1. TestIndexWriterMergePolicy.testMergeOnCommit will fail if the last
commit (the one that should trigger the full merge) doesn't have any
pending changes (which could occur if the last indexing thread
commits at the end). We can fix that by adding one more document
before that commit.
2. The previous implementation was throwing IOException if the commit
thread gets interrupted while waiting for merges to complete. This
violates IndexWriter's documented behavior of throwing
ThreadInterruptedException.
* LUCENE-8962: Add ability to selectively merge on commit
This adds a new "findCommitMerges" method to MergePolicy, which can
specify merges to be executed before the
IndexWriter.prepareCommitInternal method returns.
If we have many index writer threads, they will flush their DWPT buffers
on commit, resulting in many small segments, which can be merged before
the commit returns.
* Add missing Javadoc
* Fix incorrect comment
* Refactoring and fix intermittent test failure
1. Made some changes to the callback to update toCommit, leveraging
SegmentInfos.applyMergeChanges.
2. I realized that we'll never end up with 0 registered merges, because
we throw an exception if we fail to register a merge.
3. Moved the IndexWriterEvents.beginMergeOnCommit notification to before
we call MergeScheduler.merge, since we may not be merging on another
thread.
4. There was an intermittent test failure due to randomness in the time
it takes for merges to complete. Before doing the final commit, we wait
for pending merges to finish. We may still end up abandoning the final
merge, but we can detect that and assert that either the merge was
abandoned (and we have > 1 segment) or we did merge down to 1 segment.
* Fix typo
* Fix/improve comments based on PR feedback
* More comment improvements from PR feedback
* Rename method and add new MergeTrigger
1. Renamed findCommitMerges -> findFullFlushMerges.
2. Added MergeTrigger.COMMIT, passed to findFullFlushMerges and to
MergeScheduler when merging on commit.
* Update renamed method name in strings and comments
This adds a test to `BaseIndexFileFormatTestCase` that the combination
of opening a reader and calling `checkIntegrity` on it reads all bytes
of all files (including index headers and footers). This would help
detect most cases when `checkIntegrity` is not implemented correctly.
QueryBuilder currently has special logic for graph phrase queries with no slop,
constructing a spanquery that attempts to follow all paths using a combination of
OR and NEAR queries. However, this type of query has known bugs(LUCENE-7398).
This commit removes this logic and just builds a disjunction of phrase queries, one
phrase per path.
