Обсуждение: How to recover Data

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How to recover Data

От
p_appu@yahoo.com (Padmanab Sridhar)
Дата:
I had a m/c with Postgres 7.2 and huge amount of data. on Power
failure and restart of the m/c pgsql refused connect to any of the
database. Being an invoice i took a tar of the data dir.
I tried reinstalling PGSQL and copied the data dir to the same dir
where the new data is being stored. ie
cp /backup/pgsql/data /var/lib/pgsql/data

When i connect to the old database i am able to connect but when i do
a \d to list the tables i get no relations found. Also when i do
select * from a table i am able to get the structure but it has no
records in it.
WHen i check the same info in pg_database to check if the old database
entry is present i dont find it.
Can someone help me as to how to recover my data???
Basically what i feel is update the pg_tables.
Thanks and rgds
Padmanab


Re: How to recover Data

От
Дата:
Sridhar

such questions shud be posted to pgsql-admin list.

generally in case of power failure pgsql is unable to remove its
pid file., if u are using RPM based installation the file shud be in
/var/lib/pgsql/ in the name of postmaster.pid

If such a file exists postmaster will refuse to start. in such case
first remove that file. then start postmaster using


# /etc/rc.d/init.d/postgresql start

or better

# su - postgres
$ pg_ctl -l logfile -D /var/lib/pgsql/data

observe the recovery messages in logfile using
$tail -f logfile

in general such recoveries mostly succeeds and in no case
shud be inturrupted to avoid further (grave) complications.

Good Luck with your data,

regds
mallah.

PS: its not easy to loose data with pgsql ;-)


> I had a m/c with Postgres 7.2 and huge amount of data. on Power
> failure and restart of the m/c pgsql refused connect to any of the database. Being an invoice i
> took a tar of the data dir.
> I tried reinstalling PGSQL and copied the data dir to the same dir where the new data is being
> stored. ie
> cp /backup/pgsql/data /var/lib/pgsql/data



Only data directory is not sufficeint u need the pg_xlog directory as
well.

In any case such backups in prociple are not ok unless postmaster
is shut down during the cp.


>
> When i connect to the old database i am able to connect but when i do a \d to list the tables i
> get no relations found. Also when i do
> select * from a table i am able to get the structure but it has no records in it.
> WHen i check the same info in pg_database to check if the old database entry is present i dont
> find it.
> Can someone help me as to how to recover my data???
> Basically what i feel is update the pg_tables.
> Thanks and rgds
> Padmanab
>
> ---------------------------(end of broadcast)--------------------------- TIP 6: Have you
> searched our list archives?
>
> http://archives.postgresql.org



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