hi,<br><br>why dont you check the performance of your code against the built-in min function of SQL and see the differences? <br><br>in general to answer your question, if your system has &quot;cold&quot; memory, it will read the bat from disk, after that it will have warm memory and should find everything in memory unless th column is to big to fit in memory. iostat is your friend here.<br>
<br><div class="gmail_quote">On Sun, Dec 2, 2012 at 11:40 AM, Martin Kersten <span dir="ltr">&lt;<a href="mailto:Martin.Kersten@cwi.nl" target="_blank">Martin.Kersten@cwi.nl</a>&gt;</span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi,<br>
<br>
Good to hear that you have fun in diving into a very large code base.<div class="im"><br>
<br>
On 12/2/12 10:35 AM, swapnil joshi wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi<br>
<br>
         I have done some fun with Monetdb. i have created my own user<br>
define xmin function.<br>
objective of that function is find minimum value from specific column.<br>
<br>
I have writen some code as follow :<br>
</blockquote></div>
...<div class="im"><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
  //****************************<u></u>******************************<u></u>******************************<u></u>*********/<br>
<br>
when i am executing following SQL statement then it will give result but<br>
it takes 10 to 13 seconds<br>
I know where i am executing on single core of CPU but when i executing<br>
that above statement<br>
then, I think it will taking data from disk because disk access<br>
indicator led blow when i executing<br>
that above SQL statement. means, It was not using system main memory.<br>
<br>
I will be wrong.<br>
<br>
Can each time it is accessing BAT from disk or from main memory?<br>
</blockquote></div>
All disk IO is transparently handled by the OS, i.e. see memorymapped<br>
file semantics. IO can be triggered both by MonetDB or indirectly<br>
by other programs competing with your memory resources, e.g.<br>
webbrowsers with heavy Flash scripts.<br>
A first impression of the numbers indicate this might be the case.<div class="im"><br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Can you test me Program ?<br>
</blockquote></div>
We don&#39;t have the time/resources to test third party experimental code,<br>
which does not lead to major functional/bugfix/performance improvements<br>
of the MonetDB source code.<br>
<br>
regards, Martin<br>
<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">
--<br>
Regards,<br>
Swapnil K. Joshi<br>
<br>
<br>
<br></div>
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