MongoDB operations

Install

emisar pack install fetches this pack, re-validates it, and verifies its content hash against the --hash below — the exact bytes this page was rendered against, so a tampered copy is rejected — before copying it into the runner's packs dir. The command reloads a running daemon itself; no manual restart.

sudo emisar pack install mongodb --hash sha256:7c737c709bc7d854c94f7152307a55d64bda5dca033cca12ce4caa70dcf2c097

• mongo.balancer_status exec low

  sh.getBalancerState()

  Show whether the balancer is enabled + currently running.

  View source on GitHub
• mongo.build_info exec low

  buildInfo

  Show server version + build flags.

  View source on GitHub
• mongo.collection_list exec low

  db.getCollectionNames()

  List collections in one database.

  View source on GitHub
• mongo.collection_stats exec low

  db.<coll>.stats()

  Show per-collection totals — count, size, storage, indexes.

  View source on GitHub
• mongo.compact_collection exec high

  db.runCommand({compact:"<coll>"})

  Compact one collection on the connected node. Reclaims disk for WiredTiger after large deletes. BLOCKS reads/writes on the collection during compaction. Run during a low-traffic window; prefer running on a secondary first.

  View source on GitHub
• mongo.concurrent_transactions exec low

  Read/write tickets (concurrency saturation)

  Show read/write ticket pools — out vs available. Queued/exhausted tickets are the classic sign of storage-engine overload. Version-tolerant: reads queues.execution on MongoDB 8.0+, else wiredTiger.concurrentTransactions (<= 7.0).

  View source on GitHub
• mongo.connection_stats exec low

  Incoming connection saturation (serverStatus.connections)

  Show incoming connection counts — current, available, active, totalCreated. Approaching the available limit means new clients will be refused. Distinct from connections (connPoolStats), which is the outgoing pool.

  View source on GitHub
• mongo.connections exec low

  connPoolStats

  Show connection pool stats — totals, active, available, by host.

  View source on GitHub
• mongo.current_op exec low

  db.currentOp()

  List in-flight operations. The canonical "what is the server doing right now?" check.

  View source on GitHub
• mongo.cursor_stats exec low

  Cursor saturation / timed-out cursors (metrics.cursor)

  Show cursor counts — open.total, open.noTimeout, open.pinned, timedOut, totalOpened. A growing timedOut count usually means an application is leaking cursors.

  View source on GitHub
• mongo.db_list exec low

  listDatabases

  List all databases with size + empty flag.

  View source on GitHub
• mongo.db_stats exec low

  db.stats()

  Show database-level totals — collections, indexes, data size, storage size.

  View source on GitHub
• mongo.default_rw_concern exec low

  Default read/write concern (getDefaultRWConcern)

  Show cluster default read and write concern (e.g. w:majority) and its source. The durability/consistency config for the replica set — a weakened default write concern is a common cause of surprising data loss on failover.

  View source on GitHub
• mongo.drop_index exec high

  db.<coll>.dropIndex("<name>")

  Drop one index from a collection. Use to remove a hot or unused index discovered via index_stats. Queries that relied on the index degrade to COLLSCAN until rebuilt or replaced.

  View source on GitHub
• mongo.election_metrics exec low

  Election / stepdown history (electionMetrics)

  Show cumulative election and stepdown counters for this member — stepUpCmd, priorityTakeover, electionTimeout, catchUpTakeover, numStepDownsCausedBy HigherTerm, numCatchUps. Use to see how often the set has been re-electing.

  View source on GitHub
• mongo.explain_query exec low

  explain a find()

  Show the execution plan for `find(filter)` on one collection at `executionStats` verbosity.

  View source on GitHub
• mongo.get_parameter exec low

  getParameter '*'

  List all server parameters (read-only view of the current config).

  View source on GitHub
• mongo.global_lock exec low

  Global lock queue / active clients (globalLock)

  Show global lock contention — currentQueue (total/readers/writers) waiting on the lock, and activeClients (total/readers/writers). A growing queue points to lock contention or an overloaded server.

  View source on GitHub
• mongo.host_info exec low

  hostInfo

  Show host CPU, memory, NUMA layout, OS.

  View source on GitHub
• mongo.index_builds exec low

  In-progress index builds (with progress)

  List active index-build operations with progress (done/total), via $currentOp. The canonical "is an index build stuck / how far along is it" check across the deployment.

  View source on GitHub
• mongo.index_stats exec low

  $indexStats aggregation

  Show per-index access counts since server start. Zeros usually mean unused indexes.

  View source on GitHub
• mongo.kill_op exec high

  db.killOp(opid)

  Kills one in-flight operation by opid.

  View source on GitHub
• mongo.long_running_ops exec low

  Long-running active ops (currentOp, secs_running >= N)

  List active operations that have been running at least N seconds — the canonical hunt for a hung or blocked op. Filters currentOp by secs_running.

  View source on GitHub
• mongo.oplog_size exec low

  Oplog size + window

  Show oplog size + first/last timestamps + estimated time window. The canonical "how far can a secondary fall behind?" check.

  View source on GitHub
• mongo.profile_slow_queries exec low

  Read slow ops from the profiler (system.profile)

  Read the database profiler collection (system.profile) for the slowest recent ops over a millis threshold, newest first. Requires profiling to be enabled on the database already (see profiler_status); does not change it.

  View source on GitHub
• mongo.profiler_status exec low

  db.getProfilingStatus()

  Show profiler level + slow-op threshold for one database.

  View source on GitHub
• mongo.replication_info exec low

  Oplog time window (db.getReplicationInfo)

  Show oplog time window — logSizeMB, usedMB, timeDiff / timeDiffHours, tFirst, tLast. How much history the oplog retains, which bounds how long a secondary can be down before it needs a full resync. Distinct from oplog size.

  View source on GitHub
• mongo.replset_config exec low

  rs.conf()

  Show replica set configuration — members, votes, priorities, settings.

  View source on GitHub
• mongo.replset_lag exec low

  Replication lag (secs behind primary)

  Show per-member seconds behind the primary, computed from rs.status() optimeDate (with state, health, sync source, ping). The canonical replica-set lag check.

  View source on GitHub
• mongo.replset_status exec low

  rs.status()

  Show replica set member health, lag, last applied optime.

  View source on GitHub
• mongo.replset_stepdown exec critical

  rs.stepDown(<seconds>)

  Force the current primary to step down. Replica set elects a new primary; ~5–15s of write unavailability is typical. Use during planned failover when one secondary is known healthier.

  View source on GitHub
• mongo.server_status exec low

  db.serverStatus()

  Show top-level server metrics: connections, ops counters, memory, cluster role.

  View source on GitHub
• mongo.shard_status exec low

  sh.status()

  Show sharded cluster summary — shards, databases, chunk distribution.

  View source on GitHub
• mongo.top exec low

  db.adminCommand({top:1})

  Show per-collection time spent in reads/writes/commands. Mongo "top" for query traffic.

  View source on GitHub
• mongo.wiredtiger_cache exec low

  WiredTiger cache pressure (serverStatus.wiredTiger.cache)

  Show WiredTiger cache pressure — bytes currently in cache vs maximum configured, tracked dirty bytes, pages evicted by application threads, and pages read into cache. Application-thread eviction and a full dirty cache indicate memory pressure.

  View source on GitHub