Re: pg_dump / copy bugs with "big lines" ?

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: pg_dump / copy bugs with "big lines" ?
Date: 2016-03-02 15:23:13
Message-ID: 21331.1456932193@sss.pgh.pa.us
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Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com> writes:
> On 03/02/2016 03:18 PM, Daniel Verite wrote:
>> However, getting it to the client with \copy big2 to 'file'
>> still produces the error in psql:
>> lost synchronization with server: got message type "d"
>> and leaves an empty file, so there are more problems to solve to
>> go beyond 2GB text per row.

> My guess is this is a problem at the protocol level - the 'd' message is
> CopyData, and all the messages use int32 to define length. So if there's
> a 2GB row, it's likely to overflow.

I'm too lazy to check the exact wording, but I don't think there's a hard
and fast promise in the protocol doc that one CopyData message == one row.
So we could probably subdivide a very wide line into multiple messages.

regards, tom lane

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