[IMPALA-4773] Supportability improvements for IMPALA-4765

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: Impala 2.8.0
• Component/s: Catalog
• Labels: observability supportability
• Target Version: Product Backlog
• Assignee: Unassigned
• Reporter: Alexander Behm
• Created: 16/Jan/17 18:05
• Updated: 21/Jan/20 21:03

Description

The patch for addressing IMPALA-4765 introduced a new critical data structure 'tableLoadingBarrier_' to prevent using multiple table-loading threads for the same table.

However, the following bug might be difficult to detect with the current logging//metrics. If for some reason an entry in the 'tableLoadingBarrier_' is never removed then that table will never again be loaded and all queries waiting for that table will hang (and will not be cancellable, see IMPALA-915). The only remedy is to restart the catalogd.

We should carefully consider the above possibility and how to debug/identify it from logs, and perhaps enhance the logging.