# Error Codes and Troubleshooting Benchmark Metrics > Depth-first rabbithole dossier for Error Codes and Troubleshooting Benchmark Metrics; source-anchored research pack. Parent: [Error Codes and Troubleshooting](https://llms-explorer.com/tree/error-codes-and-troubleshooting/) · 3 facets · 21 facts · page: https://llms-explorer.com/tree/error-codes-and-troubleshooting-benchmark-metrics/ ## How it works - [low] The `metrics.connectionAcquisitionTimeouts` counter tracks the total number of operations that failed because of server connection acquisition time out errors. Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` - [low] The `metrics.connectionFailures` counter tracks the total number of operations that completed server-side but did not send their response to the client because the connection between the client and server failed or disconnected. (verified as of 2026-10-15) Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` - [low] The `metrics.replication.source.oplogQueries` counter tracks the total number of oplog query processes created, incrementing when connection errors, timeouts, network operations occur, or when MongoDB selects a new replication source. Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` - [low] The `metrics.queryStats.maxEstimatedScanBytesExceeded` counter tracks the number of queries that exceeded the `maxEstimatedScanBytes` threshold but ran anyway because a `$natural` hint was used. (verified as of 2026-10-15) Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` - [low] The `metrics.queryStats.keyStoreFailures` counter tracks the number of times the MongoDB process failed to store a new query stats key, generally due to the `$queryStats` virtual collection running out of space. Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` - [low] The `metrics.queryStats.tokenizationFailures` counter tracks the number of times the MongoDB process failed to compute a one-way tokenized query stats key when `$queryStats` was called with the `transformIdentifiers` option. Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` - [low] The `metrics.writeConflicts.current` counter tracks the number of operations currently retrying because of write conflicts. (verified as of 2026-10-15) Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` ## Problems, failure modes and limitations - [low] The `metrics.changeStreams.error.fatal` counter tracks the number of times a change stream cursor encountered a fatal, non-resumable error, such as when a pipeline stage removes the `_id` field from change stream events. (verified as of 2026-10-15) Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` - [low] The `metrics.writeConflicts.retryLimitExceeded` counter tracks the total number of operations that returned the `WriteConflictRetryLimitExceeded` error after exceeding the adaptive write conflict retry limit. (verified as of 2026-10-15) Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` - [low] The `metrics.writeConcern.unsatisfiable` counter tracks the number of times a non-`clientSupplied` write concern returned the `UnsatisfiableWriteConcern` error code. Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` - [low] The `metrics.changeStreams.error.resumePointUnavailable` counter tracks the number of times a change stream cursor failed to resume because the requested resume point is no longer available in the oplog. (verified as of 2026-10-15) Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` - [low] The `metrics.changeStreams.error.stateChange` counter tracks the number of times a replica set state change, such as a primary stepping down, interrupted a change stream cursor. (verified as of 2026-10-15) Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` - [low] The `metrics.changeStreams.error.retriable.other` counter tracks the number of retriable change stream errors not covered by another `metrics.changeStreams.error.retriable` counter. (verified as of 2026-10-15) Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` - [low] The `metrics.changeStreams.error.nonRetriable.other` counter tracks the number of non-retriable change stream errors not covered by another counter under `metrics.changeStreams.error.nonRetriable`. (verified as of 2026-10-15) Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` - [low] The `metrics.cursors.timedOut` counter tracks the total number of cursors that have timed out since the server process started, where a large or regularly growing number may indicate an application error. Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` ## Facts and statements - [low] The `metrics.queryStats.maxEstimatedScanBytesRejected` counter tracks the number of queries that the server rejected for exceeding the threshold set by the `maxEstimatedScanBytes` parameter. (verified as of 2026-10-15) Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` - [low] The `metrics.replication.source.operationsRead` counter tracks the total number of operations read from the replication source. Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` - [low] The `metrics.queryStats.evictions` counter tracks the number of queries that the `$queryStats` virtual collection has evicted due to space constraints. Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` - [low] The `metrics.queryStats.rateLimited` counter tracks the number of times that query stats were not recorded for a query due to rate limiting. Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` - [low] The `metrics.stateChange.operationsStopped` counter tracks the total number of operations stopped during the `mongod` instance's state change. Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` - [low] The `metrics.stateChange.operationsRunning` counter tracks the total number of operations that remained running during the `mongod` instance's state change. Sources: https://www.mongodb.com/docs/manual/reference/command/serverStatus.md — source: `~/.global-ai-hub/research/.pipeline/mongodb-2026-10-14/frb/error-codes-and-troubleshooting-benchmark-metrics-7f085be1dd/rabbithole-synthesis.md#troubleshooting` ## Related concepts - Troubleshooting — is a part of Error Codes and Troubleshooting Benchmark Metrics - Metrics — is a part of Error Codes and Troubleshooting Benchmark Metrics - Error — is a part of Error Codes and Troubleshooting Benchmark Metrics - and — is a part of Error Codes and Troubleshooting Benchmark Metrics