High fieldNorm values causing really odd results

[Jorge Luis Betancourt González]

Hi everyone:

>From the last couple of week I'm noting some really odd results in my Solr 
>server, searching for the root cause the one thing I can point out is a very 
>high value of the fieldNorm parameter in the score calculation, an snippet of 
>the debug info:

{
   "match":true,
   "value":4907799.5,
   "description":"fieldWeight in 5316, product of:",
   "details":[
      {
         "match":true,
         "value":2,
         "description":"tf(freq=4.0), with freq of:",
         "details":[
            {
               "match":true,
               "value":4,
               "description":"termFreq=4.0"
            }
         ]
      },
      {
         "match":true,
         "value":3.7443538,
         "description":"idf(docFreq=49449, maxDocs=769173)"
      },
      {
         "match":true,
         "value":655360,
         "description":"fieldNorm(doc=5316)"
      }
   ]
}


This match is in the "title" field, which has 119669 total terms (which isn't 
such big number) and the total document count in this index is also rather 
small: 613772. 

>From [1] the fieldNorm encapsulates several parameters in its calculation:
  - Field boost (not used by us)
  - lengthNorm (which I'm suspecting is the culprit) 

I'm thinking on using omitNorms, but first I would like to discover why is this 
happening.

Any help on this issue?

Regards,