Github user upthewaterspout commented on a diff in the pull request:
https://github.com/apache/incubator-geode/pull/299#discussion_r90077733
--- Diff:
geode-core/src/main/java/org/apache/geode/internal/statistics/StatMonitorHandler.java
---
@@ -50,36 +50,26 @@ public StatMonitorHandler() {
/** Adds a monitor which will be notified of samples */
public boolean addMonitor(StatisticsMonitor monitor) {
- synchronized (this) {
- boolean added = false;
- List<StatisticsMonitor> oldMonitors = this.monitors;
- if (!oldMonitors.contains(monitor)) {
- List<StatisticsMonitor> newMonitors = new
ArrayList<StatisticsMonitor>(oldMonitors);
- added = newMonitors.add(monitor);
- this.monitors = Collections.unmodifiableList(newMonitors);
- }
- if (!this.monitors.isEmpty()) {
- startNotifier_IfEnabledAndNotRunning();
- }
- return added;
+ boolean added = false;
--- End diff --
I don't think it's safe to remove the synchronization here. You're calling
contains followed by add followed by isEmpty. Also, startNotifier_... is
dependent on the state of this.monitors. this.monitors could be getting changed
by other threads at any point in here.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
