Re: [GENERAL] Recovery Assistance

On 01/27/2017 01:31 PM, Brian Mills wrote:

Hi,

I have a Atlassian Confluence Wiki that depends on postgres, but I
haven't much experience with postgres other than for this purpose.

A few days ago, the hard disk filled, so all services stopped working.
When the admin realised this he increased the disk size (its in a cloud,
so that was easy to do) however I think the way it shutdown left
Postgres in an inconsistent state for some reason.
Now when I start it up I get this message in the log over and over again:
"FATAL:  the database system is starting up"

I have a backup, which I have successfully recovered, but it is 24 hours
old, the next backup was the cause of the disk filling. So I'm using
this as exercise in learning a bit more about postgres.

I did some research and found a number of options. I took a file level
backup with the service not running then tried 2 things. I haven't found
much else on what to do though.

*Attempt 1 - Reset Log *

It sounded like this shouldn't be my first option (it wasn't) but it did
sound like what I needed to do.
I ran this command
./pg_resetxlog /var/lib/postgresql/9.3/main -f
It worked a treat, the database did startup ok.
However when I tried to dump the DB:
root@atlassian:/home/myuser# sudo -u postgres pg_dump confluencedb >
$now-confluencedb.sql
pg_dump: Dumping the contents of table "bodycontent" failed:
PQgetResult() failed.
pg_dump: Error message from server: ERROR:  unexpected chunk size 104
(expected 1996) in chunk 3 of 22 for toast value 48862 in pg_toast_20028
pg_dump: The command was: COPY public.bodycontent (bodycontentid, body,
contentid, bodytypeid) TO stdout;
The dump failed, so I assume this did leave my database in an
inconsistent state.


*Attempt 2 -  startup manually and let it try recovery*

I restored my file level backup and started again.
This time I tried to startup manually on the command line to see the
output (I'd done it as a service startup a number of times to nearly the
same effect too)

postgres@atlassian:/usr/lib/postgresql/9.3/bin$ ./pg_ctl -D
/etc/postgresql/9.3/main start
server starting
postgres@atlassian:/usr/lib/postgresql/9.3/bin$ 2017-01-27 20:36:08 AEDT
LOG:  database system was interrupted while in recovery at 2017-01-27
20:13:26 AEDT
2017-01-27 20:36:08 AEDT HINT:  This probably means that some data is
corrupted and you will have to use the last backup for recovery.
2017-01-27 20:36:08 AEDT LOG:  database system was not properly shut
down; automatic recovery in progress
2017-01-27 20:36:08 AEDT LOG:  redo starts at 5/528B4558
2017-01-27 20:36:18 AEDT LOG:  redo done at 5/A3FFF9E8
2017-01-27 20:36:18 AEDT LOG:  last completed transaction was at log
time 2017-01-24 02:08:00.023064+11
2017-01-27 23:00:01 AEDT FATAL:  the database system is starting up
2017-01-27 23:00:01 AEDT FATAL:  the database system is starting up

What does ps ax | grep post show?

Is the cluster set up to log to a file, if so what does it show?

Does the system log show anything relevant?

I've left it that way for 12 hours, and its still not allowing connections.
I assume its doing some kind of consistency check?

What does it say when you attempt a connection?

Does anyone have any suggestions on what I should be doing to try and
restore this database?

- The amount of change is minimal in the DB after 6pm it should be
basically no change overnight.
- The log above seems to suggest it has completed a redo ok, is that right?
- The last completed transaction time 2017-01-24 02:08:00.023064+11 the
log mentions would be fine to use, so loosing even a few hours before
that would be more than adequate.

I'm just not clear what the database is doing now, or how I should be
trying to recover it.

Any help anyone can suggest would be great! I've given myself this
weekend to attempt to recover more than the last backup, after that I
need to restore the service for my team to use and suck up the lost last
day of updates.

Thanks,
Brian

--
Adrian Klaver
adrian.klaver@aklaver.com