如何将hive查询转换为抽象语法树？

Question

任何人都可以告诉我如何将蜂房查询转换为抽象语法树？ 例如：select * from cust where其中cust_num = 100; 我如何将它转换成AST？以及如何将此AST转换为QB树？请帮忙。提前致谢。

Answer 1

您可以使用EXPLAIN命令与EXTENDED。假设我有一个名为demo表一列n1，然后发出说明会给我这样的：

hive> EXPLAIN EXTENDED select * from demo where n1='aaa'; 
OK 
ABSTRACT SYNTAX TREE: 
    (TOK_QUERY (TOK_FROM (TOK_TABREF (TOK_TABNAME demo))) (TOK_INSERT (TOK_DESTINATION (TOK_DIR TOK_TMP_FILE)) (TOK_SELECT (TOK_SELEXPR TOK_ALLCOLREF)) (TOK_WHERE (= (TOK_TABLE_OR_COL n1) 'aaa')))) 

STAGE DEPENDENCIES: 
    Stage-1 is a root stage 
    Stage-0 is a root stage 

STAGE PLANS: 
    Stage: Stage-1 
    Map Reduce 
     Alias -> Map Operator Tree: 
     demo 
      TableScan 
      alias: demo 
      GatherStats: false 
      Filter Operator 
       isSamplingPred: false 
       predicate: 
        expr: (n1 = 'aaa') 
        type: boolean 
       Select Operator 
       expressions: 
         expr: n1 
         type: string 
         expr: n2 
         type: string 
       outputColumnNames: _col0, _col1 
       File Output Operator 
        compressed: false 
        GlobalTableId: 0 
        directory: hdfs://localhost:9000/tmp/hive-apache/hive_2013-06-13_19-55-21_578_6086176948010779575/-ext-10001 
        NumFilesPerFileSink: 1 
        Stats Publishing Key Prefix: hdfs://localhost:9000/tmp/hive-apache/hive_2013-06-13_19-55-21_578_6086176948010779575/-ext-10001/ 
        table: 
         input format: org.apache.hadoop.mapred.TextInputFormat 
         output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat 
         properties: 
         columns _col0,_col1 
         columns.types string:string 
         escape.delim \ 
         serialization.format 1 
        TotalFiles: 1 
        GatherStats: false 
        MultiFileSpray: false 
     Needs Tagging: false 
     Path -> Alias: 
     hdfs://localhost:9000/user/hive/warehouse/demo [demo] 
     Path -> Partition: 
     hdfs://localhost:9000/user/hive/warehouse/demo 
      Partition 
      base file name: demo 
      input format: org.apache.hadoop.mapred.TextInputFormat 
      output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat 
      properties: 
       bucket_count -1 
       columns n1,n2 
       columns.types string:string 
       field.delim , 
       file.inputformat org.apache.hadoop.mapred.TextInputFormat 
       file.outputformat org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat 
       location hdfs://localhost:9000/user/hive/warehouse/demo 
       name default.demo 
       serialization.ddl struct demo { string n1, string n2} 
       serialization.format , 
       serialization.lib org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe 
       transient_lastDdlTime 1370932655 
      serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe 

       input format: org.apache.hadoop.mapred.TextInputFormat 
       output format: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat 
       properties: 
       bucket_count -1 
       columns n1,n2 
       columns.types string:string 
       field.delim , 
       file.inputformat org.apache.hadoop.mapred.TextInputFormat 
       file.outputformat org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat 
       location hdfs://localhost:9000/user/hive/warehouse/demo 
       name default.demo 
       serialization.ddl struct demo { string n1, string n2} 
       serialization.format , 
       serialization.lib org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe 
       transient_lastDdlTime 1370932655 
       serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe 
       name: default.demo 
      name: default.demo 

    Stage: Stage-0 
    Fetch Operator 
     limit: -1 


Time taken: 5.316 seconds