Elastic Low Level Client - How to include multiple indexes in a search query

Question

I'm struggling to figure out how to include multiple indexes in a search using the Elastic low level client.

My understanding (right or wrong) is that I should be able to include multiple indexes by separation of commas, this doesn't work for me though. In the code example below, I find that the first index specified is still working and returning results, but the second one is ignored. Any ideas?

Appsettings.json file:

    // System settings configured here for the WebApp. Applicable to all users.
  "SystemSettings": {
    // Sets the maximum number of distinct values returned by Elastic for a log property
    "_distinctPropertyValuesLimit": 1000, // See LogPropertiesController.cs
    // String for the list of Elastic Search indexes that are searched by default.
    "indexesToSearch": "webapp-razor-*, systemconfig-api-*"
  }

Query class:

_indexesToSearch = configuration.GetSection("SystemSettings").GetSection("indexesToSearch").Value;

var searchResponse = await _elasticLowLevelClient.SearchAsync<StringResponse>(_indexesToSearch, @"
                {
                    ""from"": """ + fromParameter + @""",
                    ""size"": """ + rowsPerPage + @""",
                    ""query"": {
                        ""match"": {
                            """ + searchColumn + @""": {
                                ""query"": """ + searchString + @"""
                            }
                        }
                    },
                    ""sort"": [
                          {
                            ""@timestamp"": {
                            ""order"": ""desc""
                            }
                          }
                       ]
                    }
                ");

Answer 1

Turns out that there must not be any spaces between the index names when multiple values are provided, see below: