{
    head:{
        type:"APACHE_DRILL_PHYSICAL",
        version:"1",
        generator:{
            type:"manual"
        }
    },
    graph:[
        {
            @id:1,
            pop:"mock-sub-scan",
            url: "http://apache.org",
            entries:[
                {records: 5, types: [
                  {name: "float4col", type: "FLOAT4", mode: "REQUIRED"},
                  {name: "float8col", type: "FLOAT8", mode: "REQUIRED"} ,
                  {name: "intcol", type: "INT", mode: "REQUIRED"} ,
                  {name: "bigintcol", type: "BIGINT", mode: "REQUIRED"}
             ]}
            ]
        },
        {
            @id:2,
            child: 1,
            pop:"project",
            exprs: [
                { ref: "varchar_cast", expr:"cast('abc' as int)" }
            ]
        },
        {
            @id: 3,
            child: 2,
            pop: "screen"
        }
    ]
}