lib/logstorage: make a copy of s.partitions slice when performing queries over the selected partitions

s.partitions can be changed when new partition is registered or when old partition is dropped.
This could lead to data races and panics when s.partitions slice is accessed by concurrently executed queries.

The fix is to make a copy of the selected partitions under s.partitionsLock before performing the query.

docs/VictoriaLogs/CHANGELOG.md

@@ -15,6 +15,7 @@ according to [these docs](https://docs.victoriametrics.com/victorialogs/quicksta
 
 ## tip
 
+* BUGFIX: avoid possible panic when logs for a new day are ingested during execution of concurrent queries.
 * BUGFIX: avoid panic at `lib/logstorage.(*blockResultColumn).forEachDictValue()` when [stats with additional filters](https://docs.victoriametrics.com/victorialogs/logsql/#stats-with-additional-filters). The panic has been introduced in [v0.33.0](https://github.com/VictoriaMetrics/VictoriaMetrics/releases/tag/v0.33.0-victorialogs) in [this commit](https://github.com/VictoriaMetrics/VictoriaMetrics/commit/a350be48b68330ee1a487e1fb09b002d3be45163).
 
 

lib/logstorage/storage_search.go

@@ -685,6 +685,10 @@ func (s *Storage) search(workersCount int, so *genericSearchOptions, stopCh <-ch
 		return ptws[i].day > maxDay
 	})
 	ptws = ptws[:n]
+
+	// Copy the selected partitions, so they don't interfere with s.partitions.
+	ptws = append([]*partitionWrapper{}, ptws...)
+
 	for _, ptw := range ptws {
 		ptw.incRef()
 	}