[IMPALA-13138] Never smallify existing StringValue objects, only new ones during DeepCopy

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: Impala 4.4.0
• Fix Version/s: Impala 4.5.0, Impala 4.4.1
• Target Version: Impala 4.4.1
• Epic Color: ghx-label-1
• Assignee: Zoltán Borók-Nagy
• Reporter: Zoltán Borók-Nagy
• Created: 06/Jun/24 17:44
• Updated: 14/Aug/24 00:47
• Resolved: 17/Jun/24 11:25

Description

Currently we have the following problematic line:

https://github.com/apache/impala/blob/880690c7bd46e6af058d8a669bea41af4a131049/be/src/runtime/buffered-tuple-stream.cc#L968

It modifies the string value of an existing tuple and it can corrupt the BufferedTupleStream.

We should only smallify string values during deepcopy, and only the target string value, never the source.

Issue Links

• is caused by: IMPALA-12373 Implement Small String Optimization for StringValue