Log flush_stats and commit_stats in testMaybeFlush

This test failed a few times over the last several months. It seems that
we triggered a flush, but CI was too slow to finish it in several
seconds. I added the flush stats and commit stats and unmuted this test.
We should have a good clue if this test fails again.

Relates #37896

Author: dnhatn

server/src/test/java/org/elasticsearch/index/shard/IndexShardIT.java

@@ -40,6 +40,7 @@
 import org.elasticsearch.cluster.routing.UnassignedInfo;
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.CheckedRunnable;
+import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.UUIDs;
 import org.elasticsearch.common.breaker.CircuitBreaker;
 import org.elasticsearch.common.bytes.BytesArray;
@@ -57,12 +58,14 @@
 import org.elasticsearch.index.IndexService;
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.VersionType;
+import org.elasticsearch.index.engine.CommitStats;
 import org.elasticsearch.index.engine.Engine;
 import org.elasticsearch.index.engine.SegmentsStats;
 import org.elasticsearch.index.flush.FlushStats;
 import org.elasticsearch.index.mapper.SourceToParse;
 import org.elasticsearch.index.seqno.SequenceNumbers;
 import org.elasticsearch.index.translog.Translog;
+import org.elasticsearch.index.translog.TranslogStats;
 import org.elasticsearch.indices.IndicesService;
 import org.elasticsearch.indices.breaker.CircuitBreakerService;
 import org.elasticsearch.indices.breaker.CircuitBreakerStats;
@@ -337,7 +340,6 @@ public void testIndexCanChangeCustomDataPath() throws Exception {
         assertPathHasBeenCleared(endDir.toAbsolutePath());
     }
 
-    @AwaitsFix(bugUrl = "https://github.com/elastic/elasticsearch/issues/37896")
     public void testMaybeFlush() throws Exception {
         createIndex("test", Settings.builder().put(IndexSettings.INDEX_TRANSLOG_DURABILITY_SETTING.getKey(), Translog.Durability.REQUEST)
             .build());
@@ -376,8 +378,12 @@ public void testMaybeFlush() throws Exception {
         logger.info("--> translog size after delete: [{}] num_ops [{}] generation [{}]",
             translog.stats().getUncommittedSizeInBytes(), translog.stats().getUncommittedOperations(), translog.getGeneration());
         assertBusy(() -> { // this is async
-            logger.info("--> translog size on iter  : [{}] num_ops [{}] generation [{}]",
-                translog.stats().getUncommittedSizeInBytes(), translog.stats().getUncommittedOperations(), translog.getGeneration());
+            final TranslogStats translogStats = translog.stats();
+            final CommitStats commitStats = shard.commitStats();
+            final FlushStats flushStats = shard.flushStats();
+            logger.info("--> translog stats [{}] gen [{}] commit_stats [{}] flush_stats [{}/{}]",
+                Strings.toString(translogStats), translog.getGeneration().translogFileGeneration,
+                commitStats.getUserData(), flushStats.getPeriodic(), flushStats.getTotal());
             assertFalse(shard.shouldPeriodicallyFlush());
         });
         assertEquals(0, translog.stats().getUncommittedOperations());