feat: TagValueIterator holds RLock for too long (#26369) (#26414)

devanbenz · web-flow · commit eb5acd88856b · 2025-05-13T14:34:07.000-05:00
diff --git a/tsdb/index/tsi1/log_file.go b/tsdb/index/tsi1/log_file.go
@@ -418,17 +418,19 @@ 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
`@@ -418,17 +418,19 @@ func (f *LogFile) TagValue(name, key, value []byte) TagValueElem {`
`418`	`418`	`// TagValueIterator returns a value iterator for a tag key.`
`419`	`419`	`func (f *LogFile) TagValueIterator(name, key []byte) TagValueIterator {`
`420`	`420`	`f.mu.RLock()`
`421`		`- defer f.mu.RUnlock()`
`422`	`421`
`423`	`422`	`mm, ok := f.mms[string(name)]`
`424`	`423`	`if !ok {`
	`424`	`+ f.mu.RUnlock()`
`425`	`425`	`return nil`
`426`	`426`	`}`
`427`	`427`
`428`	`428`	`tk, ok := mm.tagSet[string(key)]`
`429`	`429`	`if !ok {`
	`430`	`+ f.mu.RUnlock()`
`430`	`431`	`return nil`
`431`	`432`	`}`
	`433`	`+ f.mu.RUnlock()`
`432`	`434`	`return tk.TagValueIterator()`
`433`	`435`	`}`
`434`	`436`