wip

Author: hmottestad

core/sail/nativerdf/src/main/java/org/eclipse/rdf4j/sail/nativerdf/TripleStore.java

@@ -80,6 +80,12 @@ class TripleStore implements Closeable {
 	 */
 	private static final String INDEXES_KEY = "triple-indexes";
 
+	/**
+	 * System property that enables the experimental {@link MemoryMappedTxnStatusFile} implementation instead of the
+	 * default {@link TxnStatusFile}.
+	 */
+	private static final String MEMORY_MAPPED_TXN_STATUS_FILE_ENABLED_PROP = "org.eclipse.rdf4j.sail.nativerdf.MemoryMappedTxnStatusFile.enabled";
+
 	/**
 	 * The version number for the current triple store.
 	 * <ul>
@@ -168,7 +174,7 @@ public TripleStore(File dir, String indexSpecStr) throws IOException, SailExcept
 	public TripleStore(File dir, String indexSpecStr, boolean forceSync) throws IOException, SailException {
 		this.dir = dir;
 		this.forceSync = forceSync;
-		this.txnStatusFile = new TxnStatusFile(dir);
+		this.txnStatusFile = createTxnStatusFile(dir);
 
 		File propFile = new File(dir, PROPERTIES_FILE);
 
@@ -223,6 +229,13 @@ public TripleStore(File dir, String indexSpecStr, boolean forceSync) throws IOEx
 		}
 	}
 
+	private static TxnStatusFile createTxnStatusFile(File dir) throws IOException {
+		if (Boolean.getBoolean(MEMORY_MAPPED_TXN_STATUS_FILE_ENABLED_PROP)) {
+			return new MemoryMappedTxnStatusFile(dir);
+		}
+		return new TxnStatusFile(dir);
+	}
+
 	/*---------*
 	 * Methods *
 	 *---------*/

core/sail/nativerdf/src/test/java/org/eclipse/rdf4j/sail/nativerdf/MemoryMappedTxnStatusFileConfigTest.java

@@ -0,0 +1,72 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Eclipse RDF4J contributors.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Distribution License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *******************************************************************************/
+package org.eclipse.rdf4j.sail.nativerdf;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.io.File;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+/**
+ * Verifies that the implementation used for the transaction status file can be controlled via a system property.
+ */
+public class MemoryMappedTxnStatusFileConfigTest {
+
+	private static final String MEMORY_MAPPED_ENABLED_PROP = "org.eclipse.rdf4j.sail.nativerdf.MemoryMappedTxnStatusFile.enabled";
+
+	@TempDir
+	File dataDir;
+
+	@AfterEach
+	public void clearProperty() {
+		System.clearProperty(MEMORY_MAPPED_ENABLED_PROP);
+	}
+
+	@Test
+	public void defaultUsesNioTxnStatusFile() throws Exception {
+		TripleStore tripleStore = new TripleStore(dataDir, "spoc");
+		try {
+			tripleStore.startTransaction();
+			tripleStore.storeTriple(1, 2, 3, 4);
+			tripleStore.commit();
+		} finally {
+			tripleStore.close();
+		}
+
+		File txnStatusFile = new File(dataDir, TxnStatusFile.FILE_NAME);
+		assertTrue(txnStatusFile.exists(), "Transaction status file should exist");
+		assertEquals(0L, txnStatusFile.length(),
+				"Default TxnStatusFile implementation truncates the file for NONE status");
+	}
+
+	@Test
+	public void memoryMappedEnabledUsesFixedSizeFile() throws Exception {
+		System.setProperty(MEMORY_MAPPED_ENABLED_PROP, "true");
+
+		TripleStore tripleStore = new TripleStore(dataDir, "spoc");
+		try {
+			tripleStore.startTransaction();
+			tripleStore.storeTriple(1, 2, 3, 4);
+			tripleStore.commit();
+		} finally {
+			tripleStore.close();
+		}
+
+		File txnStatusFile = new File(dataDir, TxnStatusFile.FILE_NAME);
+		assertTrue(txnStatusFile.exists(), "Transaction status file should exist");
+		assertEquals(1L, txnStatusFile.length(),
+				"Memory-mapped TxnStatusFile keeps a single status byte on disk for NONE status");
+	}
+}