box.space._schema

box.space._schema

_schema is a system space.

This space contains the following tuples:

• version tuple with version information for this Tarantool instance,
• cluster tuple with the instance’s replica set ID,
• max_id tuple with the maximal space ID,
• once... tuples that correspond to specific box.once() blocks from the instance’s initialization file. The first field in these tuples contains the key value from the corresponding box.once() block prefixed with ‘once’ (e.g. oncehello), so you can easily find a tuple that corresponds to a specific box.once() block.

Example:

Here is what _schema contains in a typical installation (notice the tuples for two box.once() blocks, 'oncebye' and 'oncehello'):

tarantool> box.space._schema:select{}
---
- - ['cluster', 'b4e15788-d962-4442-892e-d6c1dd5d13f2']
  - ['max_id', 512]
  - ['oncebye']
  - ['oncehello']
  - ['version', 1, 7, 2]