Avoid redundant decoding when sendind coordinate to change tracker or coverage index.

Don't try to store in coverage index if the key already exists.
Handle more potential database errors.

cmd/mtredisalize/changetracker.go

@@ -27,13 +27,7 @@ func NewChangeTracker() *ChangeTracker {
 	return &ChangeTracker{changes: make(map[quantizedXZ]bool)}
 }
 
-func (ct *ChangeTracker) BlockChanged(key []byte) {
+func (ct *ChangeTracker) BlockChanged(coord common.Coord) {
-	var err error
-	var coord common.Coord
-	if coord, err = common.DecodeStringBytesToCoord(key); err != nil {
-		log.Printf("decoding key failed: %s\n", err)
-		return
-	}
 	ct.mutex.Lock()
 	ct.changes[quantizedXZ{
 		X: coord.X / quantizationFactor,

cmd/mtredisalize/leveldb.go

@@ -189,17 +189,22 @@ func (ldbs *LevelDBSession) Store(hash, key, value []byte) (exists bool, err err
 		err = db.Put(wo, key, value)
 		wo.Close()
 	})
-	// This technically too early because this done in transactions
+	if err != nil {
+		return
+	}
+	// This technically too early because this is done in a transactions
 	// which are commited (and possible fail) later.
-	if ldbs.backend.coverage != nil {
+	if ldbs.backend.changeTracker != nil || ldbs.backend.coverage != nil {
 		c, err := common.DecodeStringBytesToCoord(origKey)
 		if err != nil {
-			return false, err
+			return exists, err
+		}
+		if ldbs.backend.coverage != nil && !exists {
+			ldbs.backend.coverage.Insert(c)
+		}
+		if ldbs.backend.changeTracker != nil {
+			ldbs.backend.changeTracker.BlockChanged(c)
 		}
-		ldbs.backend.coverage.Insert(c)
-	}
-	if ldbs.backend.changeTracker != nil {
-		ldbs.backend.changeTracker.BlockChanged(origKey)
 	}
 	return
 }

cmd/mtredisalize/sqlite.go

@@ -239,15 +239,21 @@ func (ss *SqliteSession) Store(hash, key, value []byte) (exists bool, err error)
 		insertStmt := ss.txStmt(ss.backend.insertStmt)
 		_, err = insertStmt.Exec(pos, value)
 	}
-	// This technically too early because this done in transactions
+	if err != nil {
+		return
+	}
+	// This technically too early because this is done in a transactions
 	// which are commited (and possible fail) later.
-	if ss.backend.coverage != nil {
+	if ss.backend.changeTracker != nil || ss.backend.coverage != nil {
-		ss.backend.coverage.Insert(common.PlainToCoord(pos))
+		c := common.PlainToCoord(pos)
+		if ss.backend.coverage != nil && !exists {
+			ss.backend.coverage.Insert(c)
+		}
+		if ss.backend.changeTracker != nil {
+			ss.backend.changeTracker.BlockChanged(c)
+		}
 	}
 
-	if ss.backend.changeTracker != nil {
-		ss.backend.changeTracker.BlockChanged(key)
-	}
 	return
 }