Issue Summary

An out-of-order timestamp (OOO ts) assertion failure was encountered in a MongoDB patch build using today's drop and some unrelated prefetch changes. The failure occurred in the WiredTiger history store (hs) code during a checkpoint operation, with the following error:

WiredTiger assertion failed: 'ts == 1 || ts == 0'. out-of-order timestamp update detected, found an existing update with hs_start_ts=(1770953528, 160), time_window=start: (1770953528, 160)/(1770953528, 160)/(0, 0)/0/342 | stop: (1770953528, 205)/(1770953528, 205)/(0, 0)/0/390, that exists later than specified ts=(1770953528, 179)

Context

• The failure was observed in the test js_test:lookup_mongod_unaware on an ASC patch build.
• The patch includes the latest drop and unrelated prefetch changes.
• The error is in the WiredTiger history store code, specifically in the checkpoint thread.
• Given the size of the drop, it is difficult to isolate the exact change responsible.
• It is suspected this issue may also occur in CI runs for the drop.

Proposed Solution

• Investigate the out-of-order timestamp assertion failure in the WiredTiger history store code.
• Attempt to reproduce the failure in CI with the current drop.
• Isolate any recent changes that could have impacted timestamp handling in the history store.
• Link this ticket to the failure and related discussions.