Handling of nested fields / object type

[sandeshkr419]

Description

Resolves object type handling when nested fields are present in mappings.
Basically try to skip including the outer field in schema and not the nested flattened out fields.

Caused by: java.sql.SQLException: exception while executing query: Unable to convert the type ANY
        at org.apache.calcite.avatica.Helper.createException(Helper.java:56)
        at org.apache.calcite.avatica.Helper.createException(Helper.java:41)
        at org.apache.calcite.avatica.AvaticaConnection.executeQueryInternal(AvaticaConnection.java:579)
        at org.apache.calcite.avatica.AvaticaPreparedStatement.executeQuery(AvaticaPreparedStatement.java:137)
        at org.opensearch.sql.opensearch.executor.OpenSearchExecutionEngine.lambda$execute$6(OpenSearchExecutionEngine.java:213)
        ... 17 more

• Tested queries on the flattened nested objects
• Tested queries on other field types which were returning errors previously.
• Tested group-by as well on flattened objects

curl "localhost:9200/test-grab-index/_mappings?pretty"

{
  "test-grab-index" : {
    "mappings" : {
      "dynamic" : "false",
      "properties" : {
        "@timestamp" : {
          "type" : "date"
        },
        "additional_data" : {
          "type" : "text",
          "analyzer" : "standard"
        },
        "app_name" : {
          "type" : "keyword"
        },
        "auth" : {
          "properties" : {
            "metadata" : {
              "properties" : {
                "instance_id" : {
                  "type" : "keyword"
                },
                "role" : {
                  "type" : "keyword"
                }
              }
            }
          }
        },
        "availability_zone" : {
          "type" : "keyword"
        },
        "class" : {
          "type" : "keyword"
        },
        "common_booking_code" : {
          "type" : "keyword"
        },
        "common_client" : {
          "type" : "keyword"
        },
        "common_client_ip" : {
          "type" : "keyword"
        },
        "common_driver_id" : {
          "type" : "long"
        },
        "common_endpoint" : {
          "type" : "keyword"
        },
        "common_endpoint_elapsed" : {
          "type" : "long"
        },
        "common_error" : {
          "type" : "text",
          "analyzer" : "standard"
        },
        "common_error_type" : {
          "type" : "keyword"
        },
        "common_eta" : {
          "type" : "text",
          "analyzer" : "standard"
        },
        "common_http_url" : {
          "type" : "keyword"
        },
        "common_merchant_id" : {
          "type" : "keyword"
        },
        "common_order_id" : {
          "type" : "keyword"
        },
        "common_passenger_id" : {
          "type" : "long"
        },
        "common_provider" : {
          "type" : "keyword"
        },
        "common_reference" : {
          "type" : "keyword"
        },
        "common_region" : {
          "type" : "keyword"
        },
        "common_request" : {
          "type" : "text",
          "analyzer" : "standard"
        },
        "common_request_id" : {
          "type" : "keyword"
        },
        "common_response" : {
          "type" : "text",
          "analyzer" : "standard"
        },
        "common_service" : {
          "type" : "keyword"
        },
        "common_trace_id" : {
          "type" : "keyword"
        },
        "common_user" : {
          "type" : "keyword"
        },
        "common_vehicle_type" : {
          "type" : "long"
        },
        "event_type" : {
          "type" : "keyword"
        },
        "gopoi_accuracy" : {
          "type" : "double"
        },
        "gopoi_keyword" : {
          "type" : "keyword"
        },
        "gopoi_type" : {
          "type" : "keyword"
        },
        "gopoi_xcountry" : {
          "type" : "keyword"
        },
        "hostname" : {
          "type" : "keyword"
        },
        "invalid_data" : {
          "type" : "text",
          "analyzer" : "standard"
        },
        "jaya_rental_agreement_id" : {
          "type" : "long"
        },
        "jaya_user" : {
          "type" : "keyword"
        },
        "log_level" : {
          "type" : "keyword"
        },
        "log_write_epoch" : {
          "type" : "long"
        },
        "message" : {
          "type" : "text",
          "analyzer" : "custom_message_analyzer"
        },
        "orbital_location_id" : {
          "type" : "long"
        },
        "pipeline_error" : {
          "type" : "text",
          "index" : false
        },
        "request" : {
          "properties" : {
            "headers" : {
              "properties" : {
                "x-forwarded-for" : {
                  "type" : "keyword"
                }
              }
            },
            "operation" : {
              "type" : "keyword"
            },
            "path" : {
              "type" : "keyword"
            }
          }
        },
        "source" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        },
        "stacktrace" : {
          "type" : "text",
          "analyzer" : "standard"
        },
        "tags" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        },
        "ucm_config_key" : {
          "type" : "keyword"
        },
        "ucm_operation" : {
          "type" : "keyword"
        },
        "ucm_repository" : {
          "type" : "keyword"
        },
        "ucm_running_env" : {
          "type" : "keyword"
        },
        "vpc_name" : {
          "type" : "keyword"
        }
      }
    }
  }
}

 curl -X POST "http://localhost:9200/_plugins/_ppl" \
  -H "Content-Type: application/json" \
  -d '{
    "query": "source=test-grab-index | stats dc(auth.metadata.instance_id) as min"
  }'
{
  "schema": [
    {
      "name": "min",
      "type": "bigint"
    }
  ],
  "datarows": [
    [
      6
    ]
  ],
  "total": 1,
  "size": 1
}

curl -X POST "http://localhost:9200/_plugins/_ppl" \
  -H "Content-Type: application/json" \
  -d '{
    "query": "source=test-grab-index | stats min(common_passenger_id) as min"
  }'
{
  "schema": [
    {
      "name": "min",
      "type": "bigint"
    }
  ],
  "datarows": [
    [
      1001
    ]
  ],
  "total": 1,
  "size": 1
}

curl -X POST "http://localhost:9200/_plugins/_ppl" \
  -H "Content-Type: application/json" \
  -d '{
    "query": "source=test-grab-index | stats min(common_passenger_id) by auth.metadata.instance_id"
  }'
{
  "schema": [
    {
      "name": "min(common_passenger_id)",
      "type": "bigint"
    },
    {
      "name": "auth.metadata.instance_id",
      "type": "string"
    }
  ],
  "datarows": [
    [
      1001,
      "i-001"
    ],
    [
      1002,
      "i-002"
    ],
    [
      1003,
      "i-003"
    ],
    [
      1004,
      "i-004"
    ],
    [
      1005,
      "i-005"
    ],
    [
      1006,
      "i-006"
    ]
  ],
  "total": 6,
  "size": 6
}

Check List

• New functionality includes testing.
• New functionality has been documented.
• New functionality has javadoc added.
• New functionality has a user manual doc added.
• New PPL command checklist all confirmed.
• API changes companion pull request created.
• Commits are signed per the DCO using --signoff or -s.
• Public documentation issue/PR created.

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