feat: TagValueIterator holds RLock for too long (#26369) (#26372) (#26853)

devanbenz · web-flow · commit e51acc488259 · 2025-09-26T17:12:08.000-05:00
diff --git a/tsdb/index/tsi1/log_file.go b/tsdb/index/tsi1/log_file.go
@@ -421,17 +421,19 @@ func (f *LogFile) TagValue(name, key, value []byte) TagValueElem {
 // TagValueIterator returns a value iterator for a tag key.
 func (f *LogFile) TagValueIterator(name, key []byte) TagValueIterator {
 	f.mu.RLock()
-	defer f.mu.RUnlock()
 
 	mm, ok := f.mms[string(name)]
 	if !ok {
+		f.mu.RUnlock()
 		return nil
 	}
 
 	tk, ok := mm.tagSet[string(key)]
 	if !ok {
+		f.mu.RUnlock()
 		return nil
 	}
+	f.mu.RUnlock()
 	return tk.TagValueIterator()
 }
 

Original file line number	Diff line number	Diff line change
`@@ -421,17 +421,19 @@ func (f *LogFile) TagValue(name, key, value []byte) TagValueElem {`
`421`	`421`	`// TagValueIterator returns a value iterator for a tag key.`
`422`	`422`	`func (f *LogFile) TagValueIterator(name, key []byte) TagValueIterator {`
`423`	`423`	`f.mu.RLock()`
`424`		`- defer f.mu.RUnlock()`
`425`	`424`
`426`	`425`	`mm, ok := f.mms[string(name)]`
`427`	`426`	`if !ok {`
	`427`	`+ f.mu.RUnlock()`
`428`	`428`	`return nil`
`429`	`429`	`}`
`430`	`430`
`431`	`431`	`tk, ok := mm.tagSet[string(key)]`
`432`	`432`	`if !ok {`
	`433`	`+ f.mu.RUnlock()`
`433`	`434`	`return nil`
`434`	`435`	`}`
	`436`	`+ f.mu.RUnlock()`
`435`	`437`	`return tk.TagValueIterator()`
`436`	`438`	`}`
`437`	`439`