This is an automated email from the ASF dual-hosted git repository.
dkuppitz pushed a commit to branch TINKERPOP-2126
in repository https://gitbox.apache.org/repos/asf/tinkerpop.git
commit 62622c28696531206cf57ff9630dd7f9b6e0d3ce
Author: Daniel Kuppitz <daniel_kupp...@hotmail.com>
AuthorDate: Tue Jan 22 15:07:09 2019 -0700
TINKERPOP-2126 Fixed concurrency issue in `ObjectWritable::toString()`.
---
CHANGELOG.asciidoc | 2 +-
docker/Dockerfile | 2 +-
.../hadoop/structure/io/ObjectWritable.java | 33 ++++++++++++++++++++--
3 files changed, 32 insertions(+), 5 deletions(-)
diff --git a/CHANGELOG.asciidoc b/CHANGELOG.asciidoc
index e0e4620..a8b10f0 100644
--- a/CHANGELOG.asciidoc
+++ b/CHANGELOG.asciidoc
@@ -30,7 +30,7 @@
image::https://raw.githubusercontent.com/apache/tinkerpop/master/docs/static/ima
* Added `globalFunctionCacheEnabled` to the `GroovyCompilerGremlinPlugin` to
allow that cache to be disabled.
* Added `globalFunctionCacheEnabled` override to `SessionOpProcessor`
configuration.
* Added status code to `GremlinServerError` so that it would be more directly
accessible during failures.
-* Fixed a concurrency issue in `TraverserSet`.
+* Fixed concurrency issues in `TraverserSet.toString()` and
`ObjectWritable.toString()`.
* Fixed a bug in `InlineFilterStrategy` that mixed up and's and or's when
folding merging conditions together.
[[release-3-3-5]]
diff --git a/docker/Dockerfile b/docker/Dockerfile
index 85c9865..a908b22 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -20,7 +20,7 @@ FROM ubuntu:trusty
MAINTAINER Daniel Kuppitz <m...@gremlin.guru>
RUN apt-get update \
- && apt-get -y install software-properties-common
python-software-properties apt-transport-https curl \
+ && apt-get -y install software-properties-common
python-software-properties apt-transport-https curl dpkg \
&& echo oracle-java8-installer shared/accepted-oracle-license-v1-1 select
true | debconf-set-selections \
&& add-apt-repository -y ppa:webupd8team/java \
&& sh -c 'curl -s
https://packages.microsoft.com/config/ubuntu/14.04/packages-microsoft-prod.deb
-o packages-microsoft-prod.deb' \
diff --git
a/hadoop-gremlin/src/main/java/org/apache/tinkerpop/gremlin/hadoop/structure/io/ObjectWritable.java
b/hadoop-gremlin/src/main/java/org/apache/tinkerpop/gremlin/hadoop/structure/io/ObjectWritable.java
index 0379ee6..979cbfc 100644
---
a/hadoop-gremlin/src/main/java/org/apache/tinkerpop/gremlin/hadoop/structure/io/ObjectWritable.java
+++
b/hadoop-gremlin/src/main/java/org/apache/tinkerpop/gremlin/hadoop/structure/io/ObjectWritable.java
@@ -22,6 +22,8 @@ import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.io.WritableUtils;
import org.apache.tinkerpop.gremlin.process.computer.MapReduce;
import
org.apache.tinkerpop.gremlin.structure.io.gryo.kryoshim.KryoShimServiceLoader;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
import java.io.ByteArrayInputStream;
import java.io.DataInput;
@@ -30,13 +32,16 @@ import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
+import java.util.ConcurrentModificationException;
+import java.util.Objects;
/**
* @author Marko A. Rodriguez (http://markorodriguez.com)
*/
public final class ObjectWritable<T> implements
WritableComparable<ObjectWritable>, Serializable {
- private static final String NULL = "null";
+ private static final Logger logger =
LoggerFactory.getLogger(ObjectWritable.class);
+
private static final ObjectWritable<MapReduce.NullObject>
NULL_OBJECT_WRITABLE = new ObjectWritable<>(MapReduce.NullObject.instance());
T t;
@@ -45,7 +50,7 @@ public final class ObjectWritable<T> implements
WritableComparable<ObjectWritabl
}
public ObjectWritable(final T t) {
- this.t = t;
+ this.set(t);
}
public T get() {
@@ -58,7 +63,29 @@ public final class ObjectWritable<T> implements
WritableComparable<ObjectWritabl
@Override
public String toString() {
- return null == this.t ? NULL : this.t.toString();
+ // Spark's background logging apparently tries to log a `toString()`
of certain objects while they're being
+ // modified, which then throws a ConcurrentModificationException. We
probably can't make any arbitrary object
+ // thread-safe, but we can easily retry on such cases and eventually
we should always get a result.
+ final int maxAttempts = 5;
+ for (int i = maxAttempts; ;) {
+ try {
+ return Objects.toString(this.t);
+ }
+ catch (ConcurrentModificationException cme) {
+ if (--i > 0) {
+ logger.warn(String.format("Failed to toString() object
held by ObjectWritable, retrying %d more %s.",
+ i, i == 1 ? "time" : "times"), cme);
+ } else break;
+ if (i < maxAttempts - 1) {
+ try {
+ Thread.sleep((maxAttempts - i - 1) * 100);
+ } catch (InterruptedException ignored) {
+ break;
+ }
+ }
+ }
+ }
+ return this.t.getClass().toString();
}
@Override
