MongoDB WiredTiger Details
WiredTiger Transactions
WiredTiger internal transactions
WiredTiger Cache Activity
Data volume transferred per second between the WT cache and data files. Writes out always imply disk; Reads are often from OS file buffer cache already in RAM, but disk if not.
WiredTiger Block Activity
Data volume handled by the WT block manager per second
WiredTiger Sessions
Internal WT storage engine cursors and sessions currently open
WiredTiger Concurrency Tickets Available
A WT 'ticket' is assigned out for every operation running simultaneously in the WT storage engine. "Available" = hard-coded high value - "Out".
Queued Operations
Operations queued due to a lock.
WiredTiger Checkpoint Time
The time spent in WT checkpoint phase. Warning: This calculation averages the cyclical event (default: 1 min) execution to a per-second value.
WiredTiger Cache Eviction
Least-recently used pages being evicted due to WT cache becoming full.
WiredTiger Cache Capacity
Configured max and current size of the WT cache.
WiredTiger Cache Pages
WiredTiger Log Operations
WT internal write-ahead log operations.
WiredTiger Log Activity
Data volume moved per second in WT internal write-ahead log.
WiredTiger Log Records
Number of records appended per second in WT internal log.
Document Changes
Mixed metrics: Docs per second inserted, updated, deleted or returned on any type of node (primary or secondary); + replicated write Ops/sec; + TTL deletes per second.
Scanned and Moved Objects
This panel shows the number of objects (both data (scanned_objects) and index (scanned)) as well as the number of documents that were moved to a new location due to the size of the document growing. Moved documents only apply to the MMAPv1 storage engine.
Page Faults
Unix or Window memory page faults. Not necessarily from MongoDB.
