[GitHub] [incubator-iotdb] jixuan1989 commented on pull request #1367: [IOTDB-749] Handle select * from root OOM

[GitBox <gi...@apache.org>]

jixuan1989 commented on pull request #1367:
URL: https://github.com/apache/incubator-iotdb/pull/1367#issuecomment-651013673


   I register 10_000_000 timeseries by:
   ```java
     public static void main(String[] args) throws ClassNotFoundException, SQLException {
       Class.forName("org.apache.iotdb.jdbc.IoTDBDriver");
       try (Connection connection = DriverManager
           .getConnection("jdbc:iotdb://127.0.0.1:6667/", "root", "root");
           Statement statement = connection.createStatement()) {
         int total = 10_000_000;
         try {
           statement.execute("SET STORAGE GROUP TO root.sg1");
           for (int i = 0; i < total; i++) {
             statement.execute(
                 "CREATE TIMESERIES root.sg1.d1.s" + i
                     + " WITH DATATYPE=INT64, ENCODING=RLE, COMPRESSOR=SNAPPY");
             if (i % 10_000 == 0) {
               System.out.println((double) i / total * 100 + "%");
             }
           }
         } catch (IoTDBSQLException e) {
           System.out.println(e.getMessage());
         }
         
       } catch (IoTDBSQLException e) {
         System.out.println(e.getMessage());
       }
     }
   ```
   
   And then call `select * from root`;
   The CLI hangs..
   
   


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