Meta queries (SHOW TAG VALUES, SHOW TAG KEYS, SHOW SERIES CARDINALITY, etc.) do not respect
the QueryTimeout config parameter. Meta queries should check the query context when possible
to allow cancellation and timeout. This will not be as frequent as regular queries, which
use iterators, because meta queries return data in batches.
Add a context.Context to
(*Store).MeasurementNames()
(*Store).MeasurementsCardinality()
(*Store).SeriesCardinality()
(*Store).TagValues()
(*Store).TagKeys()
(*Store).SeriesSketches()
(*Store).MeasurementsSketches()
which is tested for timeout or cancellation
to allow limitation of time spent in meta queries
https://github.com/influxdata/influxdb/issues/20736
This commit adds time support to SHOW TAG VALUES. Time can be used as
both a lower and upper boundary. However, there are some caveats.
For the `inmem` index, filtering by time will still return all results
because the index data is shared across shards.
For the `tsi1` index, filtering by time will only work down to the shard
lever. Specifically, when querying by time all shards within that time
range will be used to generate the results.
Sam Arnold
davidby-influx
Edd Robinson
Stuart Carnie
Joe LeGasse