RE: Timeout parameters

Hello Robert-san.

> From: Robert Haas <robertmhaas@gmail.com>
> So this says that it works on systems that have TCP_USER_TIMEOUT or an
> equivalent socket option and that it also works on Windows, and then a few lines
> later....
> 
> +       This parameter is not supported on Windows, and must be zero.
> 
> This says it actually doesn't work on Windows.
It has been pointed out by Fabien-san before and it has not been corrected yet.
I am very sorry for making "needs review" even though I have not reposted the patch.

> I think the language about an equivalent socket option isn't helpful.
> We should document any equivalents we actually support, and not say anything
> about anything else.
Does it mean that doc explain with words "setsockopt()" and/or its option "TCP_USER_TIMEOUT" ?
BTW, This sentence is to be consistent with the keepalive description e.g., [1].
In my opinion, if this doc need to be changed, we should change docs about keepalive too.
How do you think?

> +       To enable full control under TCP connection use this option
> together with
> +       keepalive.
> That doesn't tell me anything useful.
Oh, I see. Indeed, this is not about postgres but general network.

> 
> 
> +        Specify in milliseconds the time to disconnect to the client
> +        when there is no ack packet from the client to the server's
> data transmission.
> +        This parameter is supported on linux version 2.6.37 or later.
> 
> Hmm.  This looks like a second, and broadly better, definition of the parameter.
> Now we have a different definition of where it's supported.  This is the THIRD
> attempt to tell me which platforms are supported -- just Linux, 2.6.37 or greater.
> 
> +         This parameter is not supported on Windows.
> 
> And then, in case I missed the last three attempts to tell me about platform
> support, there's this.
I intended to delete these sentences. I'll delete it.

> Have you checked whether this can be easily supported on FreeBSD and/or
> NetBSD?
No, not yet. Checked red hat enterprise linux only...
Indeed, I should have checked on some UNIX OS.

[1] https://www.postgresql.org/docs/current/runtime-config-connection.html
Best regards,
---------------------
Ryohei Nagaura