MongoDB 4
This page describes the Optimization Pack for MongoDb version 4.x.
Metrics
Document operations
| Name | Unit | Description |
|---|---|---|
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
| Name | Unit | Description |
|---|---|---|
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
| Name | Unit | Type | Default | Domain | Restart | Description |
|---|---|---|---|---|---|---|
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
| Name | Unit | Type | Default | Domain | Restart | Description |
|---|---|---|---|---|---|---|
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:
| Constraint |
|---|
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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