Merge pull request #649 from molecula/fix-rbf-rollback

Fix RBF checkpoint high water mark

rbf/db.go

@@ -187,6 +187,7 @@ func (db *DB) checkpoint() error {
 	// Loop over each transaction
 	walID++
 	pageMap := immutable.NewMap(&uint32Hasher{})
+	var maxCheckpointedWALID int64
 	for {
 		// Determine last page of transaction.
 		metaWALID, metaFlags, err := db.findNextWALMetaPage(walID)
@@ -240,20 +241,27 @@ func (db *DB) checkpoint() error {
 			if err := db.writePage(pgno, page); err != nil {
 				return err
 			}
+
+			// Track highest WALID that has been checkpointed back to disk.
+			if IsMetaPage(page) {
+				maxCheckpointedWALID = walID
+			}
 		}
 	}
 
 	// Remove WAL segments that have been checkpointed.
-	for len(db.segments) > 1 {
-		segment := db.segments[0]
-		if minActiveWALID != 0 && segment.MaxWALID() >= minActiveWALID {
-			break
-		}
+	if maxCheckpointedWALID != 0 {
+		for len(db.segments) > 1 {
+			segment := db.segments[0]
+			if segment.MaxWALID() >= maxCheckpointedWALID {
+				break
+			}
 
-		if err := segment.Close(); err != nil {
-			return err
+			if err := segment.Close(); err != nil {
+				return err
+			}
+			db.segments, db.segments[0] = db.segments[1:], nil
 		}
-		db.segments, db.segments[0] = db.segments[1:], nil
 	}
 
 	db.pageMap = pageMap
@@ -590,8 +598,10 @@ func (db *DB) removeTx(tx *Tx) error {
 
 	// Write pages from WAL to DB.
 	// TODO(bbj): Move this to an async goroutine.
-	if err := db.checkpoint(); err != nil {
-		return err
+	if tx.writable {
+		if err := db.checkpoint(); err != nil {
+			return err
+		}
 	}
 
 	delete(tx.db.txs, tx)

rbf/tx.go

@@ -106,18 +106,8 @@ func (tx *Tx) Rollback() {
 		}
 	}
 
-	// turn on these error checks! we see
-	// panic: cannot find segment containing WAL page: 1
-	// when running go test -v
-	// TestCursor_FirstNext_Quick/6
-	//
-	//panicOn(tx.db.checkpoint())
-	//panicOn(tx.db.removeTx(tx))
-
-	_ = tx.db.checkpoint()
-
 	// Disconnect transaction from DB.
-	_ = tx.db.removeTx(tx)
+	panicOn(tx.db.removeTx(tx))
 }
 
 // Root returns the root page number for a bitmap. Returns 0 if the bitmap does not exist.