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From Dave Birdsall <dave.birds...@esgyn.com>
Subject Re: how to read debug info after set SUBQUERY_UNNESTING to 'debug'
Date Sun, 28 Jan 2018 18:49:12 GMT
Hi Ming,


I don't know the particulars of that CQD.


However, have you used the DISPLAY utility? That shows the shape of the query tree after each
pass of the compiler. So you will be able to see what pass transforms a subquery into a join.


Dave

________________________________
From: Liu, Ming (Ming) <ming.liu@esgyn.cn>
Sent: Sunday, January 28, 2018 12:58:22 AM
To: dev@trafodion.apache.org
Subject: how to read debug info after set SUBQUERY_UNNESTING to 'debug'

hi, all,

I am trying to understand better about subquery optimization in Trafodion. So I set the SUBQUERY_UNNESTING
CQD to 'DEBUG', and try a few queries, but I don't know how to see the output of that DEBUG?
I saw the code will generate some WARNs into diagArea, but not seeing them.
If someone know how to use this debug skill, please help me.

thanks,
Ming

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