This improves performance for analytical queries, which do not need column headers metadata.
For example, the following query doesn't need column headers metadata, since _stream and min(_time)
are stored in block header, which is read separately from colum headers metadata:
_time:1w | stats by (_stream) min(_time) min_time
This commit significantly improves the performance for this query.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/7070
Substitute global streamTagsCache with per-blockSearch cache for ((stream.id) -> (_stream value)) entries.
This improves scalability of obtaining _stream values on a machine with many CPU cores, since every CPU
has its own blockSearch instance.
This also should reduce memory usage when querying logs over big number of streams, since per-blockSearch
cache of ((stream.id) -> (_stream value)) entries is limited in size, and its lifetime is bounded by a single query.
