|From:||Alfred Perlstein <bright(at)wintelcom(dot)net>|
|To:||Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>|
|Subject:||Re: COPY BINARY is broken...|
|Views:||Raw Message | Whole Thread | Download mbox|
* Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> [001201 14:42] wrote:
> I've just noticed that COPY BINARY is pretty thoroughly broken by TOAST,
> because what it does is to dump out verbatim the bytes making up each
> tuple of the relation. In the case of a moved-off value, you'll get
> the toast reference, which is not going to be too helpful for reloading
> the table data. In the case of a compressed-in-line datum, you'll at
> least have all the data there, but the COPY BINARY reader will crash
> and burn when it sees it.
> Fixing this while retaining backwards compatibility with the existing
> COPY BINARY file format is possible, but it seems rather a headache:
> we'd need to detoast all the toasted columns, then heap_formtuple a
> new tuple containing the expanded data, and finally write that out.
> (Can't do it on a field-by-field basis because the file format requires
> the total tuple size to precede the tuple data.) Kind of ugly.
> The existing COPY BINARY file format is entirely brain-dead anyway; for
> example, it wants the number of tuples to be stored at the front, which
> means we have to scan the whole relation an extra time to get that info.
> Its handling of nulls is bizarre, too. I'm thinking this might be a
> good time to abandon backwards compatibility and switch to a format
> that's a little easier to read and write. Does anyone have an opinion
> pro or con about that?
BINARY COPY scared the bejeezus out of me, anyone using the interface
is asking for trouble and supporting it seems like a nightmare, I
would rip it out.
-Alfred Perlstein - [bright(at)wintelcom(dot)net|alfred(at)freebsd(dot)org]
"I have the heart of a child; I keep it in a jar on my desk."
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