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Message-ID: <468E7CAB.9070802@enterprisedb.com>
Date: Fri, 06 Jul 2007 18:32:27 +0100
From: Heikki Linnakangas <heikki@enterprisedb.com>
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To: Jan Wieck <JanWieck@Yahoo.com>
CC: Peter Eisentraut <peter_e@gmx.net>,  pgsql-hackers@postgresql.org
Subject: Re: usleep feature for pgbench
References: <468D42B3.4010701@Yahoo.com> <200707061644.57878.peter_e@gmx.net>
	<468E7AC3.3040501@Yahoo.com>
In-Reply-To: <468E7AC3.3040501@Yahoo.com>
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Jan Wieck wrote:
> On 7/6/2007 10:44 AM, Peter Eisentraut wrote:
>> Am Donnerstag, 5. Juli 2007 21:12 schrieb Jan Wieck:
>>> To test some changes in Slony I needed a
>>>
>>>      \usleep [microseconds|:variable]
>>>
>>> in pgbench's scripting language to be able to have hundreds of
>>> concurrent running transactions without totally swamping the system. I
>>> was wondering if anyone would object to permanently adding this to the
>>> pgbench code?
>>
>> Or maybe a \sleep command that takes units, if it's not too much work.
>>
> 
> You mean as a second, optional argument? Good idea.
> 
>   us = microseconds
>   ms = milliseconds
>   s  = seconds (default)
> 
>   \sleep {value|:variable} [us|ms|s]
> 
> Is that okay with everyone?

I won't object, but is it really worth the trouble?

Can you do microsecond precision sleeps, and on what platforms? How much 
overhead is there? IIRC, on Linux the minimum time you can sleep depends 
on CONFIG_HZ, and the default was 10 ms until recently.

-- 
   Heikki Linnakangas
   EnterpriseDB   http://www.enterprisedb.com