Re: pg_upgrade diffs on WIndows

From: Andrew Dunstan <andrew(at)dunslane(dot)net>
To: Bruce Momjian <bruce(at)momjian(dot)us>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Subject: Re: pg_upgrade diffs on WIndows
Date: 2012-09-05 19:50:13
Message-ID: 5047ACF5.3040703@dunslane.net
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On 09/05/2012 03:40 PM, Bruce Momjian wrote:
> On Wed, Sep 5, 2012 at 03:17:40PM -0400, Andrew Dunstan wrote:
>>> The PG_BINARY_W change has only been verified on a non-buildfarm
>>> setup on my laptop (Mingw)
>>>
>>> Note that while it does look like there's a bug either in
>>> pg_upgrade or pg_dumpall, it's probably mostly harmless (adding
>>> some spurious CRs to function code bodies on Windows). I'd feel
>>> happier if it didn't, and happier still if I knew for sure the
>>> ultimate origin. Your pg_dumpall discovery above is interesting. I
>>> might have time later on today to delve into all this. I'm out of
>>> contact for the next few hours.
>>
>> OK, I now have a complete handle on what's going on here, and
>> withdraw my earlier statement that I am confused on this issue :-)
>>
>> First, one lot of CRs is produced because the pg_upgrade test script
>> calls pg_dumpall without -f and redirects that to a file, which
>> Windows kindly opens on text mode. The solution to that is to change
>> the test script to use pg_dumpall -f instead.
>>
>> The second lot of CRs (seen in the second dump file in the diff i
>> previously sent) is produced by pg_upgrade writing its output in
>> text mode, which turns LF into CRLF. The solution to that is the
>> patch to dump.c I posted, which, as Bruce observed, does the same
>> thing that pg_dumpall does. Arguably, it should also open the input
>> file in binary, so that if there really is a CRLF in the dump it
>> won't be eaten.
> So, right now we are only add \r for function bodies, which is mostly
> harmless, but what if a function body has strings with an embedded
> newlines? What about creating a table with newlines in its identifiers:
>
> CREATE TABLE "a
> b" ("c
> d" int);
>
> If \r is added in there, it would be a data corruption problem. Can you
> test that?

These are among the reasons why I am suggesting opening the file in
binary mode. You're right, that would be data corruption.

I can set up a check, but it will take a bit of time.

cheers

andrew

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