[HIVE-24389] Trailing zeros of constant decimal numbers are removed

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Component/s: Types
• Labels: pull-request-available
• Assignee: Krisztian Kasa
• Reporter: Krisztian Kasa
• Created: 16/Nov/20 12:55
• Updated: 30/Nov/20 14:47
• Resolved: 26/Nov/20 14:59

Description

In some case Hive removes trailing zeros of constant decimal numbers

select cast(1.1 as decimal(22, 2)) 
1.1

In this case WritableConstantHiveDecimalObjectInspector is used and this object inspector takes it's wrapped HiveDecimal scale instead of the scale specified in the wrapped typeinfo:

this = {WritableConstantHiveDecimalObjectInspector@14415} 
 value = {HiveDecimalWritable@14426} "1.1"
 typeInfo = {DecimalTypeInfo@14421} "decimal(22,2)"

However in case of an expression with an aggregate function WritableHiveDecimalObjectInspector is used

select cast(sum(1.1) as decimal(22, 2))
1.10

o = {HiveDecimalWritable@16633} "1.1"
oi = {WritableHiveDecimalObjectInspector@16634} 
 typeInfo = {DecimalTypeInfo@16640} "decimal(22,2)"

Casting the expressions to string

select cast(cast(1.1 as decimal(22, 2)) as string), cast(cast(sum(1.1) as decimal(22, 2)) as string)
1.1	1.10

Issue Links

• is related to: HIVE-12063 Pad Decimal numbers with trailing zeros to the scale of the column
• relates to: HIVE-24446 Materialized View plan alters explicit cast type in query
• links to: GitHub Pull Request #1676