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Data Bases > Pgsql General > Re: Losing data
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Re: Losing data

by aklaver@[EMAIL PROTECTED] (Adrian Klaver) Jun 19, 2008 at 05:52 PM

-------------- Original message ----------------------
From: Garry Saddington <garry@[EMAIL PROTECTED]
>
> On Thursday 19 June 2008 16:55, Joshua D. Drake wrote:
> > On Thu, 2008-06-19 at 16:55 +0100, Garry Saddington wrote:
> > > I have had a serious loss of data and wondered if anyone could shed
any
> > > light on what may have happened.
> > > My users have been writing re****ts on students. No error messages
have
> > > been produced and when called back up the re****ts seem to be present
at
> > > the time of writing. However, next day they have disappeared, and
they do
> > > not appear in a pg_dump. They seem to have been kept in memory and
never
> > > written to disk.
> > > We are using Zope and connecting to Postgres through psycopg on
Centos 5.
> > > I suspect a hard disk failure but any other ideas would be welcome.
> > > Would these re****ts be in the WAL?
> >
> > If it was hardware related you would know, quickly. This sounds a
great
> > deal more like an application level interaction. Perhaps your zope
> > application caches things for a while before committing to disk?
> Yes I thought of this but once the re****t is sent to the DB a separate
query 
> is run to get all of that teacher's re****ts and these are then displayed
on a 
> new page. They all appear here but then disappear later. Zope has
transaction 
> machinery that rolls everything back on an error, so Postgres must have 
> indicated a successful write somehow.  I read in a Postgres manual that
the 
> hard disk may re****t to the OS that a write has occured when it actually
has 
> not, is this possible? Oh, and the problem has been intermittant.
Another 
> thing that happened this morning is that Postgres had today as
18/06/2008 
> when in fact it was 19/06/2008 and the OS re****ted this correctly.
Restarting 
> postgres sorted it, could this be the problem?
> Regards
> Garry
> 

Seems like a transaction with no commit. Basically along as the session is
active the data is there but once the session is closed the data does not
persist.

--
Adrian Klaver
aklaver@[EMAIL PROTECTED]
 

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 4 Posts in Topic:
Re: Losing data
aklaver@[EMAIL PROTECTED]  2008-06-19 17:52:06 
Re: Losing data
garry@[EMAIL PROTECTED]   2008-06-19 19:12:01 
Re: Losing data
jd@[EMAIL PROTECTED] (&q  2008-06-19 11:11:43 
Re: Losing data
pgsql@[EMAIL PROTECTED]   2008-06-20 03:58:29 

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tan12V112 Sat Nov 22 16:19:07 CST 2008.