[SOLR-12652] SolrMetricManager.overridableRegistryName should be removed; it doesn't work

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 7.1
• Fix Version/s: 8.0
• Component/s: metrics
• Assignee: David Smiley
• Reporter: David Smiley
• Created: 09/Aug/18 19:27
• Updated: 08/Jun/19 14:59
• Resolved: 27/Sep/18 19:40

Description

The SolrMetricManager.overridableRegistryName() method is a great idea but unfortunately in practice I've found it doesn't really work; it seems fundamentally flawed. I wish it could work. The main issue I think is that the callers of SMM.registerGauge/registerMetric assumes it can place a gauge/metric and have it be the only once there (force==true). But it won't be if it's shared.

Another problem is in at least one of the reporters – JmxMetricsReporter.JmxListener#registerMBean will get in a race condition to remove an already-registered MBean but in the process of removing it, it'll already get removed concurrently by some other core working on the same name. This results in javax.management.InstanceNotFoundException logged as a warning; nothing serious. But I suspect conceptually there is a problem since which MBean should "win"? Shrug.

Issue Links

• links to: GitHub Pull Request #436