From: Tom Lane <tgl@sss.pgh.pa.us>
To: Heikki Linnakangas <hlinnaka@iki.fi>
cc: pgsql-hackers@postgreSQL.org
Subject: Re: Receive buffer size for the statistics socket
In-reply-to: <0a77466f-408d-ad7e-46c7-2efae718c4d3@iki.fi>
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 <0a77466f-408d-ad7e-46c7-2efae718c4d3@iki.fi>
Comments: In-reply-to Heikki Linnakangas <hlinnaka@iki.fi>
	message dated "Mon, 15 May 2017 12:34:38 +0300"
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Date: Mon, 15 May 2017 10:07:08 -0400
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Heikki Linnakangas <hlinnaka@iki.fi> writes:
> On 05/14/2017 09:54 PM, Tom Lane wrote:
>> A further idea is that maybe backends should be tweaked to avoid
>> blasting large amounts of data at the stats collector in one go.
>> That would require more thought to design, though.

> The data is already sent in small < 1 kB messages, I don't see what more 
> we can do in the sender side to avoid overwhelming the receiver. Except 
> reduce the amount of data sent overall. But that only goes so far, we 
> cannot eliminate the problem altogether, unless we also lose some detail.

I was wondering about some sort of rate-throttling on the messages.
For instance, stop after sending X kilobytes, leaving remaining counts
to be sent at the next opportunity.  (Although it's not clear if you'd
ever catch up :-(.)  Or just a short sleep after every X kilobytes, to
make it more probable that the stats collector gets to run and collect
the data.

			regards, tom lane


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