[jira] [Created] (DRILL-798) explicit casting a string to float loses precision

["Chun Chang (JIRA)" <ji...@apache.org>]

Chun Chang created DRILL-798:
--------------------------------

             Summary: explicit casting a string to float loses precision
                 Key: DRILL-798
                 URL: https://issues.apache.org/jira/browse/DRILL-798
             Project: Apache Drill
          Issue Type: Bug
            Reporter: Chun Chang
            Assignee: Jinfeng Ni


This is tested on git.commit.id.abbrev=5d7e3d3

Consider the following query which cast a string '999999999' into float. This yielded 1.0e9 with drill which doesn't look right.

0: jdbc:drill:schema=dfs> select cast('999999999' as float) from data limit 1;
+------------+
|   EXPR$0   |
+------------+
| 1.0E9      |
+------------+

0: jdbc:drill:schema=dfs> explain plan for select cast('999999999' as float) from data limit 1;
+------------+------------+
|    text    |    json    |
+------------+------------+
| ScreenPrel
  SelectionVectorRemoverPrel
    LimitPrel(fetch=[1])
      ProjectPrel(EXPR$0=[CAST('999999999'):FLOAT NOT NULL])
        ScanPrel(groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath [path=maprfs:/user/root/mondrian/data]], selectionRoot=/user/root/mondrian/data, columns=null]])
 | {
  "head" : {
    "version" : 1,
    "generator" : {
      "type" : "ExplainHandler",
      "info" : ""
    },
    "type" : "APACHE_DRILL_PHYSICAL",
    "options" : [ ],
    "resultMode" : "EXEC"
  },
  "graph" : [ {
    "pop" : "parquet-scan",
    "@id" : 1,
    "entries" : [ {
      "path" : "maprfs:/user/root/mondrian/data"
    } ],
    "storage" : {
      "type" : "file",
      "connection" : "maprfs:///",
      "workspaces" : {
        "default" : {
          "location" : "/user/root/mondrian/",
          "writable" : false,
          "storageformat" : null
        },
        "home" : {
          "location" : "/",
          "writable" : false,
          "storageformat" : null
        },
        "root" : {
          "location" : "/",
          "writable" : false,
          "storageformat" : null
        },
        "tmp" : {
          "location" : "/tmp",
          "writable" : true,
          "storageformat" : "csv"
        }
      },
      "formats" : {
        "psv" : {
          "type" : "text",
          "extensions" : [ "tbl" ],
          "delimiter" : "|"
        },
        "csv" : {
          "type" : "text",
          "extensions" : [ "csv" ],
          "delimiter" : ","
        },
        "tsv" : {
          "type" : "text",
          "extensions" : [ "tsv" ],
          "delimiter" : "\t"
        },
        "parquet" : {
          "type" : "parquet"
        },
        "json" : {
          "type" : "json"
        }
      }
    },
    "format" : {
      "type" : "parquet"
    },
    "selectionRoot" : "/user/root/mondrian/data"
  }, {
    "pop" : "project",
    "@id" : 2,
    "exprs" : [ {
      "ref" : "`EXPR$0`",
      "expr" : "cast( ('999999999' ) as FLOAT4 )"
    } ],
    "child" : 1,
    "initialAllocation" : 1000000,
    "maxAllocation" : 10000000000
  }, {
    "pop" : "limit",
    "@id" : 3,
    "child" : 2,
    "first" : 0,
    "last" : 1,
    "initialAllocation" : 1000000,
    "maxAllocation" : 10000000000
  }, {
    "pop" : "selection-vector-remover",
    "@id" : 4,
    "child" : 3,
    "initialAllocation" : 1000000,
    "maxAllocation" : 10000000000
  }, {
    "pop" : "screen",
    "@id" : 5,
    "child" : 4,
    "initialAllocation" : 1000000,
    "maxAllocation" : 10000000000
  } ]
} |



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