Descriptions of metrics for instance monitoring, node monitoring, advanced monitoring, and performance trends - ApsaraDB for MongoDB

This topic describes the metrics supported by the instance monitoring, node monitoring, advanced monitoring, and performance trend features of ApsaraDB for MongoDB. It also explains the meaning of each metric.

Note

For a better display, some values in Bytes are automatically converted to MB, GB, or TB in the console.

Instance monitoring

Note

The supported metrics vary by instance type. For accurate information, see the console.

Metric	Key	Metric name	Metric meaning	Unit	Detailed description	Supported instance types
Disk usage	DiskUsage	disk_usage	Disk usage	%	This metric indicates the disk load of an instance, which is the percentage of the total disk capacity that is used. When your disk usage reaches 80% or more, you can change the instance configuration on the instance details page in the console or refer to High Disk Usage of MongoDB Instances to resolve the issue.	Standalone Replica set Sharded cluster Serverless
Network traffic	MongoDB_Network	bytes_in	Inbound network traffic	Bytes	-
		bytes_out	Outbound network traffic	Bytes	-
		num_requests	Number of requests processed	count	-
Operation QPS	MongoDB_Opcounters	insert	Insert operation QPS	count	The `MongoDB_Opcounters` parameter includes all operations received by the instance, regardless of whether the operations are successfully executed. This parameter records batch operations of the Bulk.insert() type as a single operation. For more fine-grained records, you can refer to the `MongoDB_Documents` metric. For more information, see Opcounters metrics and Repl Opcounters metrics.
		query	Query operation QPS	count
		update	Update operation QPS	count
		delete	Delete operation QPS	count
		getmore	Read operation QPS	count
		command	Protocol command operation QPS	count
Connections	MongoDB_TotalConns	connections_active	Current active connections	count	The number of client connections to the server that are currently performing operations.
		current_conn	Current connections	count	The total number of client connections to the server. This includes connections established by other nodes within the replica set or connections between Mongos and shard nodes.
		connections_totalCreated_ps	Total new connections per second	count	-	Standalone Replica set Sharded cluster
		connections_available	Current available connections	count	-
Connection usage	ConnectionUsage	conn_usage	Connection usage	%	The ratio of the current number of connections to the maximum number of connections. This metric indicates the connection load of the instance. The maximum number of connections varies depending on the instance type of your MongoDB instance. For more information, see Specifications. You can change the instance configuration on the instance details page in the console to increase the connection limit, or refer to How to Query and Limit the Number of Connections to adjust the number of connections on your client.
CPU usage	CpuUsage	cpu_usage	CPU usage	%	The sum of system CPU utilization and user CPU utilization represents the service workload of the instance. High CPU utilization can cause data read and write operations to become abnormally slow and affect normal services. To troubleshoot and resolve this issue, see High CPU utilization on MongoDB instances.
	MongoDB_CpuDetail	cpu_sys	System CPU usage	%	-
	MongoDB_CpuDetail	cpu_user	User CPU usage	%	-
Memory usage	MemoryUsage	mem_usage	Memory usage	%	Memory is primarily consumed by the WiredTiger storage engine, client connections, and request processing. To learn about the causes of high memory usage and optimization strategies, see High memory usage in MongoDB instances.
IOPS usage	MongoDB_IOPS	iops	IOPS usage	times/s	Replica set instances and sharded cluster instances that use cloud disks and run MongoDB 4.2 do not support viewing IOPS usage and IOPS usage rate. The data_iops and log_iops metrics in earlier monitoring versions are merged into iops.
		read_iops	Read IOPS usage	times/s	-
		write_iops	Write IOPS usage	times/s	-
IOPS usage rate	IOPSUsage	iops_usage	IOPS usage rate	%	The ratio of an instance's IOPS usage to the maximum IOPS of its current specifications indicates the service workload of the instance. If the IOPS usage of a MongoDB instance reaches or is close to 100%, the instance may respond slowly and even become unavailable. High IOPS usage on MongoDB instances describes how to view the IOPS usage of a MongoDB instance, the causes of high IOPS usage, and optimization strategies. Note Replica set instances and sharded cluster instances that use cloud disks and run MongoDB 4.2 do not support viewing IOPS usage and IOPS usage rate.
Disk space usage	MongoDB_DetailedSpaceUsage	ins_size	Used disk space	Bytes	For an instance that uses local disks, the used disk space is the sum of the used space on the data disk and the log disk. For an instance that uses cloud disks, the used disk space also includes the space occupied by file system metadata.
		data_size	Used data disk space	Bytes	The space used by the data disk (excluding the local database). This mainly includes physical data files that start with "collection", physical index files that start with "index", and some physical metadata files, such as WiredTiger.wt.
		log_size	Used log disk space	Bytes	The physical size of the local database.
Operation details	MongoDB_OperationDetails	operation_exactIDCount_ps	Number of count operations for a specific ID	count	The number of single update operations that use the `_id` field instead of the shard key on a sharded collection. In the current version, this type of operation causes a traversal of all chunks in the instance. If the number of chunks is large, this can max out the CPU and affect instance performance.
		operation_scanAndOrder_ps	Number of sorting operations that do not use an index	count	The number of sorted queries that cannot use an index to perform the sort operation. A high value can degrade instance performance. To resolve this issue, refer to Best practices for creating indexes in ApsaraDB for MongoDB and create indexes based on your business query conditions.
		operation_writeConflicts_ps	Number of write conflicts	count	The number of queries that encounter write conflicts. A small number of write conflicts usually does not have a significant impact. However, many write conflicts may degrade database performance.
MBPS	MongoDB_Disk_Detail	read_io_bandwidth_mbps	Disk read throughput	MB/s	-
		write_io_bandwidth_mbps	Disk write throughput	MB/s	-
		io_bandwidth_mbps	Total disk throughput	MB/s	The sum of disk read throughput and disk write throughput.
Number of transaction operations	MongoDB_Transactions	trans_totalPrepared_ps	Number of prepared transactions	count	-	Replica set Sharded cluster (Shard only)
		trans_totalPreparedThenCommited_ps	Number of prepared transactions that were successfully committed	count	-
		trans_totalPreparedThenAborted_ps	Number of prepared transactions that were successfully rolled back	count	-
		trans_totalStarted_ps	Number of started transactions	count	-	Standalone Replica set Sharded cluster
		trans_totalCommited_ps	Number of successfully committed transactions	count	-
		trans_totalAborted_ps	Number of successfully rolled back transactions	count	-
		trans_currentActive	Number of current active transactions	count	-
		trans_currentInactive	Number of current inactive transactions	count	-
		trans_currentOpen	Number of current open transactions (not committed or aborted)	count	-
Cursors	MongoDB_AllCursors	total_open	Number of currently open cursors	count	-
		timed_out	Number of cursors closed due to timeout	count	If this value is large, check the client-side business code that processes data.
		job_cursors_closed	Number of cursors closed due to session shutdown	count	-
		pinned_open	Number of currently open and in-use cursors	count	For example, a find or getMore operation pins a cursor to prevent it from being deleted while fetching the next batch of results, and unpins the cursor after returning the results.
		noTimeout_open	Number of currently open and non-timed-out cursors	count	The number of open, non-timed-out cursors created with the noCursorTimeout option. This option prevents a cursor from timing out due to inactivity, but the noCursorTimeout setting is limited by the session timeout. For more information, see the document.	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
WiredTiger	MongoDB_Wt_Cache	bytes_read_into_cache	Bytes read into cache	Bytes	The number of bytes of data read from disk into the WiredTiger cache.
		bytes_written_from_cache	Bytes written from cache	Bytes	The number of bytes of data written from the WiredTiger cache to disk.
		maximum_bytes_configured	Maximum cache size	Bytes	The maximum cache size in bytes configured for the WiredTiger storage engine. To ensure compatibility and security, ApsaraDB for MongoDB sets the CacheSize for WiredTiger to approximately 60% of the memory size of the instance. For more information, see High memory usage of MongoDB instances.
		oplog_bytes_in_cache	Oplog bytes in cache	MB	-
		oplog_bytes_read_into_cache	Oplog bytes read into cache	MB	-
		oplog_bytes_written_from_cache	Oplog bytes written from cache	MB	-
WT concurrent transactions	MongoDB_Wt_Concurrent_Trans	write_concurrent_trans_out	Current concurrent write transactions	count	Before version 7.0, the number of concurrent read and write transactions for an instance was limited to 128, and an availability parameter of 0 for an extended period could indicate an overload. Starting from version 7.0, MongoDB uses a default algorithm to dynamically adjust the maximum number of concurrent storage engine transactions to optimize database throughput during an overload. As a result, an availability parameter of 0 for an extended period does not necessarily indicate an overload. For more information, see the document.
		write_concurrent_trans_available	Available concurrent write transactions	count
		read_concurrent_trans_out	Current concurrent read transactions	count
		read_concurrent_trans_available	Available concurrent read transactions	count
WiredTigerUsage	MongoDB_WTCacheUsage	wt_cache_dirty_usage	WiredTiger dirty cache usage rate	%	For more information, see High memory usage of MongoDB instances.
WiredTigerUsage	MongoDB_WTCacheUsage	wt_cache_usage	WiredTiger cache usage rate	%
Average response time	MongoDB_RT	avg_rt	Total average response time	μs	-
		reads_avg_rt	Average response time for read operations	μs	-
		writes_avg_rt	Average response time for write operations	μs	-
		commands_avg_rt	Average response time for command operations	μs	-
		trans_avg_rt	Average response time for transaction operations	μs	-
Number of affected documents	MongoDB_Documents	document_deleted_ps	Number of deleted documents	count	-
		document_inserted_ps	Number of inserted documents	count	-
		document_returned_ps	Number of returned documents	count	-
		document_updated_ps	Number of updated documents	count	-
GlobalLock	MongoDB_GlobalLocks	gl_ac_readers	Number of active client connections performing read operations	count	-
		gl_ac_writers	Number of active client connections performing write operations	count	-
		gl_cq_writers	Number of operations waiting for a write lock	count	-
		gl_cq_readers	Number of operations waiting for a read lock	count	-
		gl_cq_total	Total number of operations waiting for a lock	count	The sum of the number of operations waiting for a write lock and the number of operations waiting for a read lock. A large value indicates that client operations may be delayed, which can affect application response time.
Number of scanned index entries and documents in queries	MongoDB_QueryExecutors	queryExecutor_scannedObject_ps	Number of documents scanned in queries	count	The total number of documents scanned during query execution and query plan evaluation. This is the same as `totalDocsExamined` in the `explain()` output. A large value indicates that the database needs to scan many non-indexed entries. We recommend creating an index for fields that are frequently scanned.
Number of scanned index entries and documents in queries	MongoDB_QueryExecutors	queryExecutor_scanned_ps	Number of index entries scanned in queries	count	The total number of index entries scanned during query execution and query plan evaluation. This is the same as `explain()` in the `totalKeysExamined` output. If this value is large but the number of returned documents is small, it indicates that the database scanned many index keys to obtain the result documents. This suggests that the index is inefficient. Adjust the index or create other indexes.
TTL	MongoDB_TTLs	ttl_deletedDocuments_ps	Number of documents deleted due to TTL index	count	A high value indicates that many documents are being deleted, which may affect instance performance. For more information, see the referenced document.
TTL	MongoDB_TTLs	ttl_passes_ps	Number of deletions by the background TTL thread	count	The total number of times the TTL background process checks for expired documents. Each time a check is performed, the TTL monitor attempts to delete as many candidate documents as possible from all TTL indexes.
Repl Opcounters	MongoDB_ReplOpcounters	repl_command	Number of Command operations in the replica set	count	During the replication process, MongoDB serializes operations, which can affect the count of each operation. Therefore, the values of the MongoDB_ReplOpcounters and MongoDB_Opcounters counters may be different. For more information, see Opcounters metrics and Repl Opcounters metrics.
		repl_delete	Number of Delete operations in the replica set	count
		repl_getmore	Number of Getmore operations in the replica set	count
		repl_insert	Number of Insert operations in the replica set	count
		repl_query	Number of Query operations in the replica set	count
		repl_update	Number of Update operations in the replica set	count
Number of eviction scans	MongoDB_WtCacheHPCheckEntriesWalked	wiredTiger_cache_hazardPointerCheckEntriesWalked	Number of items in the hazard pointer array scanned during eviction	count	Number of page evictions blocked by hazard pointers during eviction.
Lock Acquisitions	MongoDB_WtLockAcquisitions	wt_checkPoint_lock	Number of checkpoint lock acquisitions	count	-
		wt_dhandle_read_lock	Number of data handle read lock acquisitions	count	If an instance has too many databases and tables, client requests may need to wait a long time for a handle lock, which affects instance performance. For more information, see Instance stuttering or abnormalities caused by too many databases and tables.
		wt_dhandle_write_lock	Number of data handle write lock acquisitions	count
		wt_metadata_lock	Number of metadata lock acquisitions	count
		wt_schema_lock	Number of schema lock acquisitions	count	Frequent operations, such as creating and deleting databases, tables, or indexes, or having an excessive number of databases and tables, can increase schemaLock overhead and affect instance performance. For more information, see Instance stuttering or abnormalities caused by an excessive number of databases and tables.
		wt_table_read_lock	Number of table read lock acquisitions	count	-
		wt_table_write_lock	Number of table write lock acquisitions	count	-
		wt_txn_global_read_lock	Number of transaction global read lock acquisitions	count	-
		wt_txn_global_write_lock	Number of transaction global write lock acquisitions	count	-
MBPS usage rate	MongoDB_MbpsUsage	total_mbps_usage	Disk read/write bandwidth usage rate	%	The ratio of the instance's total disk throughput to its maximum MBPS represents the service payload of the instance. If the MBPS utilization of a MongoDB instance reaches or approaches 100%, it causes slow service responses or even service unavailability. For more information about cloud disk MBPS, see Specifications. Note Supported only for instances that use cloud disks.	Standalone Replica set Sharded cluster (Shard only)
Primary/secondary latency	MongoDB_Repl_Lag	repl_lag	Data synchronization latency between primary and secondary nodes	s	The heartbeat interval between replica set nodes is 2 seconds. Therefore, a repl_lag value between -2 and 2 is normal for replica set instances, and for shard and ConfigServer nodes of sharded cluster instances. The repl_lag value of a secondary node in a replica set instance may be a negative value. This does not mean that the secondary node leads the primary node in the instance in terms of data updates. To obtain the latest status of the primary/secondary latency for the replica set, run rs.printSecondaryReplicationInfo() on the primary node.	Replica set Sharded cluster (Shard and ConfigServer only)
Oplog retention period	MongoDB_OplogTimeInterval	oplog_time_interval	Oplog retention period	h	For MongoDB 4.4 and later, you can adjust the storage.oplogMinRetentionHours parameter on the instance details page.	Replica set Sharded cluster (Shard and ConfigServer only)
moveChunk	MongoDB_MoveChunks	moveChunk_donor_started_ps	The number of times the current node acts as a source for range migration	count	This value increases regardless of whether the migration is successful.	Sharded cluster (Shard only)
		moveChunk_recip_stared_ps	The number of times the current node acts as a destination for range migration	count		Sharded cluster (Shard only)
		moveChunk_deleter_task	Number of chunk range deletion tasks that are ready to run or are running	count	-	Sharded cluster
Number of accesses per second	-	sl_qps	Accesses per second	count	-	Serverless instance
Query executor information	MongoDB_QueryExecutors	collscans_nontailable	Number of full table scans for non-tailable cursors	count	-	Replica set Sharded cluster (excluding Mongos)
Query executor information	MongoDB_QueryExecutors	collscans_total	Total number of full table scans	count	-	Replica set Sharded cluster (excluding Mongos)
Collection and table count information	MongoDB_CollectionNums	admin_user_coll	Number of user tables in the admin database	count	-	Replica set instances of MongoDB 4.2 and earlier Sharded cluster
Number of assertions	MongoDB_Asserts	regular	Normal level	count	The number of assertions that are executed normally.	Standalone Replica set Sharded cluster
		warning	Warning level	count	The number of warning-level assertions. This always returns 0.
		msg	Message level	count	The number of message-level assertions.
		user	User level	count	The number of user-level assertions.
Number of data handles	MongoDB_DataHandle	opened_fd_num	Number of active handles	count	The number of currently active connection data handles in the WiredTiger cache.	Standalone Replica set Sharded cluster
		closed_fd_num	Number of closed handles	count	The number of closed connection data handles scanned in the WiredTiger cache.
		opened_fd_mem	Memory occupied by active handles	MB	The memory occupied by currently active connection data handles in the WiredTiger cache.
Operation latency	MongoDB_Latencys	reads_latency_ps	Latency of successful read requests	us	The latency of all successful requests processed by read operations.	Standalone Replica set Sharded cluster
		writes_latency_ps	Latency of successful write requests	us	The latency of all successful requests processed by write operations, in microseconds (us).
		commands_latency_ps	Latency of successful command requests	us	The latency of all successful requests processed by command operations, in microseconds (us).
		trans_latency_ps	Latency of successful transaction requests	us	The latency of all successful requests processed by transaction operations, in microseconds (us).
TCMalloc memory fragmentation ratio	MongoDB_TcmallocCacheMemRatio	tcmalloc_cache_mem_ratio	TCMalloc memory fragmentation ratio	%	-	Standalone Replica set Sharded cluster
Average time for write concern	MongoDB_GetLastErrorWtime	metrics_getLastError_avg_wtime	Average time spent on write concern operations	ms	The average time spent on write concern operations.	Standalone Replica set Sharded cluster (mongod only)
Average time for write concern	MongoDB_GetLastErrorWtime	metrics_getLastError_wtimeouts	Number of write concern operation timeouts	times	The number of times a write concern operation exceeds the wtimeout threshold.	Standalone Replica set Sharded cluster
Replication buffer size	MongoDB_Repl_Buffer	repl_buffer_size	Current size of the replication buffer	MB	The current size of the replication buffer in the replica set.	Replica set Sharded cluster
Replication buffer size	MongoDB_Repl_Buffer	repl_buffer_max_size	Maximum size of the replication buffer	MB	The maximum size of the replication buffer in the replica set.	Replica set Sharded cluster
Number of evicted pages from WiredTiger cache	MongoDB_WtCacheEviction	pages_selected_count	Number of pages forced for eviction	count	-	Standalone Replica set Sharded cluster
		pages_selected_unable_to_evict_count	Number of pages that cannot be forced for eviction	count	-
		hazard_pointer_blocked_page_eviction	Number of page evictions blocked by hazard pointers	count	-
		max_page_size	Maximum page size encountered during page eviction	MB	-
		pages_evicted_by_application_threads	Number of pages in the WiredTiger cache evicted by user threads	count	-
		history_store_pages_failed_to_evict	History store pages that failed to be evicted	count	-	Replica set Sharded cluster (Shard and ConfigServer only)
		history_store_pages_selected	History store pages selected for eviction	count	-
		pages_written_inMemory_restoration	Number of evicted pages restored in memory	count	-
LockAcquisitions	MongoDB_WtLockAcquisitions	wt_checkPoint_lock	Number of checkpoint lock acquisitions in the WiredTiger cache	count	-	Standalone Replica set Sharded cluster
		wt_dhandle_read_lock	Number of data handle read lock acquisitions in the WiredTiger cache	count	-
		wt_dhandle_write_lock	Number of data handle write lock acquisitions in the WiredTiger cache	count	-
		wt_metadata_lock	Number of metadata lock acquisitions in the WiredTiger cache	count	-
		wt_schema_lock	Number of schema lock acquisitions in the WiredTiger cache	count	-
		wt_table_read_lock	Number of table read lock acquisitions in the WiredTiger cache	count	-
		wt_table_write_lock	Number of table write lock acquisitions in the WiredTiger cache	count	-
		wt_txn_global_read_lock	Number of global read lock acquisitions in the WiredTiger cache	count	-
		wt_txn_global_write_lock	Number of global write lock acquisitions in the WiredTiger cache	count	-
Thread yield	MongoDB_WtCache_Thread_Yield	page_acquire_eviction_blocked	Number of times a thread is blocked waiting for page eviction	times	-	Standalone Replica set Sharded cluster
		page_acquire_locked_blocked	Number of times a thread waits because the target page is locked	times	-
		page_acquire_time_sleeping	Total time a thread is in sleep state while acquiring a page	us	-
WiredTigerUsage	MongoDB_WTCacheUsage	wt_cache_updates_usage	WiredTiger update cache usage rate	%	The ratio of the number of bytes of memory allocated for update operations to the maximum number of bytes in the cache.	Standalone Replica set Sharded cluster
Classic multi-planner execution statistics	MongoDB_MultiPlanner_Worker	metrics_query_multiplanner_classicworks	Total number of jobs	count	The total number of jobs executed in the classic multi-planner.	Replica set Sharded cluster (mongod only)
Logical session cache information	MongoDB_LogicalSession	active_sessions_count	Number of logical sessions in the cache	count	The total number of all logical sessions in the cache since the last refresh.	Replica set Sharded cluster
Page fault information	MongoDB_Page_Faults	page_faults	Number of page fault exceptions	count	-	Standalone Replica set Sharded cluster
Number of operations	MongoDB_Qps	qps	qps	count	-	Standalone Replica set Sharded cluster
MongoDB oplog information	MongoDB_Oplog_Size	oplog_used_size_mb	Current used space of the operation log	MB	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
MongoDB oplog information	MongoDB_Oplog_Size	oplog_max_size_mb	Maximum size of the oplog	MB	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
MongoDB oplog information	MongoDB_Oplog_Size	oplog_min_retention_hours	Minimum oplog retention period	h	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
Memory usage	MongoDB_MemCgroup	cgroup_mem_rss	Memory size occupied by the current MongoDB process	MB	-	Standalone Replica set Sharded cluster
Number of WiredTiger files	MongoDB_StorageDetails	wt_file_num	Current number of collections and tables in the instance	count	Number of collections + Number of indexes	Standalone Replica set Sharded cluster
Classic multi-planner execution statistics	MongoDB_MultiPlanner_Works	metrics_query_multiplanner_classicWorks	Number of queries that use the classic planner (classic planner) during query execution	times	-	Replica set Sharded cluster
TCMalloc memory details	MongoDB_TCMalloc	current_allocated	Number of bytes of memory currently in use	MB/s	-	Standalone Replica set Sharded cluster
TCMalloc memory details	MongoDB_TCMalloc	pageheap_free	Number of bytes of memory available and unallocated in the page heap	MB/s	-	Standalone Replica set Sharded cluster
TCMalloc memory details	MongoDB_TCMalloc	central_cache_free	Number of bytes of memory held in the central free list	MB/s	-	Standalone Replica set Sharded cluster
TCMalloc memory details	MongoDB_TCMalloc	thread_cache_free	Number of bytes of unused memory in the thread-local cache	MB/s	-	Standalone Replica set Sharded cluster
WT engine cursor information	MongoDB_Wt_Cursor	entries_skipped_by_next_calls	Number of entries skipped by in-memory scan next calls	count	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
WT engine cursor information	MongoDB_Wt_Cursor	entries_skipped_by_prev_calls	Number of entries skipped by in-memory scan prev calls	count	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
Network traffic bandwidth utilization	MongoDB_Network_Usage	network_usage	Network traffic bandwidth utilization	%	-	Standalone Replica set Sharded cluster
Native FlowControl information	MongoDB_FlowControl	is_enabled	Indicates whether the FlowControl mechanism is enabled		1 indicates enabled, 0 indicates disabled, and 0.5 indicates not supported.	Replica set Sharded cluster (Shard and ConfigServer only)
Native FlowControl information	MongoDB_FlowControl	is_lagged	Indicates whether FlowControl is currently intervening		1 indicates yes, 0 indicates no, and 0.5 indicates not supported.	Replica set Sharded cluster (Shard and ConfigServer only)
Native FlowControl information	MongoDB_FlowControl	is_lagged_count	Number of FlowControl interventions	times	-	Replica set Sharded cluster (Shard and ConfigServer only)
Native FlowControl information	MongoDB_FlowControl	target_lag_seconds	Tolerable latency for the majority commit point	s	-	Replica set Sharded cluster (Shard and ConfigServer only)
Collection count statistics	MongoDB_CatalogStats	collections	Total number of user collections (excluding system collections)	count	-	Replica set Sharded cluster (Shard and ConfigServer only)
Collection count statistics	MongoDB_CatalogStats	capped	Total number of capped user collections	count	-	Replica set Sharded cluster (Shard and ConfigServer only)
Collection count statistics	MongoDB_CatalogStats	views	Total number of user views	count	-	Replica set Sharded cluster (Shard and ConfigServer only)
Collection Count Statistics	MongoDB_CatalogStats	timeseries	Total number of time series collections	Item	-	ReplicaSet Sharded cluster (supports only Shard and ConfigServer)
Collection count statistics	MongoDB_CatalogStats	shardedCollections	The total number of sharded collections	Count	-	ReplicaSet sharded cluster (supports only shard and Configserver)
Collection count statistics	MongoDB_CatalogStats	internalViews	Total number of views on system collections (collections in the config, admin, or local database)	count	-	Replica set Sharded cluster (Shard and ConfigServer only)
WiredTiger cache capacity	MongoDB_WtCapacity	bytes_written_for_eviction	Size of data written to disk for eviction	MB	-	Replica set Sharded cluster (Shard and ConfigServer only)
Query efficiency	MongoDB_QueryTargeting	query_targeting_objects	Number of documents scanned to return one document	count	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
Query efficiency	MongoDB_QueryTargeting	query_targeting_keys	Number of index entries scanned to return one document	count	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
Command counter	MongoDB_CommandCounters	collStats	Counter for the collStats command	count	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
Command counter	MongoDB_CommandCounters	createIndexes	Counter for the createIndexes command	count	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
Command counter	MongoDB_CommandCounters	listCollections	Counter for the listCollections command	count	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
Command counter	MongoDB_CommandCounters	listDatabases	Counter for the listDatabases command	count	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
Query planCache information	MongoDB_QueryPlanCache	total_size_mb	Memory size occupied by the query plan cache (planCache)	MB	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
Query planCache information	MongoDB_QueryPlanCache	total_query_shapes	Number of different query shapes in the query plan cache (planCache)	count	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
Number of indexed fields on a search node	MongoDB_Search_Field_Indexed	search_field_index_count	Total number of unique fields included in each index of the search node	count	-	Replica set (search node)
Heap memory usage of a search node	MongoDB_Search_Jvm_heap_memory	search_jvm_heap_memory	JVM heap memory size occupied by the search node	MB	-	Replica set (search node)
Number of operations on a search node	MongoDB_Search_Opcounters	search_insert	Number of insert operations on the search node	times	-	Replica set (search node)
Number of operations on a search node	MongoDB_Search_Opcounters	search_delete	Number of delete operations on the search node	times	-	Replica set (search node)
Number of operations on a search node	MongoDB_Search_Opcounters	search_update	Number of update operations on the search node	times	-	Replica set (search node)
Number of operations on a search node	MongoDB_Search_Opcounters	search_Command	Number of command operations on the search node	times	-	Replica set (search node)
Disk space occupied by search node indexes	MongoDB_Search_Disk_Index_Size	search_disk_index_size	Disk space occupied by all indexes on the search node	MB	-	Replica set (search node)
Search node Lucene document information	MongoDB_Search_Lucene_Docs_Max_Size	search_lucene_docs_max_size	Maximum number of Lucene documents contained in a single search index on the search node	count	-	Replica set (search node)
Synchronization latency of a search node	MongoDB_Search_Repl_Lag	search_repl_lag	Synchronization latency of a search node	ms	-	Replica set (search node)
Number of page fault exceptions on a search node	MongoDB_Search_PageFaults	search_pageFaults	Number of page fault exceptions per second on the search node	times	-	Replica set (search node)
Search node query status analysis	MongoDB_Search_Query_Status	search_query_total	Total number of queries on the search node	times	-	Replica set (search node)
Search node query status analysis	MongoDB_Search_Query_Status	search_query_failed	Number of failed queries on the search node	times	-	Replica set (search node)
Search node query status analysis	MongoDB_Search_Query_Status	search_query_successed	Number of successful queries on the search node	times	-	Replica set (search node)

Node monitoring (formerly Basic monitoring)

Note

The supported metrics vary by instance type. For accurate information, see the console.

Metric	Key	Metric name	Metric meaning	Unit	Detailed description	Supported instance types
Disk usage	DiskUsage	disk_usage	Disk usage	%	This metric indicates the disk load of an instance, which is the percentage of the total disk capacity that is used. When your disk usage reaches 80% or more, you can change the instance configuration on the instance details page in the console or refer to High Disk Usage of MongoDB Instances to resolve the issue.	Standalone Replica set Sharded cluster Serverless
Network traffic	MongoDB_Network	bytes_in	Inbound network traffic	Bytes	-
		bytes_out	Outbound network traffic	Bytes	-
		num_requests	Number of requests processed	count	-
Operation QPS	MongoDB_Opcounters	insert	Insert operation QPS	count	The `MongoDB_Opcounters` parameter includes all operations received by the instance, regardless of whether the operations are successfully executed. This parameter records batch operations of the Bulk.insert() type as a single operation. For more fine-grained records, you can refer to the `MongoDB_Documents` metric. For more information, see Opcounters metrics and Repl Opcounters metrics.
		query	Query operation QPS	count
		update	Update operation QPS	count
		delete	Delete operation QPS	count
		getmore	Read operation QPS	count
		command	Protocol command operation QPS	count
Connections	MongoDB_TotalConns	connections_active	Current active connections	count	The number of client connections to the server that are currently performing operations.
		current_conn	Current connections	count	The total number of client connections to the server. This includes connections established by other nodes within the replica set or connections between Mongos and shard nodes.
		connections_totalCreated_ps	Total new connections per second	count	-	Standalone Replica set Sharded cluster
		connections_available	Current available connections	count	-
Connection usage	ConnectionUsage	conn_usage	Connection usage	%	The ratio of the current number of connections to the maximum number of connections. This metric indicates the connection load of the instance. The maximum number of connections varies depending on the instance type of your MongoDB instance. For more information, see Specifications. You can change the instance configuration on the instance details page in the console to increase the connection limit, or refer to How to Query and Limit the Number of Connections to adjust the number of connections on your client.
CPU usage	CpuUsage	cpu_usage	CPU usage	%	The sum of system CPU utilization and user CPU utilization represents the service workload of the instance. High CPU utilization can cause data read and write operations to become abnormally slow and affect normal services. To troubleshoot and resolve this issue, see High CPU utilization on MongoDB instances.
	MongoDB_CpuDetail	cpu_sys	System CPU usage	%	-
	MongoDB_CpuDetail	cpu_user	User CPU usage	%	-
Memory usage	MemoryUsage	mem_usage	Memory usage	%	Memory is primarily consumed by the WiredTiger storage engine, client connections, and request processing. To learn about the causes of high memory usage and optimization strategies, see High memory usage in MongoDB instances.
IOPS usage	MongoDB_IOPS	iops	IOPS usage	times/s	Replica set instances and sharded cluster instances that use cloud disks and run MongoDB 4.2 do not support viewing IOPS usage and IOPS usage rate. The data_iops and log_iops metrics in earlier monitoring versions are merged into iops.
		read_iops	Read IOPS usage	times/s	-
		write_iops	Write IOPS usage	times/s	-
IOPS usage rate	IOPSUsage	iops_usage	IOPS usage rate	%	The ratio of an instance's IOPS usage to the maximum IOPS of its current specifications indicates the service workload of the instance. If the IOPS usage of a MongoDB instance reaches or is close to 100%, the instance may respond slowly and even become unavailable. High IOPS usage on MongoDB instances describes how to view the IOPS usage of a MongoDB instance, the causes of high IOPS usage, and optimization strategies. Note Replica set instances and sharded cluster instances that use cloud disks and run MongoDB 4.2 do not support viewing IOPS usage and IOPS usage rate.
Disk space usage	MongoDB_DetailedSpaceUsage	ins_size	Used disk space	Bytes	For an instance that uses local disks, the used disk space is the sum of the used space on the data disk and the log disk. For an instance that uses cloud disks, the used disk space also includes the space occupied by file system metadata.
		data_size	Used data disk space	Bytes	The space used by the data disk (excluding the local database). This mainly includes physical data files that start with "collection", physical index files that start with "index", and some physical metadata files, such as WiredTiger.wt.
		log_size	Used log disk space	Bytes	The physical size of the local database.
Operation details	MongoDB_OperationDetails	operation_exactIDCount_ps	Number of count operations for a specific ID	count	The number of single update operations that use the `_id` field instead of the shard key on a sharded collection. In the current version, this type of operation causes a traversal of all chunks in the instance. If the number of chunks is large, this can max out the CPU and affect instance performance.
		operation_scanAndOrder_ps	Number of sorting operations that do not use an index	count	The number of sorted queries that cannot use an index to perform the sort operation. A high value can degrade instance performance. To resolve this issue, refer to Best practices for creating indexes in ApsaraDB for MongoDB and create indexes based on your business query conditions.
		operation_writeConflicts_ps	Number of write conflicts	count	The number of queries that encounter write conflicts. A small number of write conflicts usually does not have a significant impact. However, many write conflicts may degrade database performance.
MBPS	MongoDB_Disk_Detail	read_io_bandwidth_mbps	Disk read throughput	MB/s	-
		write_io_bandwidth_mbps	Disk write throughput	MB/s	-
		io_bandwidth_mbps	Total disk throughput	MB/s	The sum of disk read throughput and disk write throughput.
Number of transaction operations	MongoDB_Transactions	trans_totalPrepared_ps	Number of prepared transactions	count	-	Replica set Sharded cluster (Shard only)
		trans_totalPreparedThenCommited_ps	Number of prepared transactions that were successfully committed	count	-
		trans_totalPreparedThenAborted_ps	Number of prepared transactions that were successfully rolled back	count	-
		trans_totalStarted_ps	Number of started transactions	count	-	Standalone Replica set Sharded cluster
		trans_totalCommited_ps	Number of successfully committed transactions	count	-
		trans_totalAborted_ps	Number of successfully rolled back transactions	count	-
		trans_currentActive	Number of current active transactions	count	-
		trans_currentInactive	Number of current inactive transactions	count	-
		trans_currentOpen	Number of current open transactions (not committed or aborted)	count	-
Cursors	MongoDB_AllCursors	total_open	Number of currently open cursors	count	-
		timed_out	Number of cursors closed due to timeout	count	If this value is large, check the client-side business code that processes data.
		job_cursors_closed	Number of cursors closed due to session shutdown	count	-
		pinned_open	Number of currently open and in-use cursors	count	For example, a find or getMore operation pins a cursor to prevent it from being deleted while fetching the next batch of results, and unpins the cursor after returning the results.
		noTimeout_open	Number of currently open and non-timed-out cursors	count	The number of open, non-timed-out cursors created with the noCursorTimeout option. This option prevents a cursor from timing out due to inactivity, but the noCursorTimeout setting is limited by the session timeout. For more information, see the document.	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
WiredTiger	MongoDB_Wt_Cache	bytes_read_into_cache	Bytes read into cache	Bytes	The number of bytes of data read from disk into the WiredTiger cache.
		bytes_written_from_cache	Bytes written from cache	Bytes	The number of bytes of data written from the WiredTiger cache to disk.
		maximum_bytes_configured	Maximum cache size	Bytes	The maximum cache size in bytes configured for the WiredTiger storage engine. To ensure compatibility and security, ApsaraDB for MongoDB sets the CacheSize for WiredTiger to approximately 60% of the memory size of the instance. For more information, see High memory usage of MongoDB instances.
		oplog_bytes_in_cache	Oplog bytes in cache	MB	-
		oplog_bytes_read_into_cache	Oplog bytes read into cache	MB	-
		oplog_bytes_written_from_cache	Oplog bytes written from cache	MB	-
WT concurrent transactions	MongoDB_Wt_Concurrent_Trans	write_concurrent_trans_out	Current concurrent write transactions	count	Before version 7.0, the number of concurrent read and write transactions for an instance was limited to 128, and an availability parameter of 0 for an extended period could indicate an overload. Starting from version 7.0, MongoDB uses a default algorithm to dynamically adjust the maximum number of concurrent storage engine transactions to optimize database throughput during an overload. As a result, an availability parameter of 0 for an extended period does not necessarily indicate an overload. For more information, see the document.
		write_concurrent_trans_available	Available concurrent write transactions	count
		read_concurrent_trans_out	Current concurrent read transactions	count
		read_concurrent_trans_available	Available concurrent read transactions	count
WiredTigerUsage	MongoDB_WTCacheUsage	wt_cache_dirty_usage	WiredTiger dirty cache usage rate	%	For more information, see High memory usage of MongoDB instances.
WiredTigerUsage	MongoDB_WTCacheUsage	wt_cache_usage	WiredTiger cache usage rate	%
Average response time	MongoDB_RT	avg_rt	Total average response time	μs	-
		reads_avg_rt	Average response time for read operations	μs	-
		writes_avg_rt	Average response time for write operations	μs	-
		commands_avg_rt	Average response time for command operations	μs	-
		trans_avg_rt	Average response time for transaction operations	μs	-
Number of affected documents	MongoDB_Documents	document_deleted_ps	Number of deleted documents	count	-
		document_inserted_ps	Number of inserted documents	count	-
		document_returned_ps	Number of returned documents	count	-
		document_updated_ps	Number of updated documents	count	-
GlobalLock	MongoDB_GlobalLocks	gl_ac_readers	Number of active client connections performing read operations	count	-
		gl_ac_writers	Number of active client connections performing write operations	count	-
		gl_cq_writers	Number of operations waiting for a write lock	count	-
		gl_cq_readers	Number of operations waiting for a read lock	count	-
		gl_cq_total	Total number of operations waiting for a lock	count	The sum of the number of operations waiting for a write lock and the number of operations waiting for a read lock. A large value indicates that client operations may be delayed, which can affect application response time.
Number of scanned index entries and documents in queries	MongoDB_QueryExecutors	queryExecutor_scannedObject_ps	Number of documents scanned in queries	count	The total number of documents scanned during query execution and query plan evaluation. This is the same as `totalDocsExamined` in the `explain()` output. A large value indicates that the database needs to scan many non-indexed entries. We recommend creating an index for fields that are frequently scanned.
Number of scanned index entries and documents in queries	MongoDB_QueryExecutors	queryExecutor_scanned_ps	Number of index entries scanned in queries	count	The total number of index entries scanned during query execution and query plan evaluation. This is the same as `explain()` in the `totalKeysExamined` output. If this value is large but the number of returned documents is small, it indicates that the database scanned many index keys to obtain the result documents. This suggests that the index is inefficient. Adjust the index or create other indexes.
TTL	MongoDB_TTLs	ttl_deletedDocuments_ps	Number of documents deleted due to TTL index	count	A high value indicates that many documents are being deleted, which may affect instance performance. For more information, see the referenced document.
TTL	MongoDB_TTLs	ttl_passes_ps	Number of deletions by the background TTL thread	count	The total number of times the TTL background process checks for expired documents. Each time a check is performed, the TTL monitor attempts to delete as many candidate documents as possible from all TTL indexes.
Repl Opcounters	MongoDB_ReplOpcounters	repl_command	Number of Command operations in the replica set	count	During the replication process, MongoDB serializes operations, which can affect the count of each operation. Therefore, the values of the MongoDB_ReplOpcounters and MongoDB_Opcounters counters may be different. For more information, see Opcounters metrics and Repl Opcounters metrics.
		repl_delete	Number of Delete operations in the replica set	count
		repl_getmore	Number of Getmore operations in the replica set	count
		repl_insert	Number of Insert operations in the replica set	count
		repl_query	Number of Query operations in the replica set	count
		repl_update	Number of Update operations in the replica set	count
Number of eviction scans	MongoDB_WtCacheHPCheckEntriesWalked	wiredTiger_cache_hazardPointerCheckEntriesWalked	Number of items in the hazard pointer array scanned during eviction	count	Number of page evictions blocked by hazard pointers during eviction.
Lock Acquisitions	MongoDB_WtLockAcquisitions	wt_checkPoint_lock	Number of checkpoint lock acquisitions	count	-
		wt_dhandle_read_lock	Number of data handle read lock acquisitions	count	If an instance has too many databases and tables, client requests may need to wait a long time for a handle lock, which affects instance performance. For more information, see Instance stuttering or abnormalities caused by too many databases and tables.
		wt_dhandle_write_lock	Number of data handle write lock acquisitions	count
		wt_metadata_lock	Number of metadata lock acquisitions	count
		wt_schema_lock	Number of schema lock acquisitions	count	Frequent operations, such as creating and deleting databases, tables, or indexes, or having an excessive number of databases and tables, can increase schemaLock overhead and affect instance performance. For more information, see Instance stuttering or abnormalities caused by an excessive number of databases and tables.
		wt_table_read_lock	Number of table read lock acquisitions	count	-
		wt_table_write_lock	Number of table write lock acquisitions	count	-
		wt_txn_global_read_lock	Number of transaction global read lock acquisitions	count	-
		wt_txn_global_write_lock	Number of transaction global write lock acquisitions	count	-
MBPS usage rate	MongoDB_MbpsUsage	total_mbps_usage	Disk read/write bandwidth usage rate	%	The ratio of the instance's total disk throughput to its maximum MBPS represents the service payload of the instance. If the MBPS utilization of a MongoDB instance reaches or approaches 100%, it causes slow service responses or even service unavailability. For more information about cloud disk MBPS, see Specifications. Note Supported only for instances that use cloud disks.	Standalone Replica set Sharded cluster (Shard only)
Primary/secondary latency	MongoDB_Repl_Lag	repl_lag	Data synchronization latency between primary and secondary nodes	s	The heartbeat interval between replica set nodes is 2 seconds. Therefore, a repl_lag value between -2 and 2 is normal for replica set instances, and for shard and ConfigServer nodes of sharded cluster instances. The repl_lag value of a secondary node in a replica set instance may be a negative value. This does not mean that the secondary node leads the primary node in the instance in terms of data updates. To obtain the latest status of the primary/secondary latency for the replica set, run rs.printSecondaryReplicationInfo() on the primary node.	Replica set Sharded cluster (Shard and ConfigServer only)
Oplog retention period	MongoDB_OplogTimeInterval	oplog_time_interval	Oplog retention period	h	For MongoDB 4.4 and later, you can adjust the storage.oplogMinRetentionHours parameter on the instance details page.	Replica set Sharded cluster (Shard and ConfigServer only)
moveChunk	MongoDB_MoveChunks	moveChunk_donor_started_ps	The number of times the current node acts as a source for range migration	count	This value increases regardless of whether the migration is successful.	Sharded cluster (Shard only)
		moveChunk_recip_stared_ps	The number of times the current node acts as a destination for range migration	count		Sharded cluster (Shard only)
		moveChunk_deleter_task	Number of chunk range deletion tasks that are ready to run or are running	count	-	Sharded cluster
Number of accesses per second	-	sl_qps	Accesses per second	count	-	Serverless instance
Query executor information	MongoDB_QueryExecutors	collscans_nontailable	Number of full table scans for non-tailable cursors	count	-	Replica set Sharded cluster (excluding Mongos)
Query executor information	MongoDB_QueryExecutors	collscans_total	Total number of full table scans	count	-	Replica set Sharded cluster (excluding Mongos)
Collection and table count information	MongoDB_CollectionNums	admin_user_coll	Number of user tables in the admin database	count	-	Replica set instances of MongoDB 4.2 and earlier Sharded cluster
Number of assertions	MongoDB_Asserts	regular	Normal level	count	The number of assertions that are executed normally.	Standalone Replica set Sharded cluster
		warning	Warning level	count	The number of warning-level assertions. This always returns 0.
		msg	Message level	count	The number of message-level assertions.
		user	User level	count	The number of user-level assertions.
Number of data handles	MongoDB_DataHandle	opened_fd_num	Number of active handles	count	The number of currently active connection data handles in the WiredTiger cache.	Standalone Replica set Sharded cluster
		closed_fd_num	Number of closed handles	count	The number of closed connection data handles scanned in the WiredTiger cache.
		opened_fd_mem	Memory occupied by active handles	MB	The memory occupied by currently active connection data handles in the WiredTiger cache.
Operation latency	MongoDB_Latencys	reads_latency_ps	Latency of successful read requests	us	The latency of all successful requests processed by read operations.	Standalone Replica set Sharded cluster
		writes_latency_ps	Latency of successful write requests	us	The latency of all successful requests processed by write operations, in microseconds (us).
		commands_latency_ps	Latency of successful command requests	us	The latency of all successful requests processed by command operations, in microseconds (us).
		trans_latency_ps	Latency of successful transaction requests	us	The latency of all successful requests processed by transaction operations, in microseconds (us).
TCMalloc memory fragmentation ratio	MongoDB_TcmallocCacheMemRatio	tcmalloc_cache_mem_ratio	TCMalloc memory fragmentation ratio	%	-	Standalone Replica set Sharded cluster
Average time for write concern	MongoDB_GetLastErrorWtime	metrics_getLastError_avg_wtime	Average time spent on write concern operations	ms	The average time spent on write concern operations.	Standalone Replica set Sharded cluster (mongod only)
Average time for write concern	MongoDB_GetLastErrorWtime	metrics_getLastError_wtimeouts	Number of write concern operation timeouts	times	The number of times a write concern operation exceeds the wtimeout threshold.	Standalone Replica set Sharded cluster
Replication buffer size	MongoDB_Repl_Buffer	repl_buffer_size	Current size of the replication buffer	MB	The current size of the replication buffer in the replica set.	Replica set Sharded cluster
Replication buffer size	MongoDB_Repl_Buffer	repl_buffer_max_size	Maximum size of the replication buffer	MB	The maximum size of the replication buffer in the replica set.	Replica set Sharded cluster
Number of evicted pages from WiredTiger cache	MongoDB_WtCacheEviction	pages_selected_count	Number of pages forced for eviction	count	-	Standalone Replica set Sharded cluster
		pages_selected_unable_to_evict_count	Number of pages that cannot be forced for eviction	count	-
		hazard_pointer_blocked_page_eviction	Number of page evictions blocked by hazard pointers	count	-
		max_page_size	Maximum page size encountered during page eviction	MB	-
		pages_evicted_by_application_threads	Number of pages in the WiredTiger cache evicted by user threads	count	-
		history_store_pages_failed_to_evict	History store pages that failed to be evicted	count	-	Replica set Sharded cluster (Shard and ConfigServer only)
		history_store_pages_selected	History store pages selected for eviction	count	-
		pages_written_inMemory_restoration	Number of evicted pages restored in memory	count	-
LockAcquisitions	MongoDB_WtLockAcquisitions	wt_checkPoint_lock	Number of checkpoint lock acquisitions in the WiredTiger cache	count	-	Standalone Replica set Sharded cluster
		wt_dhandle_read_lock	Number of data handle read lock acquisitions in the WiredTiger cache	count	-
		wt_dhandle_write_lock	Number of data handle write lock acquisitions in the WiredTiger cache	count	-
		wt_metadata_lock	Number of metadata lock acquisitions in the WiredTiger cache	count	-
		wt_schema_lock	Number of schema lock acquisitions in the WiredTiger cache	count	-
		wt_table_read_lock	Number of table read lock acquisitions in the WiredTiger cache	count	-
		wt_table_write_lock	Number of table write lock acquisitions in the WiredTiger cache	count	-
		wt_txn_global_read_lock	Number of global read lock acquisitions in the WiredTiger cache	count	-
		wt_txn_global_write_lock	Number of global write lock acquisitions in the WiredTiger cache	count	-
Thread yield	MongoDB_WtCache_Thread_Yield	page_acquire_eviction_blocked	Number of times a thread is blocked waiting for page eviction	times	-	Standalone Replica set Sharded cluster
		page_acquire_locked_blocked	Number of times a thread waits because the target page is locked	times	-
		page_acquire_time_sleeping	Total time a thread is in sleep state while acquiring a page	us	-
WiredTigerUsage	MongoDB_WTCacheUsage	wt_cache_updates_usage	WiredTiger update cache usage rate	%	The ratio of the number of bytes of memory allocated for update operations to the maximum number of bytes in the cache.	Standalone Replica set Sharded cluster
Classic multi-planner execution statistics	MongoDB_MultiPlanner_Worker	metrics_query_multiplanner_classicworks	Total number of jobs	count	The total number of jobs executed in the classic multi-planner.	Replica set Sharded cluster (mongod only)
Logical session cache information	MongoDB_LogicalSession	active_sessions_count	Number of logical sessions in the cache	count	The total number of all logical sessions in the cache since the last refresh.	Replica set Sharded cluster
Page fault information	MongoDB_Page_Faults	page_faults	Number of page fault exceptions	count	-	Standalone Replica set Sharded cluster
Number of operations	MongoDB_Qps	qps	qps	count	-	Standalone Replica set Sharded cluster
MongoDB oplog information	MongoDB_Oplog_Size	oplog_used_size_mb	Current used space of the operation log	MB	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
MongoDB oplog information	MongoDB_Oplog_Size	oplog_max_size_mb	Maximum size of the oplog	MB	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
MongoDB oplog information	MongoDB_Oplog_Size	oplog_min_retention_hours	Minimum oplog retention period	h	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
Memory usage	MongoDB_MemCgroup	cgroup_mem_rss	Memory size occupied by the current MongoDB process	MB	-	Standalone Replica set Sharded cluster
Number of WiredTiger files	MongoDB_StorageDetails	wt_file_num	Current number of collections and tables in the instance	count	Number of collections + Number of indexes	Standalone Replica set Sharded cluster
Classic multi-planner execution statistics	MongoDB_MultiPlanner_Works	metrics_query_multiplanner_classicWorks	Number of queries that use the classic planner (classic planner) during query execution	times	-	Replica set Sharded cluster
TCMalloc memory details	MongoDB_TCMalloc	current_allocated	Number of bytes of memory currently in use	MB/s	-	Standalone Replica set Sharded cluster
TCMalloc memory details	MongoDB_TCMalloc	pageheap_free	Number of bytes of memory available and unallocated in the page heap	MB/s	-	Standalone Replica set Sharded cluster
TCMalloc memory details	MongoDB_TCMalloc	central_cache_free	Number of bytes of memory held in the central free list	MB/s	-	Standalone Replica set Sharded cluster
TCMalloc memory details	MongoDB_TCMalloc	thread_cache_free	Number of bytes of unused memory in the thread-local cache	MB/s	-	Standalone Replica set Sharded cluster
WT engine cursor information	MongoDB_Wt_Cursor	entries_skipped_by_next_calls	Number of entries skipped by in-memory scan next calls	count	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
WT engine cursor information	MongoDB_Wt_Cursor	entries_skipped_by_prev_calls	Number of entries skipped by in-memory scan prev calls	count	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
Network traffic bandwidth utilization	MongoDB_Network_Usage	network_usage	Network traffic bandwidth utilization	%	-	Standalone Replica set Sharded cluster
Native FlowControl information	MongoDB_FlowControl	is_enabled	Indicates whether the FlowControl mechanism is enabled		1 indicates enabled, 0 indicates disabled, and 0.5 indicates not supported.	Replica set Sharded cluster (Shard and ConfigServer only)
Native FlowControl information	MongoDB_FlowControl	is_lagged	Indicates whether FlowControl is currently intervening		1 indicates yes, 0 indicates no, and 0.5 indicates not supported.	Replica set Sharded cluster (Shard and ConfigServer only)
Native FlowControl information	MongoDB_FlowControl	is_lagged_count	Number of FlowControl interventions	times	-	Replica set Sharded cluster (Shard and ConfigServer only)
Native FlowControl information	MongoDB_FlowControl	target_lag_seconds	Tolerable latency for the majority commit point	s	-	Replica set Sharded cluster (Shard and ConfigServer only)
Collection count statistics	MongoDB_CatalogStats	collections	Total number of user collections (excluding system collections)	count	-	Replica set Sharded cluster (Shard and ConfigServer only)
Collection count statistics	MongoDB_CatalogStats	capped	Total number of capped user collections	count	-	Replica set Sharded cluster (Shard and ConfigServer only)
Collection count statistics	MongoDB_CatalogStats	views	Total number of user views	count	-	Replica set Sharded cluster (Shard and ConfigServer only)
Collection Count Statistics	MongoDB_CatalogStats	timeseries	Total number of time series collections	Item	-	ReplicaSet Sharded cluster (supports only Shard and ConfigServer)
Collection count statistics	MongoDB_CatalogStats	shardedCollections	The total number of sharded collections	Count	-	ReplicaSet sharded cluster (supports only shard and Configserver)
Collection count statistics	MongoDB_CatalogStats	internalViews	Total number of views on system collections (collections in the config, admin, or local database)	count	-	Replica set Sharded cluster (Shard and ConfigServer only)
WiredTiger cache capacity	MongoDB_WtCapacity	bytes_written_for_eviction	Size of data written to disk for eviction	MB	-	Replica set Sharded cluster (Shard and ConfigServer only)
Query efficiency	MongoDB_QueryTargeting	query_targeting_objects	Number of documents scanned to return one document	count	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
Query efficiency	MongoDB_QueryTargeting	query_targeting_keys	Number of index entries scanned to return one document	count	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
Command counter	MongoDB_CommandCounters	collStats	Counter for the collStats command	count	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
Command counter	MongoDB_CommandCounters	createIndexes	Counter for the createIndexes command	count	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
Command counter	MongoDB_CommandCounters	listCollections	Counter for the listCollections command	count	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
Command counter	MongoDB_CommandCounters	listDatabases	Counter for the listDatabases command	count	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
Query planCache information	MongoDB_QueryPlanCache	total_size_mb	Memory size occupied by the query plan cache (planCache)	MB	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
Query planCache information	MongoDB_QueryPlanCache	total_query_shapes	Number of different query shapes in the query plan cache (planCache)	count	-	Standalone Replica set Sharded cluster (Shard and ConfigServer only)
Number of indexed fields on a search node	MongoDB_Search_Field_Indexed	search_field_index_count	Total number of unique fields included in each index of the search node	count	-	Replica set (search node)
Heap memory usage of a search node	MongoDB_Search_Jvm_heap_memory	search_jvm_heap_memory	JVM heap memory size occupied by the search node	MB	-	Replica set (search node)
Number of operations on a search node	MongoDB_Search_Opcounters	search_insert	Number of insert operations on the search node	times	-	Replica set (search node)
Number of operations on a search node	MongoDB_Search_Opcounters	search_delete	Number of delete operations on the search node	times	-	Replica set (search node)
Number of operations on a search node	MongoDB_Search_Opcounters	search_update	Number of update operations on the search node	times	-	Replica set (search node)
Number of operations on a search node	MongoDB_Search_Opcounters	search_Command	Number of command operations on the search node	times	-	Replica set (search node)
Disk space occupied by search node indexes	MongoDB_Search_Disk_Index_Size	search_disk_index_size	Disk space occupied by all indexes on the search node	MB	-	Replica set (search node)
Search node Lucene document information	MongoDB_Search_Lucene_Docs_Max_Size	search_lucene_docs_max_size	Maximum number of Lucene documents contained in a single search index on the search node	count	-	Replica set (search node)
Synchronization latency of a search node	MongoDB_Search_Repl_Lag	search_repl_lag	Synchronization latency of a search node	ms	-	Replica set (search node)
Number of page fault exceptions on a search node	MongoDB_Search_PageFaults	search_pageFaults	Number of page fault exceptions per second on the search node	times	-	Replica set (search node)
Search node query status analysis	MongoDB_Search_Query_Status	search_query_total	Total number of queries on the search node	times	-	Replica set (search node)
Search node query status analysis	MongoDB_Search_Query_Status	search_query_failed	Number of failed queries on the search node	times	-	Replica set (search node)
Search node query status analysis	MongoDB_Search_Query_Status	search_query_successed	Number of successful queries on the search node	times	-	Replica set (search node)

Advanced monitoring

Note

Only standalone, replica set, and sharded cluster instances support Advanced Monitoring.
The supported metrics vary by instance type. For accurate information, see the console.

Supported instances	Metric	Metric and description	Description	Unit
Standalone instance Replica set instance Sharded cluster instance	CPU usage	cpu_usage	The CPU usage of the instance.	%
	Memory usage	mem_usage	The memory usage of the instance.	%
	Disk space usage	ins_size	Total used space.	Bytes
		data_size	Used data disk space.	Bytes
		log_size	Used log disk space.	Bytes
	Connection usage	conn_usage	The ratio of the current number of connections to the maximum number of connections for the instance.	%
	cursors	open_no_timedout	Number of currently open cursors with no timeout.	count
		pinned_open	Number of currently in-use cursors.	count
		open_total	Number of currently open cursors.	count
		closed_by_timeout	Number of cursors closed due to timeout.	count
		closed_by_session	Number of cursors closed due to session shutdown.	count
	Read/write queue	currentQueue_total	Total number of operations waiting for a lock.	count
		currentQueue_readers	Number of operations waiting for a read lock.	count
		currentQueue_writers	Number of operations waiting for a write lock.	count
		active_readers	Number of active client connections performing read operations.	count
		active_writers	Number of active client connections performing write operations.	count
	Average response time (MongoDB_RT)	avg_RT	Average response time of the instance.	μs
		reads_avg_rt	Average response time for read operations.	μs
		writes_avg_rt	Average response time for write operations.	μs
		commands_avg_rt	Average response time for command operations.	μs
		trans_avg_rt	Average response time for transaction operations.	μs
	WiredTiger request queue	write_concurrent_trans_out	Number of concurrent write requests.	count
		read_concurrent_trans_out	Number of concurrent read requests.	count
		write_concurrent_trans_available	Number of available concurrent write operations.	count
		read_concurrent_trans_available	Number of available concurrent read operations.	count
	I/O latency	iocheck_cost:	The current I/O response performance. Note Supported only for standalone instances and replica set instances running MongoDB 4.0 or earlier.	ms
	WiredTigerCache usage rate	wt_cache_usage	WiredTiger cache usage rate.	%
	WiredTigerCache usage rate	wt_cache_dirty_usage	WiredTiger dirty cache usage rate.	%
	Number of affected documents	deletedDocuments	Number of deleted documents.	count
		insertedDocuments	Number of inserted documents.	count
		returnDocuments	Number of returned documents.	count
		updatedDocuments	Number of updated documents.	count
	Operation details	scanAndOrder	Number of requests that cannot use an index for sorting.	count
		writeConflicts	Number of write conflicts.	count
		exactIDCount	Number of requests that need to obtain matching _id information through broadcasting.	count
	Number of scanned index entries and documents in queries	scannedKeys	Number of index entries scanned in queries.	count
	Number of scanned index entries and documents in queries	scannedDocs	Number of documents scanned in queries.	count
	TTL	ttlDeletedDocuments	Number of documents deleted due to TTL index.	count
	TTL	ttlPasses	Number of deletions by the background TTL thread.	count
	Lock Acquisitions	wiredTiger_schema_lock_delta	Number of schema lock acquisitions.	count
		wiredTiger_metadata_lock_delta	Number of metadata lock acquisitions.	count
		wiredTiger_table_read_lock_delta	Number of table read lock acquisitions.	count
		wiredTiger_table_write_lock_delta	Number of table write lock acquisitions.	count
		wiredTiger_txn_global_read_lock_delta	Number of transaction global read lock acquisitions.	count
		wiredTiger_txn_global_write_lock_delta	Number of transaction global write lock acquisitions.	count
	MBPS	read_io_bandwidth_mbps	Disk read throughput.	MB/s
		write_io_bandwidth_mbps	Disk write throughput.	MB/s
		io_bandwidth_mbps	Total disk throughput.	MB/s
	Number of transaction operations	trans_totalPrepared_ps	Number of prepared transactions.	count
		trans_totalPreparedThenCommited_ps	Prepared transactions that were successfully committed.	count
		trans_totalPreparedThenAborted_ps	Number of prepared transactions that were successfully rolled back.	count
		trans_totalStarted_ps	Number of started transactions.	count
		trans_totalCommited_ps	Number of successfully committed transactions.	count
		trans_totalAborted_ps	Number of successfully rolled back transactions.	count
	MBPS usage rate	total_mbps_usage:	Disk read/write bandwidth usage rate. Note Supported only for instances that use cloud disks. For sharded cluster instances, this metric is valid only for the shard component.	%
	WiredTiger	bytes_read_into_cache	Amount of data read into the cache.	Bytes
		bytes_written_from_cache	Size of data written from the cache to disk.	Bytes
		maximum_bytes_configured	Maximum configured disk size.	Bytes
	Disk usage	disk_usage	The ratio of the total used space to the maximum available space for the instance.	%
	Operation QPS	insert	Number of insert operations.	count
		query	Number of query operations.	count
		update	Number of update operations.	count
		delete	Number of delete operations.	count
		getmore	Number of read operations.	count
command		Number of protocol command operations.	count
Connections	current_conn	Total current connections of the instance.	count
Connections	active_conn	Current active connections of the instance.	count
Network traffic	bytes_in	Inbound traffic.	Bytes
Network traffic	bytes_out	Outbound traffic.	Bytes
Replica set instance Sharded cluster instance	IOPS usage	data_iops(iops)	IOPS usage. Note Instances that use cloud disks and run MongoDB 4.2 do not support viewing IOPS usage and IOPS usage rate. The data_iops and log_iops metrics in earlier monitoring versions are now merged into data_iops(iops).	times/s
	IOPS usage rate	iops_usage	The ratio of the IOPS usage of the instance to the maximum available IOPS. Note Instances that use cloud disks and run MongoDB 4.2 do not support viewing IOPS usage and IOPS usage rate.	%
	Primary/secondary latency	repl_lag	Data synchronization latency between the primary and secondary nodes of the instance. Note The heartbeat interval between replica set nodes is 2 seconds. Therefore, a repl_lag value between -2 and 2 is normal for replica set instances, and for shard and ConfigServer nodes of sharded cluster instances. A negative repl_lag value for a secondary node does not mean that the node is ahead of the primary node. To get the latest replication latency status of a replica set, run rs.printSecondaryReplicationInfo() on the primary node.	s
Sharded cluster instance	Total operation QPS of the shard component in a sharded cluster	insert_primary	Number of insert operations on the primary node.	count
		query_primary	Number of query operations on the primary node.	count
		update_primary	Number of update operations on the primary node.	count
		delete_primary	Number of delete operations on the primary node.	count
		getmore_primary	Number of read operations on the primary node.	count
		command_primary	Number of protocol command operations on the primary node.	count
		insert_secondary	Number of insert operations on the secondary node.	count
		query_secondary	Number of query operations on the secondary node.	count
		insert_hidden	Number of insert operations on the hidden node.	count
		query_hidden	Number of query operations on the hidden node.	count
		update_hidden	Number of update operations on the hidden node.	count
		delete_hidden	Number of delete operations on the hidden node.	count
		getmore_hidden	Number of read operations on the hidden node.	count
		command_hidden	Number of protocol command operations on the hidden node.	count
	Total operation QPS of the Mongos component in a sharded cluster	insert	Number of insert operations.	count
		query	Number of query operations.	count
		update	Number of update operations.	count
		delete	Number of delete operations.	count
		getmore	Number of read operations.	count
		command	Number of protocol command operations.	count
	moveChunk	donorCount	The number of times the current node acts as a source for moveChunk or moveRange.	count
	moveChunk	recipientCount	The number of times the current node receives chunks as the target shard.	count

Performance trends

Note

The supported metrics vary by instance type. For accurate information, see the console.

Supported instances	Metric	Metric and description
Standalone instance Replica set instance Sharded cluster instance	CPU usage	mongodb.cpu_usage: The CPU usage of the instance.
	Memory usage	mongodb.mem_usage: The memory usage of the instance.
	Disk space usage	Performance trend of instance disk space, including the following: mongodb.detailed_space_usage.ins_size: Total used space. mongodb.detailed_space_usage.data_size: Used data disk space. mongodb.detailed_space_usage.log_size: Used log disk space.
	cursors	Performance trend of instance cursor count, including the following: mongodb.metrics.cursor.timedOut: Number of cursor timeouts. mongodb.metrics.cursor.open.total: Number of currently open cursors.
	WiredTiger request queue	Performance trend of the number of read/write requests and remaining available concurrent operations, including the following: mongodb.wiredTiger.write_concurrent_trans_out: Number of concurrent write requests. mongodb.wiredTiger.read_concurrent_trans_out: Number of concurrent read requests. mongodb.wiredTiger.write_concurrent_trans_available: Number of available concurrent write operations. mongodb.wiredTiger.read_concurrent_trans_available: Number of available concurrent read operations. Note Supported only for Standard Edition replica set instances.
	WiredTiger	Performance trend of instance WiredTiger engine cache layer metrics, including the following: mongodb.wiredTiger.cache.pages.read.into.cache: Amount of data read into the cache. mongodb.wiredTiger.cache.pages.written.from.cache: Amount of data written from the cache. mongodb.wiredTiger.cache.maximum.bytes.configured: Maximum cache size. Note Supported only for Standard Edition replica set instances.
Standalone instance Replica set instance Sharded cluster instance Serverless instance	Disk usage	mongodb.disk_usage: MongoDB disk usage.
	Operation QPS	Performance trend of instance operation QPS, including the following: mongodb.opcounters.insert: Number of insert operations. mongodb.opcounters.query: Number of query operations. mongodb.opcounters.update: Number of update operations. mongodb.opcounters.delete: Number of delete operations. mongodb.opcounters.getmore: Number of read operations. mongodb.opcounters.command: Number of protocol command operations.
	Connections	mongodb.connections.current: Total current connections of the instance.
	Network traffic	Performance trend of instance network traffic, including the following: mongodb.network.bytesIn: Inbound traffic. mongodb.network.bytesOut: Outbound traffic. mongodb.network.numRequests: Number of requests processed.
Replica set instance Sharded cluster instance	IOPS usage	Performance trend of IOPS usage, including the following: mongodb.iops.data_iops: Number of read and write operations on the data disk. mongodb.iops.log_iops: Number of read and write operations on the log disk.
Replica set instance Sharded cluster instance	IOPS usage rate	mongodb.iops_usage: IOPS usage rate. Note Replica set instances and sharded cluster instances that use cloud disks and run MongoDB 4.2 do not support viewing IOPS usage and IOPS usage rate.
Replica set instance	GlobalLock	Performance trend of instance global lock, including the following: mongodb.globalLock.currentQueue.total: Total length of the global lock queue. mongodb.globalLock.currentQueue.writers: Total length of the global write lock queue. mongodb.globalLock.currentQueue.readers: Total length of the global read lock queue.