Merge branch 'master' into async-errors

* master:
  Add a note to the docs that _cat api `help` option cannot be used if an optional url param is used (elastic#28686)
  Lift error finding utility to exceptions helpers
  Change "tweet" type to "_doc" (elastic#28690)
  [Docs] Add missing word in nested.asciidoc (elastic#28507)
  Simplify the Translog constructor by always expecting an existing translog (elastic#28676)
  Upgrade t-digest to 3.2 (elastic#28295) (elastic#28305)
  Add comment explaining lazy declared versions

docs/reference/aggregations/metrics/percentile-aggregation.asciidoc

@@ -53,13 +53,13 @@ percentiles: `[ 1, 5, 25, 50, 75, 95, 99 ]`.  The response will look like this:
    "aggregations": {
       "load_time_outlier": {
          "values" : {
-            "1.0": 9.9,
-            "5.0": 29.500000000000004,
-            "25.0": 167.5,
+            "1.0": 5.0,
+            "5.0": 25.0,
+            "25.0": 165.0,
             "50.0": 445.0,
-            "75.0": 722.5,
-            "95.0": 940.5,
-            "99.0": 980.1000000000001
+            "75.0": 725.0,
+            "95.0": 945.0,
+            "99.0": 985.0
          }
       }
    }
@@ -129,31 +129,31 @@ Response:
             "values": [
                 {
                     "key": 1.0,
-                    "value": 9.9
+                    "value": 5.0
                 },
                 {
                     "key": 5.0,
-                    "value": 29.500000000000004
+                    "value": 25.0
                 },
                 {
                     "key": 25.0,
-                    "value": 167.5
+                    "value": 165.0
                 },
                 {
                     "key": 50.0,
                     "value": 445.0
                 },
                 {
                     "key": 75.0,
-                    "value": 722.5
+                    "value": 725.0
                 },
                 {
                     "key": 95.0,
-                    "value": 940.5
+                    "value": 945.0
                 },
                 {
                     "key": 99.0,
-                    "value": 980.1000000000001
+                    "value": 985.0
                 }
             ]
         }

docs/reference/cat.asciidoc

@@ -55,7 +55,7 @@ GET /_cat/master?help
 --------------------------------------------------
 // CONSOLE
 
-Might respond respond with:
+Might respond with:
 
 [source,txt]
 --------------------------------------------------
@@ -66,6 +66,11 @@ node | n | node name
 --------------------------------------------------
 // TESTRESPONSE[s/[|]/[|]/ _cat]
 
+NOTE: `help` is not supported if any optional url parameter is used.
+For example `GET _cat/shards/twitter?help` or `GET _cat/indices/twi*?help`
+results in an error. Use `GET _cat/shards?help` or `GET _cat/indices?help`
+instead.
+
 [float]
 [[headers]]
 === Headers

docs/reference/docs/get.asciidoc

@@ -3,7 +3,7 @@
 
 The get API allows to get a typed JSON document from the index based on
 its id. The following example gets a JSON document from an index called
-twitter, under a type called tweet, with id valued 0:
+twitter, under a type called _doc, with id valued 0:
 
 [source,js]
 --------------------------------------------------

docs/reference/indices/flush.asciidoc

@@ -98,7 +98,7 @@ which returns something similar to:
                      "translog_uuid" : "hnOG3xFcTDeoI_kvvvOdNA",
                      "history_uuid" : "XP7KDJGiS1a2fHYiFL5TXQ",
                      "local_checkpoint" : "-1",
-                     "translog_generation" : "1",
+                     "translog_generation" : "2",
                      "max_seq_no" : "-1",
                      "sync_id" : "AVvFY-071siAOuFGEO9P", <1>
                      "max_unsafe_auto_id_timestamp" : "-1"

docs/reference/mapping/types/nested.asciidoc

@@ -184,7 +184,7 @@ The following parameters are accepted by `nested` fields:
 
 Because nested documents are indexed as separate documents, they can only be
 accessed  within the scope of the `nested` query, the
-`nested`/`reverse_nested`, or <<nested-inner-hits,nested inner hits>>.
+`nested`/`reverse_nested` aggregations, or <<nested-inner-hits,nested inner hits>>.
 
 For instance, if a string field within a nested document has
 <<index-options,`index_options`>> set to `offsets` to allow use of the postings

modules/transport-netty4/src/main/java/org/elasticsearch/transport/netty4/Netty4Utils.java

@@ -38,12 +38,9 @@
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
-import java.util.LinkedList;
 import java.util.List;
 import java.util.Locale;
 import java.util.Optional;
-import java.util.Queue;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 public class Netty4Utils {
@@ -171,7 +168,8 @@ public static void closeChannels(final Collection<Channel> channels) throws IOEx
      * @param cause the throwable to test
      */
     public static void maybeDie(final Throwable cause) {
-        final Optional<Error> maybeError = maybeError(cause);
+        final Logger logger = ESLoggerFactory.getLogger(Netty4Utils.class);
+        final Optional<Error> maybeError = ExceptionsHelper.maybeError(cause, logger);
         if (maybeError.isPresent()) {
             /*
              * Here be dragons. We want to rethrow this so that it bubbles up to the uncaught exception handler. Yet, Netty wraps too many
@@ -182,7 +180,6 @@ public static void maybeDie(final Throwable cause) {
             try {
                 // try to log the current stack trace
                 final String formatted = ExceptionsHelper.formatStackTrace(Thread.currentThread().getStackTrace());
-                final Logger logger = ESLoggerFactory.getLogger(Netty4Utils.class);
                 logger.error("fatal error on the network layer\n{}", formatted);
             } finally {
                 new Thread(
@@ -194,40 +191,4 @@ public static void maybeDie(final Throwable cause) {
         }
     }
 
-    static final int MAX_ITERATIONS = 1024;
-
-    /**
-     * Unwrap the specified throwable looking for any suppressed errors or errors as a root cause of the specified throwable.
-     *
-     * @param cause the root throwable
-     *
-     * @return an optional error if one is found suppressed or a root cause in the tree rooted at the specified throwable
-     */
-    static Optional<Error> maybeError(final Throwable cause) {
-        // early terminate if the cause is already an error
-        if (cause instanceof Error) {
-            return Optional.of((Error) cause);
-        }
-
-        final Queue<Throwable> queue = new LinkedList<>();
-        queue.add(cause);
-        int iterations = 0;
-        while (!queue.isEmpty()) {
-            iterations++;
-            if (iterations > MAX_ITERATIONS) {
-                ESLoggerFactory.getLogger(Netty4Utils.class).warn("giving up looking for fatal errors on the network layer", cause);
-                break;
-            }
-            final Throwable current = queue.remove();
-            if (current instanceof Error) {
-                return Optional.of((Error) current);
-            }
-            Collections.addAll(queue, current.getSuppressed());
-            if (current.getCause() != null) {
-                queue.add(current.getCause());
-            }
-        }
-        return Optional.empty();
-    }
-
 }

modules/transport-netty4/src/test/java/org/elasticsearch/transport/netty4/Netty4UtilsTests.java

@@ -22,7 +22,6 @@
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.CompositeByteBuf;
 import io.netty.buffer.Unpooled;
-import io.netty.handler.codec.DecoderException;
 import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.common.bytes.AbstractBytesReferenceTestCase;
 import org.elasticsearch.common.bytes.BytesArray;
@@ -33,9 +32,6 @@
 import org.elasticsearch.test.ESTestCase;
 
 import java.io.IOException;
-import java.util.Optional;
-
-import static org.hamcrest.CoreMatchers.equalTo;
 
 public class Netty4UtilsTests extends ESTestCase {
 
@@ -79,60 +75,6 @@ public void testToChannelBuffer() throws IOException {
         assertArrayEquals(BytesReference.toBytes(ref), BytesReference.toBytes(bytesReference));
     }
 
-    public void testMaybeError() {
-        final Error outOfMemoryError = new OutOfMemoryError();
-        assertError(outOfMemoryError, outOfMemoryError);
-
-        final DecoderException decoderException = new DecoderException(outOfMemoryError);
-        assertError(decoderException, outOfMemoryError);
-
-        final Exception e = new Exception();
-        e.addSuppressed(decoderException);
-        assertError(e, outOfMemoryError);
-
-        final int depth = randomIntBetween(1, 16);
-        Throwable cause = new Exception();
-        boolean fatal = false;
-        Error error = null;
-        for (int i = 0; i < depth; i++) {
-            final int length = randomIntBetween(1, 4);
-            for (int j = 0; j < length; j++) {
-                if (!fatal && rarely()) {
-                    error = new Error();
-                    cause.addSuppressed(error);
-                    fatal = true;
-                } else {
-                    cause.addSuppressed(new Exception());
-                }
-            }
-            if (!fatal && rarely()) {
-                cause = error = new Error(cause);
-                fatal = true;
-            } else {
-                cause = new Exception(cause);
-            }
-        }
-        if (fatal) {
-            assertError(cause, error);
-        } else {
-            assertFalse(Netty4Utils.maybeError(cause).isPresent());
-        }
-
-        assertFalse(Netty4Utils.maybeError(new Exception(new DecoderException())).isPresent());
-
-        Throwable chain = outOfMemoryError;
-        for (int i = 0; i < Netty4Utils.MAX_ITERATIONS; i++) {
-            chain = new Exception(chain);
-        }
-        assertFalse(Netty4Utils.maybeError(chain).isPresent());
-    }
-
-    private void assertError(final Throwable cause, final Error error) {
-        final Optional<Error> maybeError = Netty4Utils.maybeError(cause);
-        assertTrue(maybeError.isPresent());
-        assertThat(maybeError.get(), equalTo(error));
-    }
-
     private BytesReference getRandomizedBytesReference(int length) throws IOException {
         // we know bytes stream output always creates a paged bytes reference, we use it to create randomized content
         ReleasableBytesStreamOutput out = new ReleasableBytesStreamOutput(length, bigarrays);

rest-api-spec/src/main/resources/rest-api-spec/test/indices.stats/20_translog.yml

@@ -15,7 +15,7 @@ setup:
   - do:
       indices.stats:
         metric: [ translog ]
-  - set: { indices.test.primaries.translog.size_in_bytes: empty_size }
+  - set: { indices.test.primaries.translog.size_in_bytes: creation_size }
 
   - do:
       index:
@@ -27,9 +27,11 @@ setup:
   - do:
       indices.stats:
         metric: [ translog ]
-  - gt: { indices.test.primaries.translog.size_in_bytes: $empty_size }
+  - gt: { indices.test.primaries.translog.size_in_bytes: $creation_size }
   - match: { indices.test.primaries.translog.operations: 1 }
-  - gt: { indices.test.primaries.translog.uncommitted_size_in_bytes: $empty_size }
+# we can't check this yet as creation size will contain two empty translog generations. A single
+# non empty generation with one op may be smaller or larger than that.
+#  - gt: { indices.test.primaries.translog.uncommitted_size_in_bytes: $creation_size }
   - match: { indices.test.primaries.translog.uncommitted_operations: 1 }
 
   - do:
@@ -39,9 +41,10 @@ setup:
   - do:
       indices.stats:
         metric: [ translog ]
-  - gt: { indices.test.primaries.translog.size_in_bytes: $empty_size }
+  - gt: { indices.test.primaries.translog.size_in_bytes: $creation_size }
   - match: { indices.test.primaries.translog.operations: 1 }
-  - match: { indices.test.primaries.translog.uncommitted_size_in_bytes: $empty_size }
+  ## creation translog size has some overhead due to an initial empty generation that will be trimmed later
+  - lt: { indices.test.primaries.translog.uncommitted_size_in_bytes: $creation_size }
   - match: { indices.test.primaries.translog.uncommitted_operations: 0 }
 
   - do:
@@ -59,7 +62,8 @@ setup:
   - do:
       indices.stats:
         metric: [ translog ]
-  - match: { indices.test.primaries.translog.size_in_bytes: $empty_size }
+  ## creation translog size has some overhead due to an initial empty generation that will be trimmed later
+  - lte: { indices.test.primaries.translog.size_in_bytes: $creation_size }
   - match: { indices.test.primaries.translog.operations: 0 }
-  - match: { indices.test.primaries.translog.uncommitted_size_in_bytes: $empty_size }
+  - lte: { indices.test.primaries.translog.uncommitted_size_in_bytes: $creation_size }
   - match: { indices.test.primaries.translog.uncommitted_operations: 0 }