Re: Mysterious DB reset - Mailing list pgsql-general

On 03/07/2014 11:08 AM, Israel Brewster wrote:
> On Mar 6, 2014, at 1:25 PM, Steve Crawford <scrawford@pinpointresearch.com> wrote:
>
>> On 03/06/2014 09:33 AM, Israel Brewster wrote:
>>> For starters, this happened again this morning (no data prior to 4:45 am and sequence reset), so whatever is going
onappears to be reoccurring. Also, I forgot to mention if it is significant: this is running on slackware liunux 14.0 
>>>
>>>
>>> Also odd is that my cleanup script runs at 1am. I have records of there
>>> being new data in the database up to 3:51am, but the oldest record
>>> currently in the DB is from 4:45am (as specified by the default of now()
>>> on the column). So I know records were added after my delete command
>>> ran, but before this reset occurred.
>>>
>> A shot in the dark...
>>
>> Have you searched /etc/crontab, root's crontab, PostgreSQL's crontab and the crontabs of any automatic scripts that
connect.I'm not sure about Slackware but Red Hat and Centos run the cron.daily scripts at (wait for it...) just after
4am.
>
> Good shot - you nailed it! I found a rouge script in /etc/crontab.daily that ran the following line at 4:40am:
>
> /usr/local/pgsql/bin/pg_dump -h <domain name of localhost> -U tracking -cs | /usr/local/pgsql/bin/psql -U postgres
tracking
>
> It must have been left over from before I got streaming replication up and working, when this box was still the
backupserver and not primary -i.e. the domain name in the first half wasn't for the local machine until I swapped
machines.Apparently when you do a pg_dump with the -c flag from a server to itself, it does the clean before reading
thedata, resulting in a new empty database. Thanks again for all the suggestions! 

No, -c just tells pg_dump to output clean commands and really only has
meaning when you do a plain text dump as above. pg_dump does not clean
the data from the running server on its own. What did the cleaning was
immediately piping to output of the dump to psql. So basically you
created a plain text dump file and fed it back to the server and the
dump file included commands to clean out objects. If you had not used -c
you would have gotten a bunch of duplicate <something> errors.


>
>>
>> Some of the default daily scripts like logrotate can have "side effects" like restarting the service that writes to
thelog file being rotated. 
>>
>> Cheers,
>> Steve
>>
>>
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>
>


--
Adrian Klaver
adrian.klaver@aklaver.com