Re: SO_SNDBUF size is small on win32? - Mailing list pgsql-hackers

From Andrew Dunstan
Subject Re: SO_SNDBUF size is small on win32?
Date
Msg-id 44A152B1.1020302@dunslane.net
Whole thread Raw
In response to Re: SO_SNDBUF size is small on win32?  (Martijn van Oosterhout <kleptog@svana.org>)
Responses Re: SO_SNDBUF size is small on win32?  (Martijn van Oosterhout <kleptog@svana.org>)
Re: SO_SNDBUF size is small on win32?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Martijn van Oosterhout wrote:

>On Wed, Jun 28, 2006 at 12:23:13AM +0900, Yoshiyuki Asaba wrote:
>  
>
>>Hi,
>>
>>I see a performance issue on win32. This problem is causes by the
>>following URL. 
>>
>>http://support.microsoft.com/kb/823764/EN-US/
>>
>>On win32, default SO_SNDBUF value is 8192 bytes. And libpq's buffer is
>>8192 too.
>>    
>>
>
>Ok, so there's a difficiency in Windows TCP code. Do you have any
>benchmarks to show this actually makes a difference. According to the
>URL you give, the problem occurs if the libpq buffer is *bigger* than
>the socket buffer, which it isn't...
>  
>

No, it says it occurs if this condition is met: "A single *send* call or 
*WSASend* call fills the whole underlying socket send buffer."

This will surely be true if the buffer sizes are the same. They 
recommend making the socket buffer at least 1 byte bigger.

cheers

andrew




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