot)de> wrote:

> I guess you built both in the same place and just prefix installed
> it to different directories?

We always build in a directory tree with a name based on the
version, with a prefix based on the version. This is routine for
us. I have a hard time believing that they made an error on that,
but I'll try to re-create in a controlled way so that I can report
specific error messages and confirm my assumptions.

-Kevin