Use the minSeq check in more places and add a test

Set minSeq so we can tell if the health check fails for conflict versus
something else (a conflict can arise if the index was rolled back between
the update and the search, by the IndexManager LRU)

nouveau/src/main/java/org/apache/couchdb/nouveau/health/IndexHealthCheck.java

@@ -47,6 +47,7 @@ protected Result check() throws Exception {
 
  final SearchRequest searchRequest = new SearchRequest();
  searchRequest.setQuery("_id:foo");
+ searchRequest.setMinUpdateSeq(1);
 
  final SearchResults searchResults = indexResource.searchIndex(name, searchRequest);
  if (searchResults.getTotalHits() == 1) {

nouveau/src/test/java/org/apache/couchdb/nouveau/lucene9/Lucene9IndexTest.java

@@ -33,6 +33,7 @@
 import org.apache.couchdb.nouveau.api.SearchResults;
 import org.apache.couchdb.nouveau.api.StringField;
 import org.apache.couchdb.nouveau.core.Index;
+import org.apache.couchdb.nouveau.core.StaleIndexException;
 import org.apache.couchdb.nouveau.core.UpdatesOutOfOrderException;
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.index.IndexWriter;
@@ -80,6 +81,7 @@ public void testSearching(@TempDir Path path) throws IOException {
  index.update("doc" + i, request);
  }
  final SearchRequest request = new SearchRequest();
+ request.setMinUpdateSeq(count);
  request.setQuery("*:*");
  final SearchResults results = index.search(request);
  assertThat(results.getTotalHits()).isEqualTo(count);
@@ -99,6 +101,7 @@ public void testSort(@TempDir Path path) throws IOException {
  index.update("doc" + i, request);
  }
  final SearchRequest request = new SearchRequest();
+ request.setMinUpdateSeq(count);
  request.setQuery("*:*");
  request.setSort(List.of("foo"));
  final SearchResults results = index.search(request);
@@ -119,6 +122,7 @@ public void testCounts(@TempDir Path path) throws IOException {
  index.update("doc" + i, request);
  }
  final SearchRequest request = new SearchRequest();
+ request.setMinUpdateSeq(count);
  request.setQuery("*:*");
  request.setCounts(List.of("bar"));
  final SearchResults results = index.search(request);
@@ -139,6 +143,7 @@ public void testRanges(@TempDir Path path) throws IOException {
  index.update("doc" + i, request);
  }
  final SearchRequest request = new SearchRequest();
+ request.setMinUpdateSeq(count);
  request.setQuery("*:*");
  request.setRanges(Map.of(
  "bar",
@@ -175,6 +180,22 @@ public void testOutOfOrder(@TempDir Path path) throws IOException {
  }
  }
 
+ @Test
+ public void testMinSeq(@TempDir Path path) throws IOException {
+ Index index = setup(path);
+ try {
+ // Require min seq 1 on new, empty index should fail.
+ assertThrows(StaleIndexException.class, () -> {
+ final SearchRequest request = new SearchRequest();
+ request.setMinUpdateSeq(1);
+ request.setQuery("*:*");
+ index.search(request);
+ });
+ } finally {
+ cleanup(index);
+ }
+ }
+
  @Test
  public void testInfo(@TempDir Path path) throws IOException {
  Index index = setup(path);