Date: Mon, 21 May 2018 18:12:06 +0400
From: Abbas <abbas@rechat.com>
Subject: Re: Help me in reducing the CPU cost for the high cost query below,
 as it is hitting production seriously!!
To: pavan95 <pavan.postgresdba@gmail.com>
Cc: pgsql-performance@postgresql.org
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Sure thing. Base 60 or Sexagesimal is the numerical system used for 
measuring time (1 hour equals to 60 minutes and so on). But this case 
is even simpler, so without going into much detail about bases, you're 
mapping between two sets of numbers:

0 -> 0
.15 -> .25
.30 -> .50
.45 -> .75

 From working with clocks, we know that 15 minutes is .25 hours, 30 
minutes is .5 hours and so on. So you only need to divide the 
fractional part ( effort_hours - floor(effort_hours) ) by .6 to get 
what you want.

For example, let's say effort_hours = 1.15; then floor(1.15) is 1; so:

floor(1.15) + ( (1.15 - floor(1.15)) / 0.6 ) = 1 + ( (1.15 - 1) / 0.6 ) 
= 1 + ( 0.15 / 0.60 ) = 1.25

Hope it helps. Feel free to ask a question if it's still unclear. :)


On Mon, May 21, 2018 at 6:09 PM, pavan95 <pavan.postgresdba@gmail.com> 
wrote:
> Hi Abbas,
> 
> Thanks for your valuable suggestions. To my surprise I got the same 
> output
> as what I have executed before.
> 
> But unfortunately I'm unable to understand the logic of the code, in
> specific what is base 60 number? The used data type for "effort_hours"
> column is 'double precision'.
> 
> Kindly help me in understanding the logic. Thanks in advance.
> 
> Regards,
> Pavan
> 
> 
> 
> --
> Sent from: 
> http://www.postgresql-archive.org/PostgreSQL-performance-f2050081.html
> 


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<div>Sure thing. Base 60 or Sexagesimal is the numerical system used for measuring time (1 hour equals to 60 minutes and so on). But this case is even simpler, so without going into much detail about bases, you're mapping between two sets of numbers:</div><div><br></div><div>0 -&gt; 0</div><div>.15 -&gt; .25</div><div>.30 -&gt; .50</div><div>.45 -&gt; .75</div><div><br></div><div>From working with clocks, we know that 15 minutes is .25 hours, 30 minutes is .5 hours and so on. So you only need to divide the fractional part ( effort_hours - floor(effort_hours) ) by .6 to get what you want.</div><div><br></div><div>For example, let's say effort_hours = 1.15; then floor(1.15) is 1; so:</div><div><br></div><div>floor(1.15) + ( (1.15 - floor(1.15)) / 0.6 ) = 1 + ( (1.15 - 1) / 0.6 ) = 1 + ( 0.15 / 0.60 ) = 1.25</div><div><br></div><div>Hope it helps. Feel free to ask a question if it's still unclear. :)</div><div><br></div><br>

On Mon, May 21, 2018 at 6:09 PM, pavan95 &lt;pavan.postgresdba@gmail.com&gt; wrote:<br>
<blockquote type="cite"><div class="plaintext" style="white-space: pre-wrap;">Hi Abbas,

Thanks for your valuable suggestions. To my surprise I got the same output
as what I have executed before. 

But unfortunately I'm unable to understand the logic of the code, in
specific what is base 60 number? The used data type for "effort_hours"
column is 'double precision'. 

Kindly help me in understanding the logic. Thanks in advance.

Regards,
Pavan


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Sent from: <a href="http://www.postgresql-archive.org/PostgreSQL-performance-f2050081.html">http://www.postgresql-archive.org/PostgreSQL-performance-f2050081.html</a>

</div></blockquote><br><br>

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