[IMPALA-6616] UUIDs for query id's never seem to start with 0

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Not A Bug
• Component/s: Backend
• Epic Color: ghx-label-8
• Assignee: Unassigned
• Reporter: Philip Martin
• Created: 07/Mar/18 00:20
• Updated: 21/Dec/20 19:27
• Resolved: 21/Dec/20 19:27

Description

In working with a bucket of Impala profiles, I was surprised to find that I had no queries whose ID began with "0". I would have expected the id space to be uniformly distributed.

Here's a simple reproduction where I run 200 queries and find that none of them had a query id that began with 0.

$(for i in $(seq 20); do impala-shell.sh --query 'select 1;select 2;select 3;select 4;select 5;select 6;select 7; select 8; select 9;select 10;' |& grep -o 'query_id=.*' | awk -F= '{ print $2 }' | cut -c 1; done) | sort | uniq -c
     12 1
      8 2
     14 3
     10 4
     17 5
     17 6
     12 7
     13 8
     12 9
      7 a
     14 b
     18 c
     11 d
     20 e
     15 f