Re: raw output from copy

From: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Andrew Dunstan <andrew(at)dunslane(dot)net>, Simon Riggs <simon(at)2ndquadrant(dot)com>, Pavel Golub <pavel(at)microolap(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: raw output from copy
Date: 2015-07-06 21:34:20
Message-ID: CAFj8pRCbsZM3ubjB3VjqhxwvfUw8TkaZA1VvcSTebRZkqvvH4g@mail.gmail.com
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Hi

here is a version with both direction support.

postgres=# copy foo from '/tmp/1.jpg' (format raw);
COPY 1
Time: 93.021 ms
postgres=# \dt+ foo
List of relations
┌────────┬──────┬───────┬───────┬────────┬─────────────┐
│ Schema │ Name │ Type │ Owner │ Size │ Description │
╞════════╪══════╪═══════╪═══════╪════════╪═════════════╡
│ public │ foo │ table │ pavel │ 256 kB │ │
└────────┴──────┴───────┴───────┴────────┴─────────────┘
(1 row)

postgres=# \copy foo to '~/3.jpg' (format raw)
COPY 1
Time: 2.401 ms

Regards

Pavel

2015-07-02 17:02 GMT+02:00 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>:

> Andrew Dunstan <andrew(at)dunslane(dot)net> writes:
> > Does the COPY line protocol even support binary data?
>
> The protocol, per se, just transmits a byte stream. There is a field
> in the CopyInResponse/CopyOutResponse messages that indicates whether
> a text or binary copy is being done. One thing we'd have to consider
> is whether "raw" mode is sufficiently different from binary to justify
> an additional value for this field, and if so whether that constitutes
> a protocol break.
>
> IIRC, psql wouldn't really care; it just transfers the byte stream to or
> from the target file, regardless of text or binary mode. But there might
> be other client libraries that are smarter and expect "binary" mode to
> mean the binary file format specified in the COPY reference page. So
> there may be value in being explicit about "raw" mode in these messages.
>
> A key point in all this is that people who need "raw" transfer probably
> need it in both directions, a point that your SELECT proposal cannot
> satisfy, but hacking COPY could. So I lean towards the latter really.
>
> regards, tom lane
>

Attachment Content-Type Size
copy-raw-format-20150706-01.patch text/x-patch 22.0 KB

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