Submodule box.info | Tarantool

Submodule box.info

The box.info submodule provides access to information about server instance variables.

  • cluster.uuid is the UUID of the replica set. Every instance in a replica set will have the same cluster.uuid value. This value is also stored in box.space._schema system space.
  • gc() returns the state of the Tarantool garbage collector including the checkpoints and their consumers (users); see details here.
  • id corresponds to replication[n].id (see here).
  • lsn corresponds to replication[n].lsn (see here).
  • listen returns a real address to which an instance was bound (see here).
  • memory() returns the statistics about memory (see here).
  • pid is the process ID. This value is also shown by tarantool module and by the Linux command ps -A.
  • ro is true if the instance is in read-only mode (same as read_only in box.cfg{}), or if status is ‘orphan’.
  • ro_reason is nil if the instance is in writable mode. When the field is not nil, it contains the reason why the instance is read-only. Possible error reasons: election, synchro, config, and orphan (see box.info.ro_reason for details).
  • signature is the sum of all lsn values from each vector clock (vclock) for all instances in the replica set.
  • sql().cache.size is the number of bytes in the SQL prepared statement cache.
  • sql().cache.stmt_count is the number of statements in the SQL prepared statement cache.
  • status is the current state of the instance. It can be:
    • running – the instance is loaded,
    • loading – the instance is either recovering xlogs/snapshots or bootstrapping,
    • orphan – the instance has not (yet) succeeded in joining the required number of masters (see orphan status),
    • hot_standby – the instance is standing by another instance.
  • uptime is the number of seconds since the instance started. This value can also be retrieved with tarantool.uptime().
  • uuid corresponds to replication[n].uuid (see here).
  • vclock is a table with the vclock values of all instances in a replica set which have made data changes.
  • version is the Tarantool version. This value is also shown by tarantool -V.
  • vinyl() returns runtime statistics for the vinyl storage engine. This function is deprecated, use box.stat.vinyl() instead.
  • election shows the current state of a replica set node regarding leader election (see here).

Below is a list of all box.info functions and members.

Name Use
box.info() Return all keys and values provided in the submodule
box.info.gc() Return info about garbage collector
box.info.memory() Return info about memory usage
box.info.replication_anon() List all the anonymous replicas following the instance
box.info.replication Return statistics for all instances in the replica set
box.info.listen Return a real address to which an instance was bound
box.info.election Show the current state of a replica set node in regards to leader election
box.info.synchro Show the current state of synchronous replication
box.info.ro_reason Show the current mode of an instance (writable or read-only)
box.info.schema_version Show the database schema version
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