Unexpected query result

[Igor Kuzmenko <f1...@gmail.com>]

Runnuning simple '*select count(*) from test_table*'  query returned me
500_000 result.
But when i run '*select count(distinct field) from test_table*' query
result is 500_001.

How it coud happen, that in table with 500_000 records have 500_001 unique
field values?

I'm using Hive from HDP 2.5.0 platform.
Table stored as ORC.

RE: Unexpected query result

[Frank Luo <jl...@merkleinc.com>]

One possibility is that count(*) gives a cached stat, while count(distinct field) actually read data and perform the logic.

Try to set the below and test again:

set hive.compute.query.using.stats=false;



From: Igor Kuzmenko [mailto:f1sherox@gmail.com]
Sent: Monday, August 21, 2017 10:01 AM
To: user@hive.apache.org
Subject: Unexpected query result

Runnuning simple 'select count(*) from test_table'  query returned me 500_000 result.
But when i run 'select count(distinct field) from test_table' query result is 500_001.

How it coud happen, that in table with 500_000 records have 500_001 unique field values?

I'm using Hive from HDP 2.5.0 platform.
Table stored as ORC.

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