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<p class="MsoPlainText"><span style="color:black">Hi Karl,<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="color:black"><o:p> </o:p></span></p>
<p class="MsoPlainText"><span style="color:black">The Proj-rest node is indeed handling the WHERE clause.<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="color:black">If I simply count the number of rows in comms that satisfy WHERE c.active=1 AND c.comm_type=2 I get 745 as the QEP showed.<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="color:black"><o:p> </o:p></span></p>
<p class="MsoPlainText"><span style="color:black">Nonetheless I ran the query without the where clause. This changed the plan to a right join and the tuple counts are still weird.<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="color:black">See below.<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="color:black"><o:p> </o:p></span></p>
<p class="MsoPlainText">SELECT count(*)<o:p></o:p></p>
<p class="MsoPlainText">FROM comms c<o:p></o:p></p>
<p class="MsoPlainText"> LEFT JOIN researcher r ON c.launch_id = r.researcher_id AND c.launch_type in (0,2)<o:p></o:p></p>
<p class="MsoPlainText"> LEFT JOIN user_details ud ON ud.user_id = r.user_id<o:p></o:p></p>
<p class="MsoPlainText">Executing . . .<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">********************************************************************<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">QUERY PLAN 2,2, no timeout, of simple aggregate <o:p></o:p></p>
<p class="MsoPlainText"> aggregate expression -> count(*)<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText"><span style="font-family:"Courier New""> left join<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="font-family:"Courier New""> K Join(user_id)<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="font-family:"Courier New""> Heap<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="font-family:"Courier New""> Pages 2 Tups 786<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="font-family:"Courier New""> D161 C1279<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="font-family:"Courier New""> / \<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="font-family:"Courier New""> right join user_details<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="font-family:"Courier New""> Hash Join(researcher_id)(ud)<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="font-family:"Courier New""> Sort on(user_id) B-Tree(user_id)<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="font-family:"Courier New""> Pages 4 Tups 786 Pages 29 Tups 6200<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="font-family:"Courier New""> D109 C1248<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="font-family:"Courier New""> / \<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="font-family:"Courier New""> Proj-rest Proj-rest<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="font-family:"Courier New""> Sorted(NU) Sorted(NU)<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="font-family:"Courier New""> Pages 28 Tups 6117 Pages 221 Tups 52520<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="font-family:"Courier New""> D33 C61 D76 C525<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="font-family:"Courier New"">/ /<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="font-family:"Courier New"">researcher comms_launch_indx<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="font-family:"Courier New"">(r) I(c)<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="font-family:"Courier New"">B-Tree(NU) B-Tree(NU)<o:p></o:p></span></p>
<p class="MsoPlainText"><span style="font-family:"Courier New"">Pages 33 Tups 6117 Pages 305 Tups 52520<o:p></o:p></span></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText"><span style="color:black"><o:p> </o:p></span></p>
<p class="MsoPlainText">I wonder if that Kjoin tuple estimate is including the where clause as well, since the where restriction has to be applied somewhere, and the cost tree (QEP) doesn't normally show a separate proj-rest above joins. (Maybe it should!)
Do you still get 11 if you take the where clause off?<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">(although in this instance, the where restrictions can apply at the orig level, so maybe they're included at the proj-rest.)<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">Karl<o:p></o:p></p>
<p class="MsoPlainText"><o:p> </o:p></p>
<p class="MsoPlainText">_______________________________________________<o:p></o:p></p>
<p class="MsoPlainText">Info-ingres mailing list<o:p></o:p></p>
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<p class="MsoPlainText"><a href="http://lists.planetingres.org/mailman/listinfo/info-ingres"><span style="color:windowtext;text-decoration:none">http://lists.planetingres.org/mailman/listinfo/info-ingres</span></a><o:p></o:p></p>
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