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Re[2]: sequence numbers

From: <dgoulet_at_vicr.com>
Date: Thu, 10 Oct 2002 14:18:59 -0800
Message-ID: <F001.004E6499.20021010141859@fatcity.com>


Actually there is no IO penalty since Oracle has to treat the sequence just like any table with the old LRU algorithm. I have several sequences with a cache of 0 and they perform as well as those with a cache value. The big difference is when you shut down the database and all of those cached values end up in the trash.

Dick Goulet

____________________Reply Separator____________________
Author: "Yechiel Adar" <adar76_at_inter.net.il>
Date:       10/10/2002 1:38 PM

I think that you will have an update to the sequence number EVERY time instead of every 20 times. That's mean I/o for every nextval.

Yechiel Adar
Mehish

  CACHE 20 is the default, so if you remove the clause, it will have absolutely no impact on performance or anything else...    

  ...of course, I get the feeling that that wasn't the gist of your question, was it?

    I have been given create scripts for sequences to be used in tables that will be loaded via bulk loads. How huge is the potential performance hit if I take out the cache 20?

    April Wells
    Oracle DBA
    There is neither good nor bad, but thinking makes it so. -Shakespeare

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style="FONT: 10pt Times New Roman; MARGIN-LEFT: 2px; MARGIN-TOP: 2px"> <DIV><FONT face=Arial size=3>I think that you will have an update to the sequence number EVERY time instead of every 20 times. That's mean I/o for every nextval.</FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV>Yechiel Adar<BR>Mehish</DIV>
<BLOCKQUOTE dir=ltr 

style="BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV

  style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A href="mailto:Tim_at_SageLogix.com" title=Tim_at_SageLogix.com>Tim Gorman</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A href="mailto:ORACLE-L_at_fatcity.com"

  title=ORACLE-L_at_fatcity.com>Multiple recipients of list ORACLE-L</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, October 10, 2002 7:43
  PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: sequence numbers</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial>CACHE 20 is the default, so if you remove the clause, it

  will have absolutely no impact on performance or anything else...</FONT></DIV>
<DIV><FONT face=Arial></FONT>&nbsp;</DIV>
<DIV><FONT face=Arial>...of course, I get the feeling that that wasn't the
  gist of your question, was it?</FONT></DIV>
<BLOCKQUOTE dir=ltr

  style="BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">

    <DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>     <DIV
    style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>

    <A href="mailto:awells_at_csedge.com" title=awells_at_csedge.com>April Wells</A> 
    </DIV>
    <DIV style="FONT: 10pt arial"><B>To:</B> <A 
    href="mailto:ORACLE-L_at_fatcity.com" title=ORACLE-L_at_fatcity.com>Multiple     recipients of list ORACLE-L</A> </DIV>     <DIV style="FONT: 10pt arial"><B>Sent:</B> Wednesday, October 09, 2002 8:54     AM</DIV>
    <DIV style="FONT: 10pt arial"><B>Subject:</B> sequence numbers</DIV>
    <DIV><BR></DIV>
    <DIV><SPAN class=841194713-09102002>I have been given create scripts for 
    sequences to be used in tables that will be loaded via bulk loads.&nbsp; How

    huge is the potential performance&nbsp;hit if I take out the cache     20?</SPAN></DIV>
    <DIV>&nbsp;</DIV>
    <P><FONT face="Courier New">April Wells</FONT> <BR><FONT     face="Courier New">Oracle DBA&nbsp;</FONT><BR><SPAN     class=841194713-09102002><FONT face="Courier New">T<SPAN     class=841194713-09102002>here is neither good nor bad, but thinking makes it

    so.
-Shakespeare</SPAN></FONT></SPAN></P></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>

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Received on Thu Oct 10 2002 - 17:18:59 CDT

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