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Re: 500 times slower

From: Karol Szkudlarek <karol(at)mikronika(dot)com(dot)pl>
To: Dave Page <dpage(at)vale-housing(dot)co(dot)uk>
Cc: pgsql-odbc(at)postgresql(dot)org
Subject: Re: 500 times slower
Date: 2005-02-09 14:06:11
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-odbc
Dave Page wrote:
> Err, no neither am I. Why do you think it's got something to do with
> Nagle/delayed ACKs?
> The only thing that instantly rings bells for me is that the max size of
> a text field is 8190 bytes at present (which really should be increased,
> if not removed altogether), which won't fit in the default buffer. But
> then, I wouldn't expect to see the performance drop you describe with a
> 4096 byte buffer, only one much smaller.
> Anyone else got any ideas?
> Regards, Dave

Hi Dave!

In my test case I read LOB of 10 megabytes size.
So then in the function (with 4kB SOCK_BUFFER_SIZE):
	SOCK_get_next_byte(SocketClass *self)
below line (socket.c):

self->buffer_filled_in = recv(self->socket, (char *) self->buffer_in, 
self->buffer_size, 0);

runs in the following schema: 0msec, 200msec, 0msec, 200msec... etc.
So above times suggest delayed ACK timer (200msec).


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