Обсуждение: How to get single table data from backup

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How to get single table data from backup

От
Andrus
Дата:

Hi!

Large database backup is created using

pg_dump -b -f backup.backup -F c 

How to restore single table in schema firma2 from it in Windows? 

Created database recovery and tried

pg_restore --schema-only --n firma2 -d recovery backup.backup
pg_restore -n firma2 -t tabletorecover -d recovery backup.backup

This fails since tabletorecover contains lot foreign key references. Foreign keys refer to other tables which have foreign keys to another tables etc. making huge graph. All tables contain also data.

I need to get table data only. Using PostgresSql 17 in windows.

Andrus.

Re: How to get single table data from backup

От
Adrian Klaver
Дата:
On 12/19/25 04:41, Andrus wrote:
> Hi!
> 
> Large database backup is created using
> 
> pg_dump -b -f backup.backup -F c
> 
> How to restore single table in schema firma2 from it in Windows?
> 
> Created database recovery and tried
> 
> pg_restore --schema-only --n firma2 -d recovery backup.backup
> pg_restore -n firma2 -t tabletorecover -d recovery backup.backup
> 
> This fails since tabletorecover contains lot foreign key references. 
> Foreign keys refer to other tables which have foreign keys to another 
> tables etc. making huge graph. All tables contain also data.
> 
> I need to get table data only. Using PostgresSql 17 in windows.

1) Does the table name tabletorecover occur in more then one SCHEMA?

2) Do you want only the table data for tabletorecover?

Assuming 1 is one SCHEMA only and 2 is tabletorecover data only then 
maybe something like:

1) pg_restore --schema-only --table=tabletorecover -d recovery backup.backup

2) In psql ALTER TABLE tabletorecover DROP CONSTRAINT the FK references 
in tabletorecover.

3) pg_restore --data-only --table=tabletorecover -d recovery backup.backup

> 
> Andrus.
> 
> 


-- 
Adrian Klaver
adrian.klaver@aklaver.com



Re: How to get single table data from backup

От
Ray O'Donnell
Дата:
On 19/12/2025 12:41, Andrus wrote:

> Hi!
>
> Large database backup is created using
>
> pg_dump -b -f backup.backup -F c
>
> How to restore single table in schema firma2 from it in Windows?
>
> Created database recovery and tried
>
> pg_restore --schema-only --n firma2 -d recovery backup.backup
> pg_restore -n firma2 -t tabletorecover -d recovery backup.backup
>
> This fails since tabletorecover contains lot foreign key references. 
> Foreign keys refer to other tables which have foreign keys to another 
> tables etc. making huge graph. All tables contain also data.
>
I haven't tried it, but - off the top of my head - how about:

(i) Create the table separately by hand, without the FK references.

(ii) Do a data-only restore, using the -a and -t options to pg_restore


Ray.




> I need to get table data only. Using PostgresSql 17 in windows.
>
> Andrus.
>
>
-- 
Ray O'Donnell // Galway // Ireland
ray@rodonnell.ie




Re: How to get single table data from backup

От
Adrian Klaver
Дата:
On 12/19/25 08:12, Adrian Klaver wrote:
> On 12/19/25 04:41, Andrus wrote:
>> Hi!
>>
>> Large database backup is created using
>>
>> pg_dump -b -f backup.backup -F c
>>
>> How to restore single table in schema firma2 from it in Windows?
>>
>> Created database recovery and tried
>>
>> pg_restore --schema-only --n firma2 -d recovery backup.backup
>> pg_restore -n firma2 -t tabletorecover -d recovery backup.backup
>>
>> This fails since tabletorecover contains lot foreign key references. 
>> Foreign keys refer to other tables which have foreign keys to another 
>> tables etc. making huge graph. All tables contain also data.
>>
>> I need to get table data only. Using PostgresSql 17 in windows.
> 
> 1) Does the table name tabletorecover occur in more then one SCHEMA?
> 
> 2) Do you want only the table data for tabletorecover?
> 
> Assuming 1 is one SCHEMA only and 2 is tabletorecover data only then 
> maybe something like:
> 
> 1) pg_restore --schema-only --table=tabletorecover -d recovery 
> backup.backup
> 
> 2) In psql ALTER TABLE tabletorecover DROP CONSTRAINT the FK references 
> in tabletorecover.
> 
> 3) pg_restore --data-only --table=tabletorecover -d recovery backup.backup
> 

An alternate method:

1) pg_restore  --table=tabletorecover --file recovery.sql
backup.backup
Here you are restoring the table structure and data to a text file.

2) Open the text file and remove the FK references from the table 
definition.

3) Then do psql -f recovery.sql -d recovery

If the amount of data is large and you don't want to deal with that in a 
text file then in step 1 add --schema to get just the table definition.

Then do pg_restore --data-only --table=tabletorecover -d recovery 
backup.backup as step 4.

>>
>> Andrus.
>>
>>
> 
> 


-- 
Adrian Klaver
adrian.klaver@aklaver.com



Re: How to get single table data from backup

От
Christoph Moench-Tegeder
Дата:
## Andrus (kobruleht2@hot.ee):

> This fails since tabletorecover contains lot foreign key references.

Check pg_restore options "--section=pre-data" and "--section=data" -
pre-data is the schema without indexes, contraints, etc. (those
would be in section post-data).

Regards,
Christoph

-- 
Spare Space



Re: How to get single table data from backup

От
Andrus
Дата:

Hi!

Geat answer since doesnt require manual sql editing. It worked.

Thank you.

Andrus.

19.12.2025 19:05 Christoph Moench-Tegeder kirjutas:
## Andrus (kobruleht2@hot.ee):

This fails since tabletorecover contains lot foreign key references.
Check pg_restore options "--section=pre-data" and "--section=data" -
pre-data is the schema without indexes, contraints, etc. (those
would be in section post-data).

Regards,
Christoph