The field has incompatible sort types: [FLOAT] and [DOUBLE] across shards!

[eliasbui]

Elasticsearch .NET Client Issue Report

Elastic.Clients.Elasticsearch version: 8.17.1
Elasticsearch version: 8.15.3
.NET runtime version: 9.0
Operating system version: Windows

Description of the problem

When sorting by a numeric field that has inconsistent data types across shards (FLOAT vs DOUBLE), the query executes successfully when run directly in Elasticsearch console but fails when executed through the .NET client with the error:

the field has incompatible sort types: [FLOAT] and [DOUBLE] across shards!

The same query, same data, same mapping, but executed through different interfaces produce different behaviors.

Steps to reproduce

1. Create an index with a numeric field that has mixed FLOAT/DOUBLE types across shards
2. Execute a search query with sorting on the numeric field using the .NET client:

var searchResult = await elasticClient.SearchAsync<HouseHoldRecord>(c =>
{
    c.Query(BuildSearch(options));
    c.Sort(s => s.Field(f => f.LastReportedRevenue!, new FieldSort { Order = SortOrder.Desc }));
    c.Size(options.PageSize);
    c.From((options.PageIndex - 1) * options.PageSize);
    c.TrackTotalHits(new TrackHits(true));
});

3. The query fails with shard incompatibility error

Expected behavior

The query should work consistently between direct Elasticsearch console execution and .NET client execution, or provide better handling of mixed numeric types across shards.

Console Query (Works)

POST /my-index/_search
{
  "from": 0,
  "query": {
    "bool": {
      "boost": 2,
      "must": {
        "match": {
          "taxCode.keyword": {
            "query": "1234567890"
          }
        }
      },
      "_name": "SearchRecord"
    }
  },
  "size": 30,
  "sort": {
    "lastReportedRevenue": {
      "order": "desc"
    }
  },
  "track_total_hits": true
}

.NET Client Query (Fails)

var searchRequest = new SearchRequestDescriptor<MyRecord>()
    .Query(q => q.Term(t => t.Field("taxCode.keyword").Value("1234567890")))
    .Sort(s => s.Field("lastReportedRevenue", new FieldSort { Order = SortOrder.Desc }))
    .Size(30)
    .TrackTotalHits(new TrackHits(true));

var response = await elasticClient.SearchAsync(searchRequest);

Connection Settings

var settings = new ElasticsearchClientSettings(new Uri("https://localhost:9200"))
    .DefaultIndex("my-index");
var elasticClient = new ElasticsearchClient(settings);

Workaround Found

Using script-based sorting resolves the issue:

c.Sort(s => s.Script(new ScriptSort
{
    Script = new InlineScript("Math.round(doc['lastReportedRevenue'].value * 100) / 100.0")
    {
        Lang = "painless"
    },
    Type = "number",
    Order = SortOrder.Desc
}));

Alternative Solutions Attempted

1. Using UnmappedType:

c.Sort(s => s.Field("lastReportedRevenue", new FieldSort 
{ 
    Order = SortOrder.Desc,
    UnmappedType = "double"
}));

2. Using Expression Script:

c.Sort(s => s.Script(new ScriptSort
{
    Script = new InlineScript("doc['lastReportedRevenue'].value")
    {
        Lang = "expression"
    },
    Type = "number",
    Order = SortOrder.Desc
}));

Additional Context

• This issue appears to be related to how the .NET client handles field sorting when there are type inconsistencies across shards
• Direct Elasticsearch queries handle this scenario more gracefully
• The issue may be version-specific as different Elasticsearch versions (8.15.1 vs 8.16.1) show different behaviors
• Script-based sorting works as a workaround but impacts performance

Debug Information

Error occurs during query execution, not during client initialization. The field mapping shows mixed types across different shards which causes the sorting conflict in the .NET client but not in direct console queries.

Environment Details

• Framework: .NET 9.0
• Client: Elastic.Clients.Elasticsearch 8.17.1
• Server: Elasticsearch 8.15.3
• OS: Windows
• Deployment: Multi-shard setup with type inconsistencies

[flobernd]

Hi @eliasbui ,

The "search" operation searches all indices by default.

In the Kibana dev console you included "my-index" in the url, but in the .NET application you don't specify the index directly.

I see that your confusion probably is caused by the fact that you set a default index.

Currently, the default index is not used for operations that accept multiple indices. See as well #8215.

We might change that behavior in the future.

[eliasbui]

@flobernd sorry i don't have leak secret, so i use default value. ^^

[flobernd]

What I was trying to say is that the default index does not apply for "search".

Could you please try to set it explicitly:

var searchRequest = new SearchRequestDescriptor<MyRecord>()
    .Index("my-index") // <- limit indices to just "my-index"
    .Query(q => q.Term(t => t.Field("taxCode.keyword").Value("1234567890")))
    .Sort(s => s.Field("lastReportedRevenue", new FieldSort { Order = SortOrder.Desc }))
    .Size(30)
    .TrackTotalHits(new TrackHits(true));

var response = await elasticClient.SearchAsync(searchRequest);