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<p class=MsoPlainText>Hi Steve,<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Use HELP TABLE to make sure the statistics are recorded
against the columns in the SELECT and WHERE clause.<o:p></o:p></p>
<p class=MsoPlainText style='margin-left:36.0pt'>sql db1 <<eof >
db1.txt<o:p></o:p></p>
<p class=MsoPlainText style='margin-left:36.0pt'>help table tablename \g\q<o:p></o:p></p>
<p class=MsoPlainText style='margin-left:36.0pt'>eof<o:p></o:p></p>
<p class=MsoPlainText style='margin-left:36.0pt'><o:p> </o:p></p>
<p class=MsoPlainText style='margin-left:36.0pt'>sql db2 <<eof >
db2.txt<o:p></o:p></p>
<p class=MsoPlainText style='margin-left:36.0pt'>help table tablename \g\q<o:p></o:p></p>
<p class=MsoPlainText style='margin-left:36.0pt'>eof<o:p></o:p></p>
<p class=MsoPlainText style='margin-left:36.0pt'><o:p> </o:p></p>
<p class=MsoPlainText style='margin-left:36.0pt'>diff db1.txt db2.txt<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Double check all tables and indexes from the query are
configured the same: column data type, page size, storage, primary keys,
foreign key constraints.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Run optimizedb -zc -zk dbname -rtablename <o:p></o:p></p>
<p class=MsoPlainText>Run statdump dbname -rtablename<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Does the QEP show a timeout?<o:p></o:p></p>
<p class=MsoPlainText>Compare the configuration of the servers: <o:p></o:p></p>
<p class=MsoPlainText>degree_of_parallelism<o:p></o:p></p>
<p class=MsoPlainText>opf_hash_aggregate<o:p></o:p></p>
<p class=MsoPlainText>opf_hash_join <o:p></o:p></p>
<p class=MsoPlainText>opf_greedy_factor<o:p></o:p></p>
<p class=MsoPlainText>opf_joinop_timeout<o:p></o:p></p>
<p class=MsoPlainText>qflatten_aggregate<o:p></o:p></p>
<p class=MsoPlainText>qflatten_singleton<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Perhaps send a copy of the select and QEPs. <o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Paul<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 lang=EN-US>-----Original Message-----<br>
From: info-ingres-bounces@lists.planetingres.org [mailto:info-ingres-bounces@lists.planetingres.org]
On Behalf Of s.anderson.au@gmail.com<br>
Sent: Thursday, 15 August 2019 10:48 AM<br>
To: info-ingres@lists.planetingres.org<br>
Subject: [Info-ingres] Comparing QEPs</span><o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Hi there<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Had an issue where a query in one ABF screen started
running very slowly, instead of completing instantly, it now takes twenty
seconds.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Re-generating the statistics for the associated tables
did not help.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>As such I copied the tables to our dev box and compared
the query plans Ingres created on dev vs production. On production the QEP did
not utilise a secondary index, whereas on dev it did.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>The dev vs production is not a perfection comparison as
in the process of copying the tables across to dev, the tables were rebuilt.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>I tried to force Ingres to use the secondary index by
tweaking the query to explicitly join with the secondary index, but my hack did
not help.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>What is the best approach for this situation? Should I be
rebuilding the tables involved?<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Thanks<o:p></o:p></p>
<p class=MsoPlainText>Steve<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>
<p class=MsoPlainText>Info-ingres@lists.planetingres.org<o:p></o:p></p>
<p class=MsoPlainText>https://lists.planetingres.org/mailman/listinfo/info-ingres<o:p></o:p></p>
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