badger: use a different transaction for each goroutine.

badger/query.go

@@ -35,19 +35,19 @@ func (b BadgerBackend) QueryEvents(ctx context.Context, filter nostr.Filter) (ch
 	}
 
 	go func() {
-		err := b.View(func(txn *badger.Txn) error {
+		defer close(ch)
+
+		// actually iterate
+		for _, q := range queries {
+			q := q
+			go b.View(func(txn *badger.Txn) error {
 				// iterate only through keys and in reverse order
 				opts := badger.IteratorOptions{
 					Reverse: true,
 				}
 
-			// actually iterate
-			iteratorClosers := make([]func(), len(queries))
-			for i, q := range queries {
-				go func(i int, q query) {
 				it := txn.NewIterator(opts)
-					iteratorClosers[i] = it.Close
-
+				defer it.Close()
 				defer close(q.results)
 
 				for it.Seek(q.startingPoint); it.ValidForPrefix(q.prefix); it.Next() {
@@ -72,11 +72,11 @@ func (b BadgerBackend) QueryEvents(ctx context.Context, filter nostr.Filter) (ch
 					item, err := txn.Get(idx)
 					if err != nil {
 						if err == badger.ErrDiscardedTxn {
-								return
+							return err
 						}
 						log.Printf("badger: failed to get %x based on prefix %x, index key %x from raw event store: %s\n",
 							idx, q.prefix, key, err)
-							return
+						return err
 					}
 					item.Value(func(val []byte) error {
 						evt := &nostr.Event{}
@@ -93,7 +93,9 @@ func (b BadgerBackend) QueryEvents(ctx context.Context, filter nostr.Filter) (ch
 						return nil
 					})
 				}
-				}(i, q)
+
+				return nil
+			})
 		}
 
 		// max number of events we'll return
@@ -114,17 +116,9 @@ func (b BadgerBackend) QueryEvents(ctx context.Context, filter nostr.Filter) (ch
 			}
 		}
 
-			// now it's a good time to schedule this
-			defer func() {
-				close(ch)
-				for _, itclose := range iteratorClosers {
-					itclose()
-				}
-			}()
-
 		// queue may be empty here if we have literally nothing
 		if len(emitQueue) == 0 {
-				return nil
+			return
 		}
 
 		heap.Init(&emitQueue)
@@ -155,12 +149,6 @@ func (b BadgerBackend) QueryEvents(ctx context.Context, filter nostr.Filter) (ch
 				}
 			}
 		}
-
-			return nil
-		})
-		if err != nil {
-			log.Printf("badger: query txn error: %s\n", err)
-		}
 	}()
 
 	return ch, nil