Re: Invalid field size

Moreno Andreo <moreno(dot)andreo(at)evolu-s(dot)it> writes:
> I've implemented a backup procedure in C# with Npgsql (using COPY TO I
> dump all tables in a compressed file) that's been working well in the
> last 5 years (and it's still working, since this is a single, isolated
> case).
> OS: Windows 7
> PG: 9.1.6 (I know, it's EOL, but I think it's not matter here)
> [ got corrupted data with: ]
> 2017-07-04 12:55:27 CEST STATEMENT: COPY
> tab(cod,guid,data,blob,thumbnail,descr,type,url,user,home,codrec,table,op,dagg,last)
> FROM STDIN WITH BINARY

Pushing binary data around on Windows is always a hazardous proposition.
I'd bet something somewhere did a newline format conversion on your
data, either adding or removing CR characters. There might not have
been any CR or LF bytes in the data fields proper, but it'd be quite
plausible for some of the length words used in binary-COPY format to
contain such bytes.

You might be better off using plain text COPY format; it can withstand
this sort of thing much better.

regards, tom lane