How tags are stored and indexed in influxdb

Halo,

i have a question about how the tags are handled by influxdb, i will explain it better.

  • Are the tags stored in each shard? if yes there is a superstructure among shards that indexes the tags?
  • How are they stored? There is a structure like an inverted list, that points out for each combination tag+value, the records in which the tag is container?
  • How is build the indexing structure?

Thank you for the clarification.