[LUCENE-3348] IndexWriter applies wrong deletes during concurrent flush-all

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.0-ALPHA
• Component/s: core/index
• Lucene Fields: New, Patch Available
• Assignee: Simon Willnauer
• Reporter: Michael McCandless
• Created: 28/Jul/11 17:16
• Updated: 28/Aug/22 12:54
• Resolved: 10/Aug/11 07:37

Description

Yonik uncovered this with the TestRealTimeGet test: if a flush-all is
underway, it is possible for an incoming update to pick a DWPT that is
stale, ie, not yet pulled/marked for flushing, yet the DW has cutover
to a new deletes queue. If this happens, and the deleted term was
also updated in one of the non-stale DWPTs, then the wrong document is
deleted and the test fails by detecting the wrong value.

There's a 2nd failure mode that I haven't figured out yet, whereby 2
docs are returned when searching by id (there should only ever be 1
doc since the test uses updateDocument which is atomic wrt
commit/reopen).

Yonik verified the test passes pre-DWPT, so my guess is (but I
have yet to verify) this test also passes on 3.x. I'll backport
the test to 3.x to be sure.