Well, nothing to lose, so I did a touch on pg_clog/0CDE and at least
the error changed. Now it says:
DETAIL: Could not read from file "pg_clog/0CDE" at offset 98304:
Success.
But I don't understand why it says Success?
On 7/17/2014 4:09 PM, Scott Whitney
wrote:
OOhhh...IIRC I think that I created the clog file as a zero
byte file to get around that. It was _absolutely_ a step of
last resort. I would be certain that you have a backup that
can get you back to this point at least before proceeding.
I was attempting to do that with one table that I know is
broken, but I can't get anything from it in a select. All I
get no matter what is:
ERROR: could not access status of transaction 3706060803
DETAIL: Could not open file "pg_clog/OCDE": No such file or
directory
I think the pg_clog files are transaction journal files that
tell the Db why a record is or is not in the table, but I'm
not certain. I just wish there was a pg_resetclog executable
like there is for the pg_xlog segments.
On 7/17/2014 3:58 PM, Scott
Whitney wrote:
Yeah. I know the feeling, man. What I ended up doing
was "select * from" until I found the broken one then
jumped down into groups of thousands of records and
basically "Newtoned" it down until I found the affected
data.
It sucked. A lot.
Well, we already have the schema in a canned file. So,
we wouldn't need to do a pg_dump for the schema, and I
can get into the database using psql obviously. That's
how I produced the setting from pg_settings. But, I
really don't want to have to go through 150K+ records to
find the multiple broken ones, if I don't have to do so.
I'm just hoping for a faster way.
On 7/17/2014 3:30 PM, Scott
Whitney wrote:
Well, at this point, let me let the big brains
answer your main question on the thread and tell
you what _I_ did when I got into a similar
situation.
a) pg_dump --schema-only <database name>
> db.structure
b) From here it was a lot of select * from
table until I found the broken one(s) and I worked
around the actual bad data by offset/limit on the
selects on the busted tables.
It took me several hours, but it did work (for
me).
That's assuming you can even psql to the db in
the first place when the postmaster is running.
We're only working with a single database on this
system, and yes, I attempted a pg_dump earlier
today on just one single table - it failed (I know
pg_dump and pg_basebackup use different
mechanisms.) Mind you it's a large table with
154,000 rows in it. The overall database is
somewhere around 43GB.
On 7/17/2014 3:16 PM,
Scott Whitney wrote:
a) How many databases do you have?
b) Have you tried to pg_dump the
database(s) to see if that succeeds?
If you _can_ pg_dump (which you might
or might not be able to do), you could
re-init the cluster and restore.
Hi
all,
You may have seen my post from yesterday
about our production database getting
corrupted. Well, this morning we brought the
system down to single user and ran an fsck
which did
report some drive errors. We repeated until
no additional errors were reported. Then, we
brought the system back to multi-user status
and ran a successful pg_basebackup on the
broken database. Since then we restarted the
database and a ps -ef result looks like:
/usr/pgsql-9.2/bin/postmaster -D
/opt/datacenter -o -c
zero_damaged_pages=true -i -N 384 -p 5431
After the Db started up, we ran a VACUUM
FULL ANALYZE which ran for about 3 hours,
but the database is still showing the same
type of errors in its log: invalid page
header in
block 29718... etc. What disturbed me a
little, is that I don't think the
zero_damaged_pages got applied. Checking the
pg_settings table, we got:
select name, setting, boot_val, reset_val
from pg_settings where name =
'zero_damaged_pages';
name |
setting | boot_val | reset_val
---------------------------------------------------------------------------------
zero_damaged_pages | on | off
| on
Now, my colleague ran this after he tried
running some operations again after I told
him how to set zero_damaged_pages again. He
swears that that it was on when the first
VACUUM
FULL ANALYZE was run, but I'm not as sure.
Plus, I don't understand why the boot_val
shows as off. In any event, as we're still
getting log errors like before, I don't
really know
what to try next other than rerunning the
VACUUM FULL again. Help?
--
Jay
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