Strange Behaviour in Elasticsearch Aggregation Query

Elastic Stack Elasticsearch
1

Hi,

I saw strange behavior in Es Aggregation query.
Sample Query:
curl -XGET "http://localhost:9200/i*/cdr/_search?pretty" -d '
{
"size": 0,
"aggs": {
"Diagnosticcode": {
"filter": {
"range": {
"@timestamp": {
"gte": "2014-07-28T00:56:48.363-05:00",
"lte": "2014-07-28T00:57:18.391-05:00"
}
}
},
"aggs": {
"DiagAgg": {
"terms": {
"field": "Diag"
}
}
}
}
}
}
I am running this Aggregation query every 30 seconds so whatever document comes it sends to Graphite.
But i saw strange behavior like hits are coming properly but document some time it is coming properly but some time it is not coming properly.

Please suggest.

Thanks,
Sumit Gupta