Make sort_by_metric and sort_by_series independent controls instead of
the previous behavior where series sort was unconditionally appended
alongside the metric sort. This allows users to choose metric-only
sorting (enabling Druid TopN optimization) while optionally adding a
secondary series sort for tie-breaking.
Changes:
- buildQuery.ts: sort_by_metric and sort_by_series are now independent
- controlPanel.tsx: add sort_by_series checkbox (default: false)
- buildQuery.test.ts: cover all four sort combinations
- DB migration: set sort_by_series=true for existing word_cloud charts
to preserve backward compatibility
Fixes#39072
When sort_by_metric is true, buildQuery unconditionally appended a
secondary ORDER BY series ASC alongside the metric sort. On Druid, any
multi-column ORDER BY prevents the native TopN query optimization,
forcing a full GroupBy scan that can cause dramatic slowdowns and
timeouts on high-cardinality dimensions.
Make the series sort mutually exclusive with sort_by_metric, and add
test coverage for both sort behaviors.
Fixes#39072
