Why this simple elastic search query returns nothing?
<p>I want to search my database for a URL. I have documents like this:</p>

<pre><code>    {
        "_index": "test",
        "_type": "medhelp",
        "_id": "AVgPTB_dMXsxewkUBUNN",
        "_score": 1,
        "_source": {
            "title": "Pump minimed 404sp, 506,507,508",
            "text": "",
            "abstract": "\n            I am looking to buy one of these pump for testing purpose. It need to be in working condition. Email me if you have one for sale ***@****\n        ",
            "answers": [],
            "source": "medhelp",
            "link": "/posts/Diabetes---Type-1/Pump-minimed-404sp--506-507-508/show/2431714"
        }
</code></pre>

<p>When I search for source like this, I can get my results:</p>

<pre><code>{
    "query": {
        "prefix": {
            "source": "medhelp"
        }
    }
}
</code></pre>

<p>but when I try to do the same for the "link" field with a URL, there is always nothing returned. What's wrong with this:</p>

<pre><code>{
    "query": {
        "prefix": {
            "link": "/posts/Diabetes---Type-1/Pump-minimed-404sp--506-507-508/show/2431714"
        }
    }
}
</code></pre>

<p>And this is the result of above query:</p>

<pre><code>{
    "took": 5,
    "timed_out": false,
    "_shards": {
        "total": 5,
        "successful": 5,
        "failed": 0
    },
    "hits": {
        "total": 0,
        "max_score": null,
        "hits": []
    }
}
</code></pre>