[
https://issues.apache.org/jira/browse/DRILL-3171?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15009341#comment-15009341
]
ASF GitHub Bot commented on DRILL-3171:
---------------------------------------
Github user hnfgns commented on a diff in the pull request:
https://github.com/apache/drill/pull/260#discussion_r45108203
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/store/sys/zk/ZkAbstractStore.java
---
@@ -136,7 +138,81 @@ public boolean putIfAbsent(String key, V value) {
}
}
- public abstract void createNodeInZK (String key, V value);
+ /**
+ * Default {@link CreateMode create mode} that will be used in create
operations referred in the see also section.
+ *
+ * @see #createOrUpdate(String, Object)
+ * @see #createWithPrefix(String, Object)
+ */
+ protected abstract CreateMode getCreateMode();
+
+
+ /**
+ * Creates a node in zookeeper with the {@link #getCreateMode() default
create mode} and sets its value if supplied.
+ *
+ * @param path target path
+ * @param value value to set, null if none available
+ *
+ * @see #getCreateMode()
+ * @see #createOrUpdate(String, Object)
+ * @see #withPrefix(String)
+ */
+ protected void createWithPrefix(String path, V value) {
+ createOrUpdate(withPrefix(path), value);
+ }
+
+ /**
+ * Creates a node in zookeeper with the {@link #getCreateMode() default
create mode} and sets its value if supplied
+ * or updates its value if the node already exists.
+ *
+ * Note that if node exists, its mode will not be changed.
+ *
+ * @param path target path
+ * @param value value to set, null if none available
+ *
+ * @see #getCreateMode()
+ * @see #createOrUpdate(String, Object, CreateMode)
+ */
+ protected void createOrUpdate(String path, V value) {
+ createOrUpdate(path, value, getCreateMode());
+ }
+
+ /**
+ * Creates a node in zookeeper with the given mode and sets its value if
supplied or updates its value if the node
+ * already exists.
+ *
+ * Note that if the node exists, its mode will not be changed.
+ *
+ * Internally, the method suppresses {@link
org.apache.zookeeper.KeeperException.NodeExistsException}. It is
+ * safe to do so since the implementation is idempotent.
+ *
+ * @param path target path
+ * @param value value to set, null if none available
+ * @param mode creation mode
+ * @throws RuntimeException throws a {@link RuntimeException} wrapping
the root cause.
+ */
+ protected void createOrUpdate(String path, V value, CreateMode mode) {
+ try {
+ final boolean isUpdate = value != null;
+ final byte[] valueInBytes = isUpdate ?
config.getSerializer().serialize(value) : null;
+ final boolean nodeExists = framework.checkExists().forPath(path) !=
null;
+ if (!nodeExists) {
+ final ACLBackgroundPathAndBytesable<String> creator =
framework.create().withMode(mode);
+ if (isUpdate) {
+ creator.forPath(path, valueInBytes);
+ } else {
+ creator.forPath(path);
+ }
+ } else if (isUpdate) {
+ framework.setData().forPath(path, valueInBytes);
+ }
+ } catch (KeeperException.NodeExistsException ex) {
+ logger.warn("Node already exists in Zookeeper. Skipping... -- [path:
{}, mode: {}]", path, mode);
--- End diff --
We already do handle two cases? i) nodeExists & update ii) !nodeExists &
update.
> Storage Plugins : Two processes tried to update the storage plugin at the
> same time
> -----------------------------------------------------------------------------------
>
> Key: DRILL-3171
> URL: https://issues.apache.org/jira/browse/DRILL-3171
> Project: Apache Drill
> Issue Type: Bug
> Components: Storage - Information Schema
> Affects Versions: 1.0.0
> Reporter: Rahul Challapalli
> Assignee: Deneche A. Hakim
> Labels: test
> Fix For: Future
>
>
> Commit Id# : bd8ac4fca03ad5043bca27fbc7e0dec5a35ac474
> We have seen this issue happen with the below steps
> 1. Clear out the zookeeper
> 2. Update the storage plugin using the rest API on one of the node
> 3. Submit 10 queries concurrently
> With randomized foreman node selection, the node executing the query might
> not have the updated storage plugins info. This could be causing the issue.
> - Rahul
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