[IMPALA-5629] list::size() in BufferedTupleStreamV2::AdvanceWritePage() is expensive

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Impala 2.10.0
• Fix Version/s: Impala 2.10.0
• Component/s: Backend
• Labels: perf
• Target Version: Impala 2.10.0
• Epic Color: ghx-label-4
• Assignee: Tim Armstrong
• Reporter: Tim Armstrong
• Created: 07/Jul/17 22:31
• Updated: 11/Jul/17 03:23
• Resolved: 11/Jul/17 03:23

Description

In a test run executing a very large join I saw a lot of CPU being burnt in BufferedTupleStreamV2::AdvanceWritePage()

It looks like it's all being spent iterating over the pages_ linked list. list::size() is an O operation in some implementations.