Joseph Blomstedt created ZOOKEEPER-3098: -------------------------------------------
Summary: Add additional server metrics Key: ZOOKEEPER-3098 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-3098 Project: ZooKeeper Issue Type: Improvement Components: server Affects Versions: 3.6.0 Reporter: Joseph Blomstedt This patch adds several new server-side metrics as well as makes it easier to add new metrics in the future. This patch also includes a handful of other minor metrics-related changes. Here's a high-level summary of the changes. # This patch extends the request latency tracked in {{ServerStats}} to track {{read}} and {{update}} latency separately. Updates are any request that must be voted on and can change data, reads are all requests that can be handled locally and don't change data. # This patch adds the {{ServerMetrics}} logic and the related {{AvgMinMaxCounter}} and {{SimpleCounter}} classes. This code is designed to make it incredibly easy to add new metrics. To add a new metric you just add one line to {{ServerMetrics}} and then directly reference that new metric anywhere in the code base. The {{ServerMetrics}} logic handles creating the metric, properly adding the metric to the JSON output of the {{/monitor}} admin command, and properly resetting the metric when necessary. The motivation behind {{ServerMetrics}} is to make things easy enough that it encourages new metrics to be added liberally. Lack of in-depth metrics/visibility is a long-standing ZooKeeper weakness. At Facebook, most of our internal changes build on {{ServerMetrics}} and we have nearly 100 internal metrics at this time – all of which we'll be upstreaming in the coming months as we publish more internal patches. # This patch adds 20 new metrics, 14 which are handled by {{ServerMetrics}}. # This patch replaces some uses of {{synchronized}} in {{ServerStats}} with atomic operations. Here's a list of new metrics added in this patch: - {{uptime}}: time that a peer has been in a stable leading/following/observing state - {{leader_uptime}}: uptime for peer in leading state - {{global_sessions}}: count of global sessions - {{local_sessions}}: count of local sessions - {{quorum_size}}: configured ensemble size - {{synced_observers}}: similar to existing `synced_followers` but for observers - {{fsynctime}}: time to fsync transaction log (avg/min/max) - {{snapshottime}}: time to write a snapshot (avg/min/max) - {{dbinittime}}: time to reload database – read snapshot + apply transactions (avg/min/max) - {{readlatency}}: read request latency (avg/min/max) - {{updatelatency}}: update request latency (avg/min/max) - {{propagation_latency}}: end-to-end latency for updates, from proposal on leader to committed-to-datatree on a given host (avg/min/max) - {{follower_sync_time}}: time for follower to sync with leader (avg/min/max) - {{election_time}}: time between entering and leaving election (avg/min/max) - {{looking_count}}: number of transitions into looking state - {{diff_count}}: number of diff syncs performed - {{snap_count}}: number of snap syncs performed - {{commit_count}}: number of commits performed on leader - {{connection_request_count}}: number of incoming client connection requests - {{bytes_received_count}}: similar to existing `packets_received` but tracks bytes -- This message was sent by Atlassian JIRA (v7.6.3#76005)