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Re: pipe chunking vs Windows

From: Andrew Dunstan <andrew(at)dunslane(dot)net>
To: Magnus Hagander <magnus(at)hagander(dot)net>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: pipe chunking vs Windows
Date: 2007-07-29 15:36:58
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-hackers

Magnus Hagander wrote:
> Andrew Dunstan wrote:
>> I have just discovered that the recently implemented pipe chunking
>> protocol is broken on Windows. This is because the pipes are operating
>> in text mode and doing LF->CR-LF translation, so the number of bytes
>> received is not the number transmitted and set in the protocol header.
>> I have not yet succeeded in turning this behaviour off (_setmode()
>> didn't seem to affect it). If we can't find a way to turn it off, the
>> only solution short of abandoning its use on Windows that I can think of
>> is to translate LF on input to something unlikely like 0x1C and then
>> translate it back when we read it from the pipe.
> At what point does it actually do the translation? Meaning what
> system/library call has it?
> Are we using the pipes from src/port/pipe.c? It does sound a bit weird
> that they'd do that, since it's basically just emulating stuff over
> standard tcp sockets, but perhaps something is broken in that code?
> Sorry, haven't really checked up on the chunk code yet, so I don't know
> offhand where to look.

It looks like we aren't. In fact. it looks like the only call to 
pgpipe() in the whole source tree is in the syslogger and it's in 
specifically non-Windows code, meaning that that whole file is currently 

Maybe you should have a good look at src/backend/postmaster/syslogger.c. 
If we could get rid of the pipe-read threads and all the special Windows 
cruft there that would certainly be an advance.



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