1

I configured Single node Presto cluster and able to create tables from the data in my custom s3 service. However when I try to query data like select * from test limit 10; the result I am getting here is like this - 

 time | quality |  o3
------+---------+------
 NULL | NULL    | NULL
 NULL | NULL    | NULL
 NULL | NULL    | NULL
 NULL | NULL    | NULL
 NULL | NULL    | NULL
 NULL | NULL    | NULL
 NULL | NULL    | NULL
 NULL | NULL    | NULL
 NULL | NULL    | NULL
 NULL | NULL    | NULL

My hive-metastore is also stable and working fine. But I an not able to understand why I am getting data as NULL. However, when I query data for SELECT COUNT(*) FROM test, I get result like 25; rows. This means the table has data in it. How should I resolve this issue?

I am very new to presto. Need help!

a13e
  • 838
  • 2
  • 11
  • 27
  • 1
    What version of Presto are you running? What file format are you using for your tables? How did you create the tables and insert the data? – Martin Traverso Jun 19 '20 at 05:28
  • @MartinTraverso I am using presto 0.330. Parquet is the format I have my data in the s3 buckets. I created the table on hive metastore that presto uses. Data is available in the S3 buckets. – a13e Jun 19 '20 at 07:05
  • @MartinTraverso I am using CTAS statement as follows - CREATE TABLE IF NOT EXISTS test_table_3 ( time TIMESTAMP, quality VARCHAR, pm10 REAL) WITH (format = 'parquet', external_location = 's3a://air-detection/pm10/'); – a13e Jun 19 '20 at 20:13
  • Ever figure this one out? I'm running into something similar now (with some "struct" fields of a "stored as orc" Hive table), so I'm curious. :-) – Thogek May 27 '21 at 23:51

0 Answers0