Re: backup and restore questions

Dear Sally Sally ,

> I had a few questions concerning the backup/restore process for pg.
>
> 1) Is it possible to dump data onto an existing database that contains
> data (assumning the schema of both are the same). Has anyone done
> this? I am thinking of this in order to expediate the data load process

This can work provided the database are on same system and have have
same schema  not tried though.

>
> 2) I read that when dumping and restoring data the insert option is
> safer but slower than copy? Does anyone know from experience how much
> slower (especially for a database containing millions of records).

If  you are real serious about your data best way AFAIK is insert
because with insert statments you can move around in case
you upgrade your database or add a new colum in new table  but trying to
restore a old  data of the same table.
On an
Celeron 900
PostgreSQL 7.3.4
RH 9.0
a 151Kb tared backup takes about 5 Minutes.
Though data restore depends 99 % on disk throughput 1% on CPU  in case
of plain insert file
and  90 % on disk throughput and 10 % CPU in case of tared file.

>
> 3) can pg_restore accept a file that is not archived like a zipped
> file or plain text file (file.gz or file)

Can use both zipped and Plain. New versions of pg_restore i.e 7.3 >
identify the file format automatically

>
> 4) Is the general practise to have one whole dump of a database or
> several separate dumps (by table etc...)?

One dump for  data and other dump for schema will always help.

--
Regards,
Vishal Kashyap
Director / Lead Developer,
Sai Hertz And Control Systems Pvt Ltd,
http://saihertz.rediffblogs.com
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