fixes after review

Author: hmottestad

core/sail/lmdb/src/main/java/org/eclipse/rdf4j/sail/lmdb/TxnManager.java

@@ -45,6 +45,9 @@ class TxnManager {
 	private static final long READERS_FULL_WAIT_MILLIS = 10L;
 
 	private final Mode mode;
+	/**
+	 * Live transactions keyed by reference. The value controls whether {@link #reset()} should renew the transaction.
+	 */
 	private final IdentityHashMap<Txn, Boolean> active = new IdentityHashMap<>();
 	private final long[] pool;
 	private final StampedLongAdderLockManager lockManager = new StampedLongAdderLockManager();
@@ -228,7 +231,7 @@ void deactivate() throws IOException {
 	}
 
 	void reset() throws IOException {
-		for (Txn txn : activeTransactions()) {
+		for (Txn txn : resettableActiveTransactions()) {
 			txn.reset();
 		}
 	}
@@ -239,12 +242,21 @@ private List<Txn> activeTransactions() {
 		}
 	}
 
+	private List<Txn> resettableActiveTransactions() {
+		synchronized (active) {
+			List<Txn> transactions = new ArrayList<>();
+			active.forEach((txn, resetOnWrite) -> {
+				if (Boolean.TRUE.equals(resetOnWrite)) {
+					transactions.add(txn);
+				}
+			});
+			return transactions;
+		}
+	}
+
 	private void updateActiveState(Txn txn, boolean isActive) {
 		synchronized (active) {
-			if (active.containsKey(txn)) {
-				active.put(txn, isActive);
-			}
-			if (!isActive) {
+			if (active.containsKey(txn) && !isActive) {
 				active.notifyAll();
 			}
 		}

core/sail/lmdb/src/test/java/org/eclipse/rdf4j/sail/lmdb/TxnManagerTest.java

@@ -96,6 +96,36 @@ public void resetDoesNotAbortTrackedInactiveTxn(@TempDir Path dataDir) throws Ex
 		}
 	}
 
+	@Test
+	public void resetSkipsUntrackedReadTxn(@TempDir Path dataDir) throws Exception {
+		long env = openEnv(dataDir, 2);
+		TxnManager.Txn trackedTxn = null;
+		TxnManager.Txn untrackedTxn = null;
+
+		try {
+			TxnManager txnManager = new TxnManager(env, TxnManager.Mode.RESET);
+			trackedTxn = txnManager.createReadTxn();
+			untrackedTxn = txnManager.createReadTxnUntracked();
+			long trackedVersion = trackedTxn.version();
+			long version = untrackedTxn.version();
+
+			txnManager.reset();
+
+			assertEquals(trackedVersion + 1, trackedTxn.version(),
+					"Reset must still renew regular tracked transactions");
+			assertEquals(version, untrackedTxn.version(),
+					"Reset must not renew untracked transactions owned by long-running refresh readers");
+		} finally {
+			if (trackedTxn != null) {
+				trackedTxn.close();
+			}
+			if (untrackedTxn != null) {
+				untrackedTxn.close();
+			}
+			mdb_env_close(env);
+		}
+	}
+
 	private static long openEnv(Path dataDir, int maxReaders) throws IOException {
 		try (MemoryStack stack = stackPush()) {
 			PointerBuffer pp = stack.mallocPointer(1);