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<DIV dir=ltr align=left><SPAN class=792582304-25012008><FONT face=Verdana
color=#000080 size=2>Matt,</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=792582304-25012008><FONT face=Verdana
color=#000080 size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=792582304-25012008><FONT face=Verdana
color=#000080 size=2>That rationale is useful - thanks.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=792582304-25012008><FONT face=Verdana
color=#000080 size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=792582304-25012008><FONT face=Verdana
color=#000080 size=2>Did you try against Teradata? I am a little hazy on what
combinations of grouping sets/distinct-count/AJIs they support, but it's
possible that distinct-count + grouping sets may prevent usage of an AJI, and
that would be unfortunate because AJIs give a big boost to
performance.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=792582304-25012008><FONT face=Verdana
color=#000080 size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=792582304-25012008><FONT face=Verdana
color=#000080 size=2>You didn't answer my 2nd question: <SPAN><FONT face=Verdana
color=#000080 size=2>Would this work with distinct-count measures applied to
aggregate members? (For example unit sales over [CA plus
OR].)</FONT></SPAN></FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=792582304-25012008><FONT face=Verdana
color=#000080 size=2><SPAN></SPAN></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=792582304-25012008><FONT face=Verdana
color=#000080 size=2><SPAN>Julian</SPAN></FONT></SPAN></DIV><BR>
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<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B> mondrian-bounces@pentaho.org
[mailto:mondrian-bounces@pentaho.org] <B>On Behalf Of </B>Matt
Campbell<BR><B>Sent:</B> Thursday, January 24, 2008 7:38 AM<BR><B>To:</B>
jhyde@pentaho.org; Mondrian developer mailing list<BR><B>Subject:</B> Re:
[Mondrian] Adding Grouping Set support for Distinct Count
measures<BR></FONT><BR></DIV>
<DIV></DIV>We're interested in this change not so much for performance
(although we have seen some cases where it seems to improve performance) but
because:<BR><BR>1) It will allow correct totaling in cases where a dimension
table does not join to every fact table row. We can get over-counting in
these cases because the total query is fired separately without joining to the
dimension table. I know in general dimension rows should be
all-inclusive, ie have a member value for each fact table row. We have
some good reasons for violating this rule, though. <BR><BR>2) It will also
bring greater consistency to how count distinct and summable measures are
evaluated.<BR><BR><BR><BR>
<DIV class=gmail_quote>On Jan 22, 2008 7:52 PM, Julian Hyde <<A
href="mailto:jhyde@pentaho.org"> jhyde@pentaho.org</A>> wrote:<BR>
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<DIV>
<DIV dir=ltr align=left><SPAN><FONT face=Verdana color=#000080 size=2>No
objections in principle. Have you hand-generated such queries to see whether
they are any improvement? It is possible that the queries do not yield any
performance improvement, because distinct-count is difficult for a database
to evaluate and therefore it might be difficult for the DBMS to find
commonality between the different grouping sets.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN><FONT face=Verdana color=#000080
size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN><FONT face=Verdana color=#000080 size=2>Would
this work with distinct-count measures applied to aggregate members? (For
example unit sales over [CA plus OR].)</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN><FONT face=Verdana color=#000080
size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN><FONT face=Verdana color=#000080
size=2>Julian</FONT></SPAN></DIV><BR>
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style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: rgb(0,0,128) 2px solid; MARGIN-RIGHT: 0px">
<DIV lang=en-us dir=ltr align=left>
<HR>
<FONT face=Tahoma size=2><B>From:</B> <A
href="mailto:mondrian-bounces@pentaho.org"
target=_blank>mondrian-bounces@pentaho.org</A> [mailto:<A
href="mailto:mondrian-bounces@pentaho.org"
target=_blank>mondrian-bounces@pentaho.org</A>] <B>On Behalf Of </B>Ajit
Vasudeo Joglekar<BR><B>Sent:</B> Tuesday, January 22, 2008 9:33
AM<BR><B>To:</B> <A href="mailto:mondrian@pentaho.org"
target=_blank>mondrian@pentaho.org</A><BR><B>Subject:</B> [Mondrian]
Adding Grouping Set support for Distinct Count
measures<BR></FONT><BR></DIV>
<DIV>
<DIV></DIV>
<DIV class=Wj3C7c>
<DIV></DIV><BR><FONT face=sans-serif size=2>We would like to introduce
grouping sets support for distinct count measures in mondrian. We have
analyzed this and it is a small change. Most of the work is around
changing and adding test cases.</FONT> <BR><BR><FONT face=sans-serif
size=2>It will be great if we can make this a part of the upcoming
release. Requesting comments</FONT> <BR><BR><FONT face=sans-serif
size=2>Thanks</FONT> <BR><BR><FONT face=sans-serif size=2>-Ajit</FONT>
<BR><BR></DIV></DIV></BLOCKQUOTE></DIV><BR>_______________________________________________<BR>Mondrian
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