MongoDB 4
This page describes the Optimization Pack for MongoDb version 4.x.
Metrics
Document operations
mongodb_document_deleted
documents/s
The average number of documents deleted per second
mongodb_documents_inserted
documents/s
The average number of documents inserted per second
mongodb_documents_updated
documents/s
The average number of documents updated per second
mongodb_documents_returned
documents/s
The average number of documents returned by queries per second
Other metrics
mongodb_connections_current
connections
The current number of opened connections
mongodb_heap_used
bytes
The total size of heap space used (only available in Linux/Unix systems)
mongodb_mem_used
bytes
The total amount of memory used
mongodb_page_faults_total
faults/s
The average number of page faults per second (i.e., operations that require MongoDB to access data on disk rather than on memory)
mongodb_global_lock_current_queue
ops
The current number of operations queued because of a lock
Parameters
Cache
mongodb_cache_size
megabytes
Integer
You should select your own default value when you create a study, since it is highly dependent on your system (how much memory your system has)
You should select your own default value when you create a study, since it is highly dependent on your system (how much memory your system has)
No
The maximum size of the internal cache that MongoDB (WiredTiger) will use to operate
mongodb_eviction_trigger
percentage
Integer
95
1 → 99
No
The percentage threshold on the use of the MongoDB cache for which cache eviction will start and client threads will throttle
mongodb_eviction_target
percentage
Integer
80
1 → 99
No
The target percentage usage of the MongoDB cache to reach after evictions
mongodb_eviction_dirty_trigger
percentage
Integer
20
1 → 99
No
The percentage threshold on the use of MongoDB dirty cache for which cache eviction will start and client threads will throttle
mongodb_eviction_dirty_target
percentage
Integer
5
1 → 99
No
The target percentage usage of the MongoDB dirty cache to reach after evictions
mongodb_eviction_threads_min
threads
Integer
4
1 → 20
No
The minimum number of threads to use to perform cache eviction
mongodb_eviction_threads_max
threads
Integer
4
1 → 20
No
The maximum number of threads to use to perform cache eviction
Other parameters
mongodb_sync_delay
seconds
Integer
1min
1min → 6min
no
The temporal interval between fsync operations where mongod flushes its working memory to disk
Constraints
Here are some constraints on parameters of MongoDB 4 that avoid common errors in the configuration of a MongoDB deployment:
mongodb_eviction_threads_min <= mongodb_eviction_threads_max
mongodb_eviction_dirty_target <= mongodb_eviction_target
mongodb_eviction_dirty_trigger <= mongodb_eviction_trigger
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