Re: db partial dumping with pg_dump

On Tue, 13 Aug 2002, Tom Lane wrote:

> This patch seems extremely messy to me.  Unless I'm missing something,
> -w just plain fails except when you are dumping a specific table (ie,
> -t must be given as well).  And heaven help you if you specify a
> different table in -t than the one -w is selecting from.  This isn't
> well thought out.

You're right. The patch I've sent was no way for submitting to sources !
I just asked about the feature and attached to message for Rod Taylor.

>
> I'm not at all convinced that such a thing belongs in pg_dump anyway.
> It'd be more useful as a manually-invokable feature, I think.  You
> can almost do this in psql with
>     select * from table where something
>     \g outfile
> but I don't think you can get psql to emit the data in a form that can
> be reloaded reliably (it won't quote data characters that look the same
> as column delimiters, for instance).
>

that was the reason we don't use psql for dumping


> What would seem to make sense is adding a WHERE-clause option to
> COPY TO, and then you could go
>     COPY table TO 'myfile' WHERE ...
> We already have column-list support in COPY, so we can already slice the
> table vertically --- WHERE would let you slice it horizontally, which
> seems a natural extension.  (BTW, has anyone taught psql's \copy about
> column lists?  AFAIR the original patch was only against the backend.)
>
> I'm finding it hard to visualize situations where I'd want the extra
> baggage of pg_dump for something like this.  If I want the schema at
> all, I'll probably want it separate from the data so that I can hack
> the schema conveniently --- so I'd want to do a "pg_dump -s -t table"
> and then do the selective copying separately.
>

that'd be nice ! I often need such a feature because db at work are often
too large to play at home :-)


>             regards, tom lane
>
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Regards,    Oleg
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Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
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