Re: Detecting corrupt table

you might want to log any errors resulting from pg_dump and then grep
through them to verify. or you could record the exit status ( $? ) for each
pg_dump command.

I was also thinking about how to check if something malformed your data on
disk. I could think of some ways to do that, but it doesn't look like you
are looking for that.

hth

WBL

On Wed, Apr 18, 2012 at 12:05 AM, David Larochelle <
dlarochelle(at)cyber(dot)law(dot)harvard(dot)edu> wrote:

> Our database has some corrupt tables and I'm trying to figure out what
> data can be salvaged and what needs to be restored from backup or
> regenerated.
>
> Initially I tried running select count(*) on all user tables. While this
> did detect some corrupt tables, it missed others. For example, I was able
> to run count(*) on a table but then got an error while trying to back it up.
>
>
> pg_dump: Error message from server: ERROR: missing chunk number 0 for
> toast value 368243665 in pg_toast_284730161
> pg_dump: The command was: COPY public.stories (stories_id, media_id, url,
> guid, title, description, publish_date, collect_date, story_texts_id,
> full_text_rss) TO stdout;
>
>
>
> Is there a simple way to determine which parts of the database are
> corrupt? I'm currently running a script to back up each table individually
> using something like the following:
>
> psql -c "select tablename from pg_tables where tableowner = 'db_user'
> ORDER by tablename " | tail -n +3 | head -n -2 | xargs -n 1 -i pg_dump
> --verbose --table={} --file={}_.dump
>
>
> But I'm worried that this approach will also miss database corruption and
> was wondering if anyone has other suggestions.
>
> Thanks,
>
>
> David
>
>
>

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