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Metrics Reference for mongot

The mongot process exposes Prometheus metrics that describe its runtime health and performance across core areas of operation. This reference page describes key metrics that are relevant to day-to-day monitoring and troubleshooting. For the complete metric set, scrape the mongot Prometheus metrics endpoint at http://<mongot-host>:9946/metrics.

Ver métricas

To view the raw metrics that mongot exposes, send an HTTP GET request to the following mongot Prometheus metrics endpoint:

http://<mongot-host>:9946/metrics

In this endpoint:

<mongot-host> is the hostname or IP address of the mongot process.
9946 is the default port for the metrics endpoint. To configure the metrics endpoint port, see the metrics.address setting in the mongot configuration file.
/metrics is the path for the metrics endpoint.

The /metrics endpoint returns metrics in plain Prometheus text format. To monitor mongot metrics over time, configure your Prometheus instance to scrape this endpoint.

Importante

The /metrics endpoint requires no authentication by default. For production deployments, restrict access at the network layer.

Metric Naming Conventions

mongot metric names use a consistent naming pattern:

All metric names start with the mongot_ prefix.
Metric names generally follow the pattern mongot_<area>_<measurement>[_<unit>], where:
- <area> indicates the subsystem or component the metric belongs to, such as process, jvm, replication, or index.
- <measurement> indicates what is being measured, such as cpu_usage, heap_memory, or index_size.
- <unit> (optional) indicates the unit or counter semantics for the metric. This optional suffix indicates either the unit that the metric is measured in, such as seconds, bytes, or ms, or the type of counter the metric represents, such as total, events, or operations.
  
  Observação
  Some metric name suffixes don't reflect the actual reported unit for the metric. For example, mongot_index_stats_query_latency_seconds has the suffix _seconds, but mongot reports the metric in milliseconds, as indicated by the timeUnit=milliseconds label in the metric output. To confirm the unit for each metric, check the Unit value in the metric reference tables below.

In addition to the metric name, mongot metrics can include labels (also called dimensions). Labels distinguish multiple time series that share the same base metric name. For example, a metric might use labels to identify a state, status, index type, quantile, or a specific index.

For some metrics, you must interpret the metric as the combination of the metric name and its labels, not by the metric name alone. For example, mongot_replication_mongodb_indexManagerState uses the state label to expose one series for each replication state, such as STEADY_STATE or FAILED. Exactly one of those labeled series has the value 1 at a time. Per-index metrics similarly use labels such as generationId_logString and indexId_logString to distinguish one index from another.

For distribution metrics, the suffix of the metric name indicates the Prometheus series type:

Histograms expose _bucket, _count, _sum, and _max.
Summaries expose _count, _sum, and _max. Some summaries also include quantile labels such as {quantile="0.5"}.

Common Metric Labels

The following table describes common labels that appear in mongot metrics.

Label Name	Metric Scope	Valores possíveis
`name`	All executor pools	`executorMetrics`
`Scope`	Cross-cutting	`jvm`, `replication` , `lucene`
`generationId_logString`, `indexId_logString`	Most `mongot_index_stats_*` series	Internal opaque Ids (the per-index identifier that the logs use)
`indexFeatureVersion`	Many index metrics	`3`, `5`, `6` (the on-disk index format)
`indexType`	Indexing and initial-sync metrics	`search`, `vector_search`, `vector_search_auto_embedding` (only when you configure Automated Embedding)
`numPartitions`	Index size and document metrics	`1` for self-managed
`timeUnit`	Latency summary metrics	`seconds`, `milliseconds` , `microseconds`
`quantile`	Summary metrics	`0.5`, `0.75`, `0.9`, `0.99`
`state`	`indexManagerState`	`STEADY_STATE`, `INITIAL_SYNC`, `INITIAL_SYNC_BACKOFF`, `INITIALIZING`, `FAILED`, `FAILED_EXCEEDED`, `SHUT_DOWN`, `STEADY_STATE_SHUT_DOWN`
`status`	`indexStatusCode`	`STEADY`, `INITIAL_SYNC`, `FAILED`, `RECOVERING_NON_TRANSIENT`, `RECOVERING_TRANSIENT`, `STALE`, `NOT_STARTED`, `DOES_NOT_EXIST`, `UNKNOWN`
`clientName`	`mongot_mongoClient_connectionPool_*`	`mongot steady state sync`, `mongot initial sync and session refresh`, `mongot metadata service`, `mongot periodic optime fetcher`, `mongot database metadata resolver`, `mongot server info resolver`, `mongot Lease Manager mongo client`, `mongot AutoEmbedding Materialized View Writer` (only when Automated Embedding is enabled)

Key Metric Groups

Process and JVM Metrics

Use process and JVM metrics to confirm that mongot is running normally and to identify heap or garbage collection pressure.

Processo

Métrica	Tipo	unidade	Descrição
`mongot_process_uptime_seconds`	Medidor	Segundos	The uptime of the Java Virtual Machine.
`mongot_process_start_time_seconds`	Medidor	unix seconds	Start time of the process since unix epoch.
`mongot_process_cpu_time_ns_total`	Contador	nanossegundos	The "cpu time" used by the Java Virtual Machine process. Use `rate()` for instantaneous CPU consumption.
`mongot_process_cpu_usage`	Medidor	0-1	The "recent cpu usage" for the Java Virtual Machine process.

JVM Memory

Métrica	Tipo	unidade	Descrição
`mongot_jvm_memory_used_bytes`	Medidor	bytes	The amount of used memory. Labels: `area=heap\|nonheap`, `id=<pool>` (for example, G1 Eden Space, G1 Old Gen, G1 Survivor Space, Metaspace).
`mongot_jvm_memory_committed_bytes`	Medidor	bytes	The amount of memory committed for the Java virtual machine to use.
`mongot_jvm_memory_max_bytes`	Medidor	bytes	The maximum memory that can be used. For heap, `id="G1 Old Gen"` carries `-Xmx`.
`mongot_jvm_buffer_count_buffers`	Medidor	contar	NIO buffer pool counts. Labels: `id=direct\|mapped`.
`mongot_jvm_buffer_memory_used_bytes`	Medidor	bytes	Memory the JVM uses for NIO buffer pools.
`mongot_jvm_buffer_total_capacity_bytes`	Medidor	bytes	NIO buffer pool capacity.

JVM Garbage Collection

Métrica	Tipo	unidade	Descrição
`mongot_jvm_gc_pause_seconds`	Resumo	Segundos	Time spent in GC pause. No quantile labels. Use `mongot_jvm_gc_pause_seconds_max` for the longest recent pause.
`mongot_jvm_gc_concurrent_phase_time_seconds`	Resumo	Segundos	Time spent in concurrent GC phase.
`mongot_jvm_gc_live_data_size_bytes`	Medidor	bytes	Size of long-lived heap memory pool after reclamation. The "live heap" to watch for memory pressure.
`mongot_jvm_gc_max_data_size_bytes`	Medidor	bytes	Max size of long-lived heap memory pool.
`mongot_jvm_gc_memory_allocated_bytes_total`	Contador	bytes	Increase in young heap pool size between GCs.
`mongot_jvm_gc_memory_promoted_bytes_total`	Contador	bytes	Promotions from young into old generation.

System Metrics

Use system metrics to monitor host-level CPU, disk, memory, paging, and network conditions that can affect mongot.

CPU

Métrica	Tipo	unidade	Descrição
`mongot_system_cpu_count`	Medidor	contar	Processors available to the JVM.
`mongot_system_cpu_usage`	Medidor	0–1	Recent system CPU usage.
`mongot_system_load_average_1m`	Medidor	sem unidade	OS 1-minute load average.

Disk

Métrica	Tipo	unidade	Descrição
`mongot_system_disk_space_data_path_free_bytes`	Medidor	bytes	Free disk space on the `mongot` `dataPath` volume. Alert on this metric.
`mongot_system_disk_space_data_path_total_bytes`	Medidor	bytes	Total disk space on the `dataPath` volume. Use to compute free %.
`mongot_system_disk_space_free_bytes`, `mongot_system_disk_space_total_bytes`	Medidor	bytes	Free and total disk space across the file system (different scope than `data_path`).
`mongot_system_disk_readBytes_bytes`	Medidor	bytes	Bytes read from disk per device. Label: `name=<device>` (e.g., `/dev/vda`).
`mongot_system_disk_writeBytes_bytes`	Medidor	bytes	Bytes written per device.
`mongot_system_disk_reads_events`	Medidor	contar	Read I/O count per device. Use `rate()` for read IOPS.
`mongot_system_disk_writes_events`	Medidor	contar	Write I/O count per device.
`mongot_system_disk_currentQueueLength_tasks`	Medidor	contar	Disk queue length (I/Os in progress) per device.
`mongot_system_disk_transferTime_ms`	Medidor	Milissegundos	Time spent reading or writing per device.

Memória

Métrica	Tipo	unidade	Descrição
`mongot_system_memory_phys_total_bytes`	Medidor	bytes	Total physical memory on the host.
`mongot_system_memory_phys_available_bytes`	Medidor	bytes	Physical memory available.
`mongot_system_memory_phys_inUse_bytes`	Medidor	bytes	Physical memory in use.
`mongot_system_memory_virt_inUse_bytes`	Medidor	bytes	Total physical and virtual memory in use.
`mongot_system_memory_virt_swap_inUse_bytes`, `mongot_system_memory_virt_swap_available_bytes` , `mongot_system_memory_virt_swap_total_bytes`	Medidor	bytes	Swap state.
`mongot_system_memory_virt_swap_pagesIn_operations`, `mongot_system_memory_virt_swap_pagesOut_operations`	Medidor	contar	Swap in/out activity.
`mongot_system_memory_memoryMappings_objects`	Medidor	contar	Number of memory mappings (relevant for Lucene mmap counts).
`mongot_system_memory_pageSize_bytes`	Medidor	bytes	System page size.

Falhas na página

Métrica	Tipo	unidade	Descrição
`mongot_system_process_majorPageFaults_operations`	Medidor	contar	Major page faults. Use this metric with the storage class advisory threshold.
`mongot_system_process_minorPageFaults_operations`	Medidor	contar	Minor page faults.

Rede

Métrica	Tipo	unidade	Descrição
`mongot_system_netstat_bytesRecv_bytes`, `mongot_system_netstat_bytesSent_bytes`	Medidor	bytes	Bytes received and sent per interface (`name=eth0`).
`mongot_system_netstat_packetsRecv_events`, `mongot_system_netstat_packetsSent_events`	Medidor	contar	Packets received and sent.
`mongot_system_netstat_inErrors_events`, `mongot_system_netstat_outErrors_events`, `mongot_system_netstat_inDrops_events`, `mongot_system_netstat_collisions_events`	Medidor	contar	Error, drop, and collision counters.
`mongot_system_netstat_speed`	Medidor	bits/sec	Negotiated interface speed.

Métricas de replicação

Use replication metrics to determine whether mongot is healthy, syncing normally, and staying caught up with mongod.

Overall State

Métrica	Tipo	unidade	Descrição
`mongot_replication_manager`	Medidor	0/1	`1` when the replication manager is active.
`mongot_replication_mongodb_manager`	Medidor	0/1	`1` when the MongoDB-backed replication manager is active. Label: `type=normal`.
`mongot_replicationIndexManager_transitionState_total`	Contador	contar	State transitions. Labels: `fromState`, `toState`. Use to detect resyncs (`INITIALIZING` to `STEADY_STATE` transitions).

Session Refresher

Métrica	Tipo	unidade	Descrição
`mongot_replication_sessionRefresher_sessions`	Medidor	contar	Active sessions.
`mongot_replication_sessionRefresher_refreshes_total`	Contador	contar	Total session refreshes.
`mongot_replication_sessionRefresher_failedSessionRefreshes_total`	Contador	contar	Failed refreshes.
`mongot_replication_sessionRefresher_sessionRefreshDurations_seconds`	Resumo	Segundos	Refresh duration distribution.

Optime Updater

Métrica	Tipo	unidade	Descrição
`mongot_replicationOptimeUpdaterError_total`	Contador	contar	Optime-update errors.
`mongot_replicationOptimeUpdater_executor_*`	vários	N/A	Executor metrics for the optime updater.

Per-index Metrics

mongot emits the following metrics per index and includes generationId_logString and indexId_logString labels to identify the specific index. Filter by those labels to inspect a specific index, or aggregate across labels to understand fleet-wide behavior.

Index Status and Size

Métrica	Tipo	unidade	Descrição
`mongot_index_stats_indexStatusCode`	Medidor	0/1	Per-index status. One-hot encoded across the `status` label values: `STEADY`, `INITIAL_SYNC`, `FAILED`, `RECOVERING_NON_TRANSIENT`, `RECOVERING_TRANSIENT`, `STALE`, `NOT_STARTED`, `DOES_NOT_EXIST`, `UNKNOWN`.
`mongot_index_stats_indexFeatureVersion`	Medidor	número	On-disk index format version. For example, `3`.
`mongot_index_stats_indexSizeBytes`	Medidor	bytes	Total on-disk size of the index.
`mongot_index_stats_largestIndexFileSizeBytes`	Medidor	bytes	Largest single file in the index.
`mongot_index_stats_numFilesInIndex`	Medidor	contar	Number of Lucene segment files.
`mongot_index_stats_numLuceneDocs`	Medidor	contar	Lucene documents in the index.
`mongot_index_stats_numLuceneMaxDocs`	Medidor	contar	Maximum Lucene document ID (includes deleted-not-merged).
`mongot_index_stats_numLuceneFields`	Medidor	contar	Number of indexed Lucene fields.
`mongot_index_stats_segment_count`	Medidor	contar	Number of Lucene segments.
`mongot_index_stats_requiredMemoryBytes`	Medidor	bytes	Estimated required memory for the index.

Indexing Metrics

Métrica	Tipo	unidade	Descrição
`mongot_index_stats_indexing_replicationLagMs`	Medidor	Milissegundos	Replication lag per index, in milliseconds. The unit is in the metric name (`Ms`). Do not divide by 1000 in PromQL unless you want to convert to seconds.
`mongot_index_stats_indexing_replicationOpTime`	Medidor	BSON Timestamp	Last applied replication optime (numeric encoding).
`mongot_index_stats_indexing_maxPossibleReplicationOpTime`	Medidor	BSON Timestamp	Cap on advance, set by `mongod` tip.
`mongot_index_stats_indexing_insert_total`, `mongot_index_stats_indexing_update_total` , `mongot_index_stats_indexing_delete_total`	Contador	contar	Indexing operation counts. Label: `indexType=search`.
`mongot_index_stats_indexing_totalBytesProcessed_total`	Contador	bytes	Total bytes processed by indexing.
`mongot_index_stats_indexing_vectorFieldsIndexed_total`	Contador	contar	Vector fields indexed.
`mongot_index_stats_indexing_commitDurations_seconds`	Resumo	seconds (`timeUnit=milliseconds`)	Per-index commit durations.
`mongot_index_stats_indexing_indexingBatchDurations_seconds`	Resumo	Segundos	Batch duration distribution.
`mongot_index_stats_indexing_largeChangeStreamEvents_total`	Contador	contar	Oversized change-stream events. Label: `threshold=10MiB\|12MiB\|14MiB\|15MiB`.
`mongot_index_stats_indexing_invalidGeometryField_total`	Contador	contar	Documents rejected for invalid geometry.
`mongot_index_stats_indexing_sortableStringTruncated_total`	Contador	contar	Truncated sortable strings.
`mongot_index_stats_indexing_initialSyncExceptions_total`	Contador	contar	Exceptions during initial sync.
`mongot_index_stats_indexing_steadyStateExceptions_total`	Contador	contar	Steady-state exceptions.
`mongot_index_stats_indexing_consecutiveInitialSyncResyncExceptions`	Medidor	contar	Consecutive initial-sync resync exceptions for this index.

Métricas de query

Métrica	Tipo	unidade	Descrição
`mongot_index_stats_query_totalQueries_total`	Contador	contar	Total queries issued against the index.
`mongot_index_stats_query_totalHitsCount_total`	Contador	contar	Total hits returned.
`mongot_index_stats_query_failedQueries_total`	Contador	contar	Queries that failed.
`mongot_index_stats_query_internallyFailedQueries_total`, `mongot_index_stats_query_invalidQueries_total`, `mongot_index_stats_query_npeQueries_total`, `mongot_index_stats_query_lenientFailures_total`	Contador	contar	Specific failure-class counters.
`mongot_index_stats_query_searchResultBatchLatencies_seconds`	Resumo	seconds (`timeUnit=milliseconds`)	Search batch latency. This is the headline query-latency metric.
`mongot_index_stats_query_luceneTopDocsSearchLatencies_seconds`	Resumo	seconds (`timeUnit=milliseconds`)	Latency inside Lucene's TopDocs search. Use this metric to distinguish Lucene-internal latency from total latency.
`mongot_index_stats_query_vectorResultLatencies_seconds`	Resumo	seconds (`timeUnit=milliseconds`)	Vector search result latency.
`mongot_index_stats_query_vectorSearchInitialTopDocsLatencyTimer_seconds`, `mongot_index_stats_query_vectorSearchGetMoreTopDocsLatencyTimer_seconds`	Resumo	seconds (`timeUnit=milliseconds`)	Vector search latency phases.
`mongot_index_stats_query_tokenFacetsStateRefreshLatency_seconds`	Resumo	seconds (`timeUnit=milliseconds`)	Facets state-refresh latency.
`mongot_index_stats_query_batchDataSize`, `mongot_index_stats_query_batchDocumentCount`	Resumo	bytes / count	Per-batch payload size and document count.
`mongot_index_stats_query_limitPerQuery`	histogram	count (`le=10\|50\|100\|200\|500\|1000\|+Inf`)	Distribution of `$search` and `$vectorSearch` limits.
`mongot_index_stats_query_numCandidatesPerQuery`	histogram	contar	Vector candidates per query, bucketed by quantization.
`mongot_index_stats_query_getMoreCommandCalls_total`, `mongot_index_stats_query_getMoreCommandCallsPerQuery`	counter / summary	contar	`getMore` call counts.
`mongot_index_stats_query_batchWithTies_total`	Contador	contar	Result batches with score ties.
`mongot_index_stats_query_benefitFromIndexSortCount_total`	Contador	contar	Queries that benefited from index sort optimization.
`mongot_index_stats_query_extractableLimitQueries_total`, `mongot_index_stats_query_extractableLimitSecondBatchQueries_total`	Contador	contar	Limit-extraction optimizations triggered.
`mongot_index_stats_query_phantomSearcherCleanupCount_total`	Contador	contar	Phantom-searcher cleanups.
`mongot_index_stats_query_orphanedDeletedDocsRatio`	Resumo	ratio	Deleted-document ratio in returned results.
`mongot_index_stats_query_noProgressBatches_total`	Contador	contar	Batches that made no forward progress.
`mongot_index_stats_query_vectorCommandCalls_total`, `mongot_index_stats_query_vectorRescoringFailureCount_total` , `mongot_index_stats_query_vectorSearchQueriesOverSearchIndexes_total`	Contador	contar	Vector-specific counters.
`mongot_index_stats_query_feature_total`	Contador	contar	Per-query-feature usage. Label: `name=<feature>`. For example, `compound`, `text`, `phrase`, `near`, `vectorSearch`, `knnBeta`, `autoEmbedding` (only when Automated Embedding is enabled).
`mongot_index_stats_query_failedExplainQueryAggregate_total`	Contador	contar	Failed `$explain` aggregates.

Per-index Replication Breakdown

Métrica	Tipo	unidade	Descrição
`mongot_replication_mongodb_indexManagerState`	Medidor	0/1	The canonical replication-state signal. `mongot` one-hot encodes this metric, meaning that exactly one `state` label is `1.0`. States: `STEADY_STATE`, `INITIAL_SYNC`, `INITIAL_SYNC_BACKOFF`, `INITIALIZING`, `FAILED`, `FAILED_EXCEEDED`, `SHUT_DOWN`, `STEADY_STATE_SHUT_DOWN`.
`mongot_index_stats_replication_steadyState_batchTotalApplicableBytes`, `mongot_index_stats_replication_steadyState_batchTotalApplicableDocuments`	Resumo	bytes / count	Steady-state batch sizes.
`mongot_index_stats_replication_steadyState_decodingBatchDurations_seconds`	Resumo	Segundos	Steady-state decoding duration.
`mongot_index_stats_replication_steadyState_getMoreDurations_seconds`	Resumo	Segundos	Steady-state `getMore` duration.
`mongot_index_stats_replication_initialSync_changeStream_*`	Resumo	—	Initial-sync change-stream phase metrics (mirrors steady state).
`mongot_index_stats_replication_initialSync_collScan_*`	Resumo	—	Initial-sync collection-scan phase metrics.

Lucene Refresh Latency

Métrica	Tipo	unidade	Descrição
`mongot_index_stats_luceneIndexRefresher_refreshDurations_seconds`	Resumo	seconds (`timeUnit=milliseconds`)	Lucene IndexReader refresh latency.

Command Metrics

mongot accepts the following set of named commands from mongod:

buildinfo
getMore
hello
isMaster
ismaster
killCursors
manageSearchIndex
ping
planShardedSearch
search
vectorSearch

For each command, mongot exposes the following metrics, where <name> is a placeholder for the command name:

Padrão	Tipo	Descrição
`mongot_command_<name>CommandFailure_total`	Contador	Failure count for the command.
`mongot_command_<name>CommandTotalLatency_seconds`	Resumo	End-to-end latency including serialization.
`mongot_command_<name>CommandSerializationLatency_seconds`	Resumo	Serialization latency (subset; not all commands).

Dica

Monitor Search and Vector Search Latency Across Indexes

mongot_command_searchCommandTotalLatency_seconds and mongot_command_vectorSearchCommandTotalLatency_seconds are the primary metrics to monitor for $search and $vectorSearch latency aggregates. These expose latency aggregates for all search and vectorSearch commands across all indexes.

Indexing Scheduler and Dispatcher Metrics

Use indexing scheduler and dispatcher metrics to identify backlog, saturation, and slow work in replication and indexing pipelines.

Steady-state Change-stream Pipeline

Métrica	Tipo	unidade	Descrição
`mongot_indexing_steadyStateChangeStream_batchesInProgressTotal`	Medidor	contar	Batches currently being applied. Label: `indexType=search\|vector_search\| vector_search_auto_embedding` (only when you enable Automated Embedding).
`mongot_indexing_steadyStateChangeStream_batchesInProgressTotalDurations_seconds`	Resumo	Segundos	Duration distribution for in-flight batches.
`mongot_indexing_steadyStateChangeStream_getMoreDurations_seconds`	Resumo	Segundos	`getMore` round-trip distribution.
`mongot_indexing_steadyStateChangeStream_getMoresInFlight`	Medidor	contar	`getMore` requests in flight.
`mongot_indexing_steadyStateChangeStream_getMoresScheduled`	Medidor	contar	Scheduled `getMore` requests by `indexType`.
`mongot_indexing_steadyStateChangeStream_getMoresSchedulingDurations_seconds`	Resumo	Segundos	`getMore` scheduling latency.
`mongot_indexing_steadyStateChangeStream_preprocessingBatchDurations_seconds`	Resumo	Segundos	Pre-processing duration per batch.
`mongot_indexing_steadyStateChangeStream_witnessedChangeStreamUpdates_total`	Contador	contar	Total change-stream events observed. Label: `Scope=replication`.
`mongot_indexing_steadyStateChangeStream_applicableChangeStreamUpdates_total`	Contador	contar	Events that `mongot` considered applicable.
`mongot_indexing_steadyStateChangeStream_dispatcher`	Medidor	0/1	Dispatcher status. Labels: `Scope=replication`, `client=synchronous-batch`.
`mongot_indexing_steadyStateChangeStream_skippedChangeStreamDocumentsWithoutMetadataNamespace_total`	Contador	contar	Events skipped due to missing metadata.
`mongot_indexing_steadyStateChangeStream_unexpectedBatchFailures_total`	Contador	contar	Unexpected batch failures.
`mongot_indexing_steadyStateChangeStream_rescheduledEmbeddingGetMores_total`	Contador	contar	Rescheduled embedding getMores. This metric is only available when you configure Automated Embedding.
`mongot_indexing_changeStreamModeSelector_failedSamplingAttemptsCounter_total`	Contador	contar	Failed change-stream mode sampling attempts.

Indexing Work Scheduler

Indexing work scheduler metrics monitor the queueing and execution of indexing batches.

Métrica	Tipo	unidade	Descrição
`mongot_indexingWorkScheduler_queuedBatchesTotal`, `mongot_indexingWorkScheduler_queuedEventsTotal`	Medidor	contar	Scheduler queue depth.
`mongot_indexingWorkScheduler_enqueueCalls_total`, `mongot_indexingWorkScheduler_dequeueCalls_total`	Contador	contar	Enqueue and dequeue counts.
`mongot_indexingWorkScheduler_indexingBatchDistribution`	Resumo	contar	Distribution of batch sizes. Label: `Scope=replication`.
`mongot_indexingWorkScheduler_indexingBatchDurations_seconds`	Resumo	Segundos	Batch durations.
`mongot_indexingWorkScheduler_indexingBatchSchedulingDurations_seconds`	Resumo	Segundos	Scheduling overhead.

Decoding Work Scheduler

Decoding work scheduler metrics monitor the queueing and execution of change-stream batch decoding.

Métrica	Tipo	unidade	Descrição
`mongot_decodingWorkScheduler_queuedBatchesTotal`, `mongot_decodingWorkScheduler_queuedEventsTotal`	Medidor	contar	Scheduler queue depth.
`mongot_decodingWorkScheduler_enqueueCalls_total`, `mongot_decodingWorkScheduler_dequeueCalls_total`	Contador	contar	Enqueue and dequeue counts.
`mongot_decodingWorkScheduler_decodingBatchDistribution`	Resumo	contar	Distribution of batch sizes. Label: `Scope=replication`.
`mongot_decodingWorkScheduler_decodingBatchDurations_seconds`	Resumo	Segundos	Batch durations.
`mongot_decodingWorkScheduler_decodingBatchSchedulingDurations_seconds`	Resumo	Segundos	Scheduling overhead.

Initial Sync, Lifecycle, and Config Metrics

Use these metrics to track index startup work, recovery, and catalog state.

Sincronização inicial

Observação

Some mongot metrics are phase-specific and populate only when the corresponding code path is active. For example, steady-state replication metrics, such as mongot_index_stats_indexing_replicationLagMs and the mongot_index_stats_replication_steadyState_* series, do not populate while an index is in initial sync. Conversely, initial-sync-specific metrics, such as mongot_initialsync_* and mongot_index_stats_replication_initialSync_*, are only relevant while initial sync is running or has run.

Métrica	Tipo	unidade	Descrição
`mongot_initialsync_queue_queuedSyncs`	Medidor	contar	Queued initial syncs. Label: `indexType`.
`mongot_initialsync_queue_requeuedEmbeddingInitialSyncs_total`	Contador	contar	Embedding initial syncs that were requeued. This metric is only available when you configure Automated Embedding.
`mongot_initialsync_dispatcher_inProgressSyncs`	Medidor	contar	Initial syncs currently in progress. Label: `indexType`.
`mongot_initialsync_dispatcher_queuedSyncs`	Medidor	contar	Initial syncs queued at the dispatcher.
`mongot_initialsync_dispatcher_inProgressResumedSyncs`	Medidor	contar	In-progress syncs that resumed from a checkpoint.
`mongot_initialsync_dispatcher_collectionScan`	Medidor	0/1	Active collection-scan mode. Label: `scan_type=id_order\|natural_order`.
`mongot_initialsync_dispatcher_completedSyncDuration_seconds`	Resumo	Segundos	Completed sync duration distribution.
`mongot_initialsync_dispatcher_syncDuration_seconds`	Resumo	Segundos	Ongoing sync duration.
`mongot_initialsync_dispatcher_inProgressInitialSyncDurationMin_seconds`, `mongot_initialsync_dispatcher_inProgressInitialSyncDurationMax_seconds` , `mongot_initialsync_dispatcher_inProgressInitialSyncDurationSum_seconds`	Medidor	Segundos	Min, max, and sum of in-progress initial sync durations.
`mongot_initialsync_dispatcher_unreadableDroppedIndexes_total`	Contador	contar	Dropped because their on-disk segments could not be read.
`mongot_initialsync_dispatcher_unreadableIndexRecoveries_total`	Contador	contar	Recovered after unreadable segments. Label: `unreadableIndexCause=corruptIndex\|incompatibleCodec\| incompatibleIndexFormat`.

Ciclo de vida

Métrica	Tipo	unidade	Descrição
`mongot_lifecycle_indexesInInitializedState`	Medidor	contar	Indexes currently in the initialized state.
`mongot_lifecycle_indexInitializationDuration_seconds`	Resumo	Segundos	Initialization durations.
`mongot_lifecycle_failedDownloadIndexes_total`	Contador	contar	Index downloads that failed.
`mongot_lifecycle_failedDropIndexes_total`	Contador	contar	Index drops that failed.
`mongot_lifecycle_failedInitializationIndexes_total`	Contador	contar	Index initializations that failed.

Config State

Métrica	Tipo	unidade	Descrição
`mongot_configState_indexesInCatalog`	Medidor	contar	Indexes currently in the catalog. Labels: `Scope=replication`, `indexFormatVersion`.
`mongot_configState_indexesPhasingOut`	Medidor	contar	Indexes being phased out.
`mongot_configState_stagedIndexes`	Medidor	contar	Staged but not yet active indexes.
`mongot_configState_indexesInCatalogFeatureVersionFour`, `mongot_configState_indexesPhasingOutFeatureVersionFour` , `mongot_configState_stagedIndexesFeatureVersionFour`	Medidor	contar	Feature-version-4-specific equivalents.

Cursors and Index Factory

Use these metrics to monitor open cursor state and to detect indexes that mongot dropped or recovered because their on-disk segments were unreadable.

Métrica	Tipo	unidade	Descrição
`mongot_cursorManager_trackedCursors`	Medidor	contar	Currently tracked open cursors.
`mongot_indexFactory_unreadableDroppedIndexes_total`	Contador	contar	Indexes dropped because their segments were unreadable.
`mongot_indexFactory_unreadableIndexRecoveries_total`	Contador	contar	Recoveries after unreadable segments. Label: `unreadableIndexCause`.

Lucene Merge

Use these metrics to monitor Lucene segment merge activity, including the number and size of merges in progress, merge input and output sizes, merge durations, and merges discarded by the disk-utilization merge policy.

Métrica	Tipo	unidade	Descrição
`mongot_mergeScheduler_currentlyRunningMerges`	Medidor	contar	Active merges. Label: `Scope=lucene`.
`mongot_mergeScheduler_currentlyMergingDocs`	Medidor	contar	Documents currently being merged.
`mongot_mergeScheduler_numMerges_total`	Contador	contar	Total merges executed since startup.
`mongot_mergeScheduler_numSegmentsMerged_total`	Contador	contar	Segments folded by merges.
`mongot_mergeScheduler_mergeSize`	Resumo	bytes	Distribution of merge input sizes.
`mongot_mergeScheduler_mergeResultSize`	Resumo	bytes	Distribution of merge output sizes.
`mongot_mergeScheduler_mergedDocs`	Resumo	contar	Documents-per-merge distribution.
`mongot_mergeScheduler_mergeTime_seconds`	Resumo	Segundos	Merge duration distribution.
`mongot_diskUtilizationAwarenessMergePolicy_discardedMerge_total`	Contador	contar	Merges discarded by the disk-utilization-aware policy.

MongoDB Client Connection Pool Metrics

mongot opens multiple named connection pools to mongod, and labels each pool with a clientName label that identifies the role of each pool. The following table lists possible clientName label values and their corresponding role:

clientName	Propósito
`mongot steady state sync`	Steady-state change-stream replication.
`mongot initial sync and session refresh`	Initial sync and session refresh. The `appName` seen in `mongod` `currentOp`.
`mongot metadata service`	Internal metadata service.
`mongot periodic optime fetcher`	Optime polling.
`mongot database metadata resolver`	Database metadata lookups.
`mongot server info resolver`	Server-info lookups.
`mongot Lease Manager mongo client`	Lease manager.
`mongot AutoEmbedding Materialized View Writer`	Automated embedding writes. This connection pool only appears when you configure Automated Embedding.

The following table lists the available metrics for mongot connection pools:

Métrica	Tipo	unidade	Descrição
`mongot_mongoClient_connectionPool_connections`	Medidor	contar	Currently open connections in the pool.
`mongot_mongoClient_connectionPool_connectionsCheckedOut`	Medidor	contar	Connections currently checked out.
`mongot_mongoClient_connectionPool_maxSize`	Medidor	contar	Configured max pool size.
`mongot_mongoClient_connectionPool_minSize`	Medidor	contar	Configured min pool size.
`mongot_mongoClientBuilder_successfulOpenSSLDynamicLinking_total`	Contador	contar	Successful native OpenSSL link attempts.
`mongot_mongoClientBuilder_failedOpenSSLDynamicLinking_total`	Contador	contar	Failed native OpenSSL link attempts.

Sinônimos

Use these metrics to monitor synonym synchronization activity, including collection scans, scan and sync durations, queue depth, and exceptions encountered during synonym sync.

Métrica	Tipo	unidade	Descrição
`mongot_synonymSync_collScans_total`	Contador	contar	Total collection scans performed for synonyms.
`mongot_synonymSync_collScansTriggeredByChangeStream_total`	Contador	contar	Synonym scans triggered by change-stream events.
`mongot_synonymSync_collScanDurations_seconds`	Resumo	Segundos	Scan duration distribution.
`mongot_synonymSync_syncDurations_seconds`	Resumo	Segundos	Sync duration distribution.
`mongot_synonymSync_queueDepth`	Medidor	contar	Current synonym sync queue depth.
`mongot_synonymSync_exceptions_total`	Contador	contar	Synonym sync exceptions.

Executor Pools

Use these metrics to monitor the named executor pools that mongot uses to run background work. Each pool exposes the same set of sub-metrics, prefixed with the pool name, so you can track thread activity, pool sizing, queue depth, task throughput, and per-task execution time across all pools.

The following table lists the sub-metrics that every executor pool exposes, where <pool> is the pool name prefix. All executor-pool sub-metrics carry the label name="executorMetrics".

Sub-Metric Suffix	Tipo	Descrição
`<pool>_active_threads`	Medidor	Threads currently executing tasks.
`<pool>_pool_core_threads`, `<pool>_pool_max_threads` , `<pool>_pool_size_threads`	Medidor	Pool sizing.
`<pool>_queued_tasks`	Medidor	Tasks waiting for a thread — the saturation signal.
`<pool>_queue_remaining_tasks`	Medidor	Remaining queue capacity.
`<pool>_completed_tasks_total`	Contador	Tasks completed since startup.
`<pool>_idle_seconds`	Resumo	Time threads spent idle between tasks.
`<pool>_seconds`	Resumo	Per-task execution time.
`<pool>_scheduled_once_total`, `<pool>_scheduled_repetitively_total`	Contador	Scheduled task counts (for scheduling pools).

The following table lists the prefixes for all available named executor pools and their respective purposes:

Executor Pool Prefix	What it runs
`mongot_blobstore_lifecycle_executor`	Blob-store lifecycle work.
`mongot_blocking_server_worker_executor`	Blocking gRPC server worker threads.
`mongot_change_stream_mode_selector_executor`	Change-stream mode selection.
`mongot_change_stream_sync_dispatcher_executor`	Change-stream sync dispatching (one of the busiest in steady state).
`mongot_config_monitor_executor`	Config-monitor polling.
`mongot_decoding_executor`	Decoding pipeline workers.
`mongot_disk_monitor_executor`	Disk-monitor polling.
`mongot_grpc_health_check_executor`	gRPC health check timer.
`mongot_idle_cursor_killer_executor`	Idle cursor reaping.
`mongot_index_commit_executor`	Index commit operations.
`mongot_index_lifecycle_executor`	Per-index lifecycle work.
`mongot_index_refresh_executor`	Lucene IndexReader refreshes.
`mongot_indexing_work_executor`	Indexing pipeline workers (the busiest indexing pool in steady state).
`mongot_indexing_lifecycle_executor`	Indexing-lifecycle work.
`mongot_indexing_auto_embedding_executor`	Automated-embedding indexing path. This executor pool only appears when you configure Automated Embedding.
`mongot_init_lifecycle_executor`	Init-time lifecycle work.
`mongot_mat_view_commit_executor`, `mongot_mat_view_leader_heartbeat_executor`, `mongot_mat_view_optime_updater_executor`, `mongot_mat_view_status_refresh_executor`, `mongot_materialized_view_lifecycle_executor`	Materialized-view tracking and lifecycle. These metrics are only available when Automated Embedding or other materialized-view-backed features are configured.
`mongot_replicationOptimeUpdater_executor`	Optime updater (background).
`mongot_session_refresh_executor`	Session refresher.
`mongot_system_metrics_updater_executor`	System metrics updater.

Dica

Watch Saturation Across All Executor Pools

To monitor saturation across all executor pools, run the following PromQL query:

max by (pool) (
  label_replace(
    {__name__=~"mongot_.+_executor_queued_tasks"},
    "pool", "$1", "__name__", "mongot_(.+)_executor_queued_tasks"
  )
)

This query returns the queued-task count for each executor pool.

Prometheus Server Self-Metrics

The following metric is available for the embedded Prometheus server in mongot:

Métrica	Tipo	unidade	Descrição
`mongot_prometheus_server_scraping_timer_seconds`	Resumo	seconds (`timeUnit=milliseconds`)	How long `mongot` takes to assemble a `/metrics` response. Sustained growth here means metric exposition itself is slowing down.

Configuration-Specific Metrics

The following metric families appear in the /metrics output only when you enable specific features.

Metric Family	Descrição	Availability in Self-Managed `mongot`
`mongot_embedding`	Metrics related to Automated Embedding. For example, `mongot_initialsync_queue_requeuedEmbeddingInitialSyncs_total`, `mongot_materialized_view_lifecycle_executor`, and connection-pool entries with `clientName="mongot AutoEmbedding Materialized View Writer"`.	Appear only when you configure Automated Embedding.
`mongot_mongot_ftdc_executor_failure_total`	Failure count for the FTDC executor.	Appears only when you enable the `ftdcExecutorMetricsToPrometheus` feature flag.

PromQL Examples

Most latency metrics in this catalog are summaries, not histograms, so use their published quantile labels directly when they exist. A smaller number of metrics, such as mongot_index_stats_query_limitPerQuery and mongot_index_stats_query_numCandidatesPerQuery, are histograms and expose _bucket series.

# Replication state
max by (state) (mongot_replication_mongodb_indexManagerState == 1)
# Maximum replication lag across all indexes, converted to seconds
max(mongot_index_stats_indexing_replicationLagMs) / 1000
# Index count by status
count by (status) (mongot_index_stats_indexStatusCode == 1)
# Search query p99 latency across all indexes
max(mongot_index_stats_query_searchResultBatchLatencies_seconds{quantile="0.99"})
# Worst recent GC pause
max(mongot_jvm_gc_pause_seconds_max)
# Average GC pause over 5 minutes
rate(mongot_jvm_gc_pause_seconds_sum[5m]) / rate(mongot_jvm_gc_pause_seconds_count[5m])
# Free disk percentage on dataPath
mongot_system_disk_space_data_path_free_bytes
  / mongot_system_disk_space_data_path_total_bytes
# Major page fault rate
rate(mongot_system_process_majorPageFaults_operations[5m])
# Steady-state and initial sync exceptions over 15 minutes
sum(rate(mongot_index_stats_indexing_steadyStateExceptions_total[15m]))
sum(rate(mongot_index_stats_indexing_initialSyncExceptions_total[15m]))

Voltar

Set Up Monitoring for New Deployment

mongot Logs and FTDC