ES keeps returning every document
<p>I recently inherited an ES instance and ensured I read an entire book on ES cover-to-cover before posting this, however I'm afraid I'm unable to get even simple examples to work.</p>

<p>I have an index on our staging environment which exhibits behavior where every document is returned no matter what - I have a similar index on our QA environment which works like I would expect it to. For example I am running the following query against <a href="http://staging:9200/people_alias/_search?explain" rel="nofollow noreferrer">http://staging:9200/people_alias/_search?explain</a>:</p>

<pre><code>{ "query" : 
   { "filtered" : 
       { "query" : { "match_all" : {} },
          "filter" : { "term" : { "_id" : "34414405382" } } } } }
</code></pre>

<p>What I noticed on this staging environment is the score of every document is 1 and it is returning EVERY document in my index no matter what value I specify ...using ?explain I see the following:</p>

<pre><code>_explanation: {
value: 1
description: ConstantScore(*:*), product of:
details: [
{
value: 1, description: boost
}, { value: 1, description: queryNorm } ] }
</code></pre>

<p>On my QA environment, which correctly returns only one record I observe for ?explain:</p>

<pre><code>_explanation: {
value: 1
description: ConstantScore(cache(_uid:person#34414405382)), product of:
details: [ {
value: 1,
description: boost
}, {
value: 1,
description: queryNorm
}
]
}
</code></pre>

<p>The mappings are almost identical on both indices - the only difference is I removed the manual field-level boost values on some fields as I read field-level boosting is not recommended in favor of query-time boosting, however this should not affect the behavior of filtering on the document ID (right?)</p>

<p>Is there any clue I can glean from the differences in the explain output or should I post the index mappings? Are there any server-level settings I should consider checking? It doesn't matter what query I use on Staging, I can use match queries and exact match lookups on other fields and Staging just keeps returning every result with Score 1.0</p>

<p>I feel like I'm doing something very glaringly and obviously wrong on my Staging environment. Could someone please explain the presence of ConstantScore, boost and queryNorm? I thought from looking at examples in other literature I would see things like term frequency etc.</p>

<p>EDIT: I am issuing the query from Elastic Search Head plugin</p>

<p><a href="https://i.stack.imgur.com/oZgD4.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/oZgD4.png" alt="enter image description here"></a></p>