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https://issues.apache.org/jira/browse/TRAFODION-3192?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16596661#comment-16596661
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Sandhya Sundaresan commented on TRAFODION-3192:
-----------------------------------------------

|an old email showing other queue resizing:
From: Eric Owhadi 
Sent: Monday, September 11, 2017 3:25 PM
To: Sandhya Sundaresan 
<[sandhya.sundare...@esgyn.com|mailto:sandhya.sundare...@esgyn.com]>; Hans 
Zeller <[hans.zel...@esgyn.com|mailto:hans.zel...@esgyn.com]>; Suresh Subbiah 
<[suresh.subb...@esgyn.com|mailto:suresh.subb...@esgyn.com]>; Anoop Sharma 
<[anoop.sha...@esgyn.com|mailto:anoop.sha...@esgyn.com]>
Subject: RE: update path may need some work?
 
I have seen queue sizing issues on couple of places.
cqd GEN_DP2I_SIZE_DOWN '1024';
cqd UPD_ORDERED 'OFF';
cqd HBASE_ROWSET_VSBB_SIZE '20480';
 
for an upsert using load-under performing clearly because auto sizing was not 
kickin-in (this is for my bottle of wine bet with Hans POC ).
 
and queue of a UNION ALL operator in my HotCold also failing to resize, had to 
hardcode it using CQD
 
cqd gen_un_size_up '2048';
cqd gen_un_size_down '2048';
 
 
So given the queueing mechanism is in a shared class inherited by many 
operator, it would not surprise me if a common issue affecting multiple 
operators? It would not surprise me that if people start looking at dispatch 
metrics, this would be a widespread problem,
\|

> UNION ALL up and down queue size default value too small, or not dynamically 
> adjusted
> -------------------------------------------------------------------------------------
>
>                 Key: TRAFODION-3192
>                 URL: https://issues.apache.org/jira/browse/TRAFODION-3192
>             Project: Apache Trafodion
>          Issue Type: Bug
>          Components: sql-exe
>    Affects Versions: any
>            Reporter: Sandhya Sundaresan
>            Assignee: Sandhya Sundaresan
>            Priority: Major
>             Fix For: 2.4
>
>
> The union up queue size is hardcoded in nadefaults.cpp as a start value as 16 
> which
> is very low if large number of rows are being returned. Scan operator has it 
> set to 2048.
> Some operators further adjust this up size from the original value based on 
> estimate of
> the number of rows being returned. We can do that for union codegen method and
> also change the original up queue size to 2048.
>  
> Noticed that Transpose, Sequence also have the same issue and dynamic queue 
> resizing is missing. 



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