IDS Forum

Re: Temp log files in rootdbs during warm restore

Posted By: Andreas Legner
Date: Monday, 5 December 2016, at 5:09 a.m.

In Response To: Temp log files in rootdbs during warm restore (JACOB SALOMON)

Hi Jacob,

just quickly: those temp log files are created as temp partitions and=20
hence follow "general" temp table allocation rules ... and would be=20
subject to same temp table allocation rule flaws.

I'd say one more reason to catch up with time and bring this to a current=20
version ;-)

Cheers,
Andreas

From: "JACOB SALOMON" <jakesalomon@yahoo.com>
To: ids@iiug.org
Date: 05.12.2016 06:28
Subject: Temp log files in rootdbs during warm restore [38227]
Sent by: ids-bounces@iiug.org

Greetings, Family.=20

I recently had a misadventure and would like to gain further insight into=20
the=20
issues of concern. My client is on IDS 11.5 (despite 3 years of bugs and=20
nagging to upgrade already! But that's another story.)=20

My client DBA inadvertently blew away a chunk, realizing his mistake an=20
ohno!second later. We therefore had to perform a warm restore of the=20
chunk,=20
followed by the log restore. (We chose to do it in 2 steps.)=20

During the log restore, the rootdbspace filled up and the rollforward=20
operation barfed. When we restarted the process I ran onstat -l to view=20
info=20
on the temp logs. Aha! Every blessed one was in rootdbs, rather than in=20
the=20
expected temp DBspaces specified by the DBSPACETEMP parameter. We had even =

exported a DBSPACETEMP environment variable with the same values. No help; =

it=20
just wanted to use the root. What did we do? We quickly added enough=20
chunks to=20
rootdbs to contain the temp logs at the same size of the actual logs,=20
about=20
18GB. So the chunk recovery completed and we're back in business.=20

Crisis over, I had the chance to think about the WHY; why was it ignoring=20
the=20
DBSPACETEMP and creating the temp logs in the root? I posed the following=20
theory to the Informix tech support on that PMR but he has not replied. So =

I=20
ask the community. Here is my theory:=20

1. The onparams command, which we use to add new logical logs, has a=20
default=20
DBspace for each new log: rootdbs. It?s only because onparams has -d=20
option=20
that we can place it in a DBspace of our choosing.=20

2. The onbar log-restore process creates as many ?temp logs? as the actual =

set. I believe it is creating them using an internal variation of=20
onparams. If=20
so, it is only reasonable - as per the default behavior of onparams - to=20
create them in rootdbs. And no DBSPACETEMP setting, be it in $ONCONFIG or=20
the=20
environment, is going to change that.=20

I also asked the tech if this behavior is more malleable in later=20
releases,=20
like creating the temp logs in DBSPACETEMP spaces, or if there is a=20
parameter=20
or env variable unbeknownst to me, that dictates where the recovery temp=20
logs=20
shall be created.=20

Can anyone out there fill in where my tech chickened out? This has=20
ramifications for any Informix server I configure in the future.=20

Thanks much!=20

-- Jacob Salomon=20
+--------------------------------------------------------------------------=
--+=20

| I didn't have time to write a short letter, so I wrote a long one=20
instead. |=20
+-------------------------------------------------------------- Mark Twain =

--+=20

***************************************************************************=
****=20

Forum Note: Use "Reply" to post a response in the discussion forum.=20

Messages In This Thread

• Temp log files in rootdbs during warm restore
  JACOB SALOMON -- Monday, 5 December 2016, at 12:27 a.m.
  • Re: Temp log files in rootdbs during warm restore
    Andreas Legner -- Monday, 5 December 2016, at 5:09 a.m.
  • RE: Temp log files in rootdbs during warm restore
    Everett Mills -- Monday, 5 December 2016, at 10:04 a.m.
    • Re: Temp log files in rootdbs during warm restore
      Art Kagel -- Monday, 5 December 2016, at 11:23 a.m.
    • Re: Temp log files in rootdbs during warm restore
      Art Kagel -- Monday, 5 December 2016, at 11:32 a.m.
      • Re: Temp log files in rootdbs during warm restore
        JACOB SALOMON -- Monday, 5 December 2016, at 1:00 p.m.
        • Re: Temp log files in rootdbs during warm restore
          JACQUES RENAUT -- Tuesday, 6 December 2016, at 10:51 a.m.

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