Pull request: 4850 stats: imp logging

Merge in DNS/adguard-home from 4850-imp-stats-logging to master

Updates AdguardTeam#4850.

Squashed commit of the following:

commit 3c1ee8d
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Aug 22 14:17:56 2022 +0300

    all: imp chlog

commit 0c7adc7
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Aug 22 14:12:01 2022 +0300

    stats: fix err check

commit d14a5ca
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Aug 22 14:09:15 2022 +0300

    stats: imp logging again

commit 34fc666
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Mon Aug 22 12:49:43 2022 +0300

    stats: imp code, logging

commit 09aa857
Merge: 09a732a eccfbf6
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Fri Aug 19 19:43:45 2022 +0300

    Merge branch 'master' into 4850-imp-stats-logging

commit 09a732a
Author: Eugene Burkov <E.Burkov@AdGuard.COM>
Date:   Fri Aug 19 19:38:51 2022 +0300

    stats: imp logging

CHANGELOG.md

@@ -28,7 +28,12 @@ and this project adheres to
   future release.
 - Go 1.18 support.  v0.109.0 will require at least Go 1.19 to build.
 
+### Fixed
+
+- Unnecessary logging of non-critical statistics errors ([#4850]).
+
 [#2993]: https://github.com/AdguardTeam/AdGuardHome/issues/2993
+[#4850]: https://github.com/AdguardTeam/AdGuardHome/issues/4850
 
 
 

internal/stats/stats.go

@@ -385,35 +385,39 @@ func (s *StatsCtx) flush() (cont bool, sleepFor time.Duration) {
 		return true, 0
 	}
 
+	isCommitable := true
 	tx, err := db.Begin(true)
 	if err != nil {
 		log.Error("stats: opening transaction: %s", err)
 
 		return true, 0
 	}
+	defer func() {
+		if err = finishTxn(tx, isCommitable); err != nil {
+			log.Error("stats: %s", err)
+		}
+	}()
 
 	s.curr = newUnit(id)
-	isCommitable := true
 
-	ferr := ptr.serialize().flushUnitToDB(tx, ptr.id)
-	if ferr != nil {
-		log.Error("stats: flushing unit: %s", ferr)
+	flushErr := ptr.serialize().flushUnitToDB(tx, ptr.id)
+	if flushErr != nil {
+		log.Error("stats: flushing unit: %s", flushErr)
 		isCommitable = false
 	}
 
-	derr := tx.DeleteBucket(idToUnitName(id - limit))
-	if derr != nil {
-		log.Error("stats: deleting unit: %s", derr)
-		if !errors.Is(derr, bbolt.ErrBucketNotFound) {
+	delErr := tx.DeleteBucket(idToUnitName(id - limit))
+	if delErr != nil {
+		// TODO(e.burkov):  Improve the algorithm of deleting the oldest bucket
+		// to avoid the error.
+		if errors.Is(delErr, bbolt.ErrBucketNotFound) {
+			log.Debug("stats: warning: deleting unit: %s", delErr)
+		} else {
 			isCommitable = false
+			log.Error("stats: deleting unit: %s", delErr)
 		}
 	}
 
-	err = finishTxn(tx, isCommitable)
-	if err != nil {
-		log.Error("stats: %s", err)
-	}
-
 	return true, 0
 }