Re: Statistics Import and Export

>
> Also, we will need to think through the set of pg_dump options again. A
>> lot of our tools seem to assume that "if it's the default, we don't
>> need a way to ask for it explicitly", which makes it a lot harder to
>> ever change the default and keep a coherent set of options.
>>
>
> That's a good point in general, and definitely something we should think
> through, independently of his patch.
>

I agree. There was a --with-statistics option in earlier patchsets, which
was effectively a no-op because statistics are the default, and it was
removed when its existence was questioned. I mention this only to say that
consensus for those options will have to be built.

> FWIW, I've seen many cases of people using automated tools to verify the
> *schema* between two databases. I'd say that's quite common. But they use
> pg_dump -s, which I believe is not affected by this one.
>

Correct, -s behaves as before, as does --data-only. Schema, data, and
statistics are independent, each has their own -only flag, each each has
their own --no- flag.

If you were using --no-schema to mean data-only, or --no-data to mean
schema-only, then you'll have to add --no-statistics to that call, but I'd
argue that they already had a better option of getting what they wanted.

If you thought you saw major changes in the patchsets around those flags,
you weren't imagining it. There was a lot of internal logic that worked on
the assumptions like "If schema_only is false then we must want data" but
that's no longer strictly true, so we resolved all the user flags to
dumpSchema/dumpData/dumpStatistics at the very start, and now the internal
logic work is based on those affirmative flags rather than the bankshot
absence-of-the-opposite logic that was there before.

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