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From Shawn Heisey <>
Subject Re: SolrJ cannot get actual cause of error
Date Sun, 30 Sep 2018 13:34:45 GMT
On 9/29/2018 3:08 AM, Ryan Qin wrote:
> I’m working on a project which uses solr as search engine. I found I 
> cannot get the root cause of error from SolrJ.

CloudSolrClient uses LBHttpSolrClient internally.  This client has a 
tendency to wrap all exceptions in the "No live SolrServers" message.  
There is an existing issue for that problem:

That issue is three years old, and sorta fizzled out without really 
going anywhere.  There hasn't been any activity in Jira for nearly two 

> The root cause is wrapped very deep, like:

The image that you attached did not make it to the list. We can't see 
it.  Apache mailing lists remove most attachments.  Using a paste 
website or a file sharing site is the best option for sharing content.

Even if SOLR-7951 is fixed, root causes will still often be deeply 
nested in exceptions, and the level of nesting varies widely.  Because 
the innermost exception in the nesting may not actually say anything 
useful about the root cause, trying to determine a root cause 
programmatically is very difficult.  It usually takes review by a 
person, looking at ALL of the "Caused by" messages closely.  Often the 
problem may only make sense to someone who's actually familiar with the 
code, and the exact version of Solr is required to decipher them.  The 
goal is to have error messages that ANYONE can understand ... but 
reaching that goal can be very difficult.


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