Subject: Postgres v4.2? OSF/1 Port?

From: Brian Holman <[email-masked]>
Date: Fri, 28 Jan 1994 15:36:15 +119303928 (MST)

Quoted from Mike Stonebraker <[email-masked]>

>We both agreed that code freeze will be 2/1.  She will either have her "new"
>implementation robust and as functional as the old one by that date, or she
>will fall back to the "old" implementation.

>As such, we can move ahead with a schedule based on a firm 2/1 code freeze.

Does this mean that the Postgres V4.2 is near completion?  Is there a
estimated release date yet?  Is the DEC Alpha OSF/1 port sufficently stable
to be included in the next release?

Another question:  I'm running Postgres V4.1 on a DECStation 5000 running
Ultrix.  I have some non-critical production databases running on it that
log statistical information.  In other words, there are alot of very brief
transactions being send to the postmaster.

About once a day the postmaster dies and has to be restarted.  I wrote the
following script to eliminate the need for a human to restart the
postmaster.  It gets run as "pgloop.csh &".

-------pgloop.csh--------
#!/bin/csh
while 1 == 1
	postmaster
	mail -s "Backend went down" bkh@liblas </dev/null
	sleep 30
end
-------------------------

Why is the back end keep going down?  Is it the number of "postgres"
processes running at a time?  Does shared memory just get screwed up every
once in a while or what?  Any ideas would be appreciated.

-- 
+--------------------------+-------------------------------------+
| BRIAN K. HOLMAN          | E-Mail:        [email-masked] |
| Programmer/Analyst       | Mail:    2330 HBLL, Provo, UT 84602 |
| Library Automations      | Phone:               (801) 378-8162 |
| Brigham Young University | Fax:                 (801) 378-3221 |
+--------------------------+-------------------------------------+

---

From: [email-masked] (Paul M. Aoki)
Date: Fri, 28 Jan 1994 16:16:53 -0800

> Quoted from Mike Stonebraker <[email-masked]>
[...]

whoops, that wasn't supposed to go out on this mailing list.
i botched my mailing list mux/demux :-(  sorry 'bout that.

> Does this mean that the Postgres V4.2 is near completion?

yes.  can't imagine release will be more than a couple of weeks
after code freeze.

> Is the DEC Alpha OSF/1 port sufficently stable to be included in 
> the next release?

i think so.  it's what i'm using these days for my development work,
anyway.

> once in a while or what?  Any ideas would be appreciated.

when a backend dies unexpectedly, the postmaster detaches its 
shared resources and reinitializes from scratch.  (i don't think 
there's any good reason to actually detach the resources before 
reinitializing, but there it is.)  sometimes it fails to reattach 
(it prints out a message when this happens) and terminates.

i think this was partly due to the way backends neglected to shmdt 
(detach) when going down.  this would occasionally cause the postmaster 
to "leak" shared resources (which couldn't be deallocated by the OS 
because it thought a process was still attached).  i changed the 
shared memory stuff to shmdt and i didn't see this problem anymore on
ultrix 4.2a.  we upgraded the sequoia 2000 db server machine to ultrix 
4.3a and the problem seemed to go away in the old code, too -- it was
up for about two months without this problem.

i think i sent that shmdt change to robert withrow, who was reporting 
something similar under SVR4, to see if that solved his problem.  i 
don't remember what his conclusion was, though.
--
  Paul M. Aoki  |  CS Div., Dept. of EECS, UCB  |  [email-masked]
                |  Berkeley, CA 94720           |  ...!uunet!ucbvax!aoki

---

From: Brian Holman <[email-masked]>
Date: Thu, 3 Feb 1994 11:34:29 +119303928 (MST)

> don't remember what his conclusion was, though.

Is the "old code" the release of 4.1 available on the ftp site?  Is the "new
code" available?  I noticed a sequoia 2000 tar file on s2k-ftp.  Does this
contain the fix and is it rightful for me to get it not having anything to
do with sequoia?
-- 
+--------------------------+-------------------------------------+
| BRIAN K. HOLMAN          | E-Mail:        [email-masked] |
| Programmer/Analyst       | Mail:    2330 HBLL, Provo, UT 84602 |
| Library Automations      | Phone:               (801) 378-8162 |
| Brigham Young University | Fax:                 (801) 378-3221 |
+--------------------------+-------------------------------------+

---

From: [email-masked] (Paul M. Aoki)
Date: Thu, 03 Feb 1994 11:09:32 -0800

Brian Holman <[email-masked]> writes:
> Is the "old code" the release of 4.1 available on the ftp site?

yup.

> Is the "new code" available?

not currently.  unless it's really urgent, i'd just wait until
4.2 is out.  (we actually froze on tuesday and are currently in
the process of generating release notes and such..)

> I noticed a sequoia 2000 tar file on s2k-ftp.  Does this
> contain the fix 

nope.

> and is it rightful for me to get it not having anything to
> do with sequoia?

you can, if you like, but it's not "database compatible" so it forces 
another round of copy in/copy out -- i wouldn't advise it.
--
  Paul M. Aoki  |  CS Div., Dept. of EECS, UCB  |  [email-masked]
                |  Berkeley, CA 94720           |  ...!uunet!ucbvax!aoki