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Compatibility commands
These commands have gateway handlers but do not implement all behavior implied by their MongoDB names. Except where noted, no command-specific option changes their response.
Status and information commands
| Command | Invocation | Implemented behavior |
|---|---|---|
ping | { ping: 1 } | Returns { ok: 1 }; checks gateway responsiveness, not database health. |
buildInfo | { buildInfo: 1 } | Returns configured MongoDB-compatible version, versionArray, bits: 64, and maxBsonObjectSize. buildinfo is an alias. Use hello for the engine version. |
getCmdLineOpts | { getCmdLineOpts: 1 } | Returns an empty argv array, not the gateway's actual startup arguments. |
getLog | { getLog: "global" } | Returns empty log and totalLinesWritten: 0; does not expose server logs or implement log-name selection. |
hostInfo | { hostInfo: 1 } | Returns current time with placeholder memory, OS, and CPU fields. |
isdbgrid | { isdbgrid: 1 } | Returns isdbgrid: 1 and the configured hostname. Not a complete shard-health check. |
whatsmyuri | { whatsmyuri: 1 } | Returns only { ok: 1 }; no client URI. |
For example:
db.runCommand({ ping: 1 })
db.serverBuildInfo()getDefaultRWConcern
Run on admin:
db.adminCommand({ getDefaultRWConcern: 1 })The response always reports implicit majority read and write concerns, with wtimeout: 0. This is a fixed compatibility response, not evidence that arbitrary per-command concern options are implemented.
Other no-ops
enableSharding returns success without enabling a database-level sharding state. refreshSessions and killAllSessionsByPattern return success without refreshing or terminating sessions. Their command arguments are not used to perform those operations. See session commands for commands that actually terminate sessions.
See wire protocol and common fields. Source: gateway processor/constant.rs and processor/process.rs.