apache · Jollyplum · Feb 13, 2026 · Mar 13, 2026 · Mar 23, 2026 · Mar 23, 2026
diff --git a/CHANGES.txt b/CHANGES.txt
@@ -1,5 +1,6 @@
 6.0-alpha1
  * Rework ZSTD dictionary compression logic to create a trainer per training (CASSANDRA-21209)
+ * Ensure schema created before 2.1 without tableId in folder name can be loaded in SnapshotLoader (CASSANDRA-21173)
  * Improve performance when calculating settled placements during range movements (CASSANDRA-21144)
  * Make shadow gossip round parameters configurable for testing (CASSANDRA-21149)
  * Avoid potential gossip thread deadlock during decommission (CASSANDRA-21143)
@@ -16,7 +17,7 @@
  * Allow overriding compaction strategy parameters during startup (CASSANDRA-21169)
  * Introduce created_at column to system_distributed.compression_dictionaries (CASSANDRA-21178)
  * Be able to detect and remove orphaned compression dictionaries (CASSANDRA-21157)
- * Fix BigTableVerifier to only read a data file during extended verification (CASSANDRA-21150) 
+ * Fix BigTableVerifier to only read a data file during extended verification (CASSANDRA-21150)
  * Reduce memory allocation during transformation of BatchStatement to Mutation (CASSANDRA-21141)
  * Direct I/O support for compaction reads (CASSANDRA-19987)
  * Support custom StartupCheck implementations via SPI (CASSANDRA-21093)

diff --git a/src/java/org/apache/cassandra/service/CassandraDaemon.java b/src/java/org/apache/cassandra/service/CassandraDaemon.java
@@ -272,14 +272,6 @@ protected void setup()
         Keyspace.setInitialized();
         CommitLog.instance.start();
 
-        SnapshotManager.instance.start(false);
-        SnapshotManager.instance.clearExpiredSnapshots();
-        SnapshotManager.instance.clearEphemeralSnapshots();
-        SnapshotManager.instance.resumeSnapshotCleanup();
-        SnapshotManager.instance.registerMBean();
-
-        // clearing of snapshots above here will in fact clear all ephemeral snapshots
-        // which were cleared as part of startup checks before CASSANDRA-18111
         runStartupChecks();
 
         try
@@ -306,6 +298,17 @@ protected void setup()
             exitOrFail(e.returnCode, e.getMessage(), e.getCause());
         }
 
+        // SnapshotManager is started after Startup.initialize so that ClusterMetadata is available,
+        // allowing SnapshotLoader to resolve tableId for pre-2.1 tables via ColumnFamilyStore.
+        // This means ephemeral/expired snapshot cleanup now runs later in startup than before
+        // CASSANDRA-21173. No default StartupChecks depend on snapshot state, but custom
+        // StartupCheck implementations that check disk space may observe stale snapshots.
+        SnapshotManager.instance.start(false);
+        SnapshotManager.instance.clearExpiredSnapshots();
+        SnapshotManager.instance.clearEphemeralSnapshots();
+        SnapshotManager.instance.resumeSnapshotCleanup();
+        SnapshotManager.instance.registerMBean();
+
         QueryProcessor.registerStatementInvalidatingListener();
 
         try

diff --git a/src/java/org/apache/cassandra/service/snapshot/SnapshotLoader.java b/src/java/org/apache/cassandra/service/snapshot/SnapshotLoader.java
@@ -37,14 +37,19 @@
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
+import javax.annotation.Nullable;
+
 import com.google.common.annotations.VisibleForTesting;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import org.apache.cassandra.config.DatabaseDescriptor;
+import org.apache.cassandra.db.ColumnFamilyStore;
 import org.apache.cassandra.db.Directories;
+import org.apache.cassandra.db.Keyspace;
 import org.apache.cassandra.io.util.File;
+import org.apache.cassandra.tcm.ClusterMetadata;
 
 import static org.apache.cassandra.db.Directories.SNAPSHOT_SUBDIR;
 import static org.apache.cassandra.service.snapshot.TableSnapshot.buildSnapshotId;
@@ -56,7 +61,9 @@ public class SnapshotLoader
 {
     private static final Logger logger = LoggerFactory.getLogger(SnapshotLoader.class);
 
-    static final Pattern SNAPSHOT_DIR_PATTERN = Pattern.compile("(?<keyspace>\\w+)/(?<tableName>\\w+)-(?<tableId>[0-9a-f]{32})/snapshots/(?<tag>.+)$");
+    static final Pattern SNAPSHOT_DIR_PATTERN = Pattern.compile("(?<keyspace>\\w+)/(?<tableName>\\w+)" +
+                                                                "(-(?<tableId>[0-9a-f]{32}))?" +
+                                                                "/snapshots/(?<tag>.+)$");
 
     private final Collection<Path> dataDirectories;
 
@@ -151,12 +158,47 @@ private void loadSnapshotFromDir(Matcher snapshotDirMatcher, Path snapshotDir)
         {
             String keyspaceName = snapshotDirMatcher.group("keyspace");
             String tableName = snapshotDirMatcher.group("tableName");
-            UUID tableId = parseUUID(snapshotDirMatcher.group("tableId"));
+            final UUID tableId = maybeDetermineTableId(snapshotDirMatcher, snapshotDir, keyspaceName, tableName);
             String tag = snapshotDirMatcher.group("tag");
             String snapshotId = buildSnapshotId(keyspaceName, tableName, tableId, tag);
             TableSnapshot.Builder builder = snapshots.computeIfAbsent(snapshotId, k -> new TableSnapshot.Builder(keyspaceName, tableName, tableId, tag));
             builder.addSnapshotDir(new File(snapshotDir).toAbsolute());
         }
+
+        private @Nullable UUID maybeDetermineTableId(Matcher snapshotDirMatcher, Path snapshotDir, String keyspaceName, String tableName)
+        {
+            final UUID tableId;
+            if (snapshotDirMatcher.group("tableId") == null)
+            {
+                logger.debug("Snapshot directory without tableId found (pre-2.1 format): {}", snapshotDir);
+                // If we don't have a tableId in folder name (e.g pre 2.1 created table)
+                // Then attempt to get tableId from CFS on startup
+                // falling back to null is fine as it still yields a unique result in buildSnapshotId for pre-2.1 table
+                if (Keyspace.isInitialized() && ClusterMetadata.currentNullable() != null)
+                {
+                    ColumnFamilyStore cfs = ColumnFamilyStore.getIfExists(keyspaceName, tableName);
+                    tableId = cfs != null && cfs.metadata != null && cfs.metadata.id != null
+                              ? cfs.metadata.id.asUUID()
+                              : null;
+                    if (tableId == null)
+                    {
+                        logger.warn("Snapshot directory without tableId found (pre-2.1 format), " +
+                                    "unable to resolve table id from column family, defaulting to null, snapshot dir: {}", snapshotDir);
+                    }
+                }
+                else
+                {
+                    logger.warn("Snapshot directory without tableId found (pre-2.1 format), " +
+                                "TCM or keyspace is not initialized or there is a schema missing, defaulting to null, snapshot dir: {}", snapshotDir);
+                    tableId = null;
+                }
+            }
+            else
+            {
+                tableId = parseUUID(snapshotDirMatcher.group("tableId"));
+            }
+            return tableId;
+        }
     }
 
     public Set<TableSnapshot> loadSnapshots(String keyspace)

diff --git a/src/java/org/apache/cassandra/service/snapshot/TableSnapshot.java b/src/java/org/apache/cassandra/service/snapshot/TableSnapshot.java
@@ -35,6 +35,8 @@
 import java.util.UUID;
 import java.util.stream.Stream;
 
+import javax.annotation.Nullable;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -68,6 +70,9 @@ public class TableSnapshot
     private final String keyspaceName;
     private final String tableName;
     private final String keyspaceTable;
+    // tableId may be null under some rare circumstance namely pre-2.1 table
+    // whose snapshot is loaded upon startup rather than created while the jvm is running
+    @Nullable
     private final UUID tableId;
     private final String tag;
     private final boolean ephemeral;
@@ -121,6 +126,7 @@ public void complete()
      * Unique identifier of a snapshot. Used
      * only to deduplicate snapshots internally,
      * not exposed externally.
+     * table_id may be empty for tables created prior to 2.1
      * <p>
      * Format: "$ks:$table_name:$table_id:$tag"
      */
@@ -650,9 +656,9 @@ private void writeManifest(SnapshotManifest snapshotManifest, File manifestFile)
         }
     }
 
-    protected static String buildSnapshotId(String keyspaceName, String tableName, UUID tableId, String tag)
+    protected static String buildSnapshotId(String keyspaceName, String tableName, @Nullable UUID tableId, String tag)
     {
-        return String.format("%s:%s:%s:%s", keyspaceName, tableName, tableId, tag);
+        return String.format("%s:%s:%s:%s", keyspaceName, tableName, tableId == null ? "" : tableId, tag);
     }
 
     public static Set<Descriptor> getSnapshotDescriptors(String keyspace, String table, String tag)

diff --git a/test/unit/org/apache/cassandra/service/snapshot/SnapshotLoaderTest.java b/test/unit/org/apache/cassandra/service/snapshot/SnapshotLoaderTest.java
@@ -38,6 +38,7 @@
 import org.apache.cassandra.config.DatabaseDescriptor;
 import org.apache.cassandra.config.DurationSpec;
 import org.apache.cassandra.db.Directories;
+import org.apache.cassandra.db.Keyspace;
 import org.apache.cassandra.io.util.File;
 import org.apache.cassandra.utils.Clock;
 
@@ -75,6 +76,7 @@ public class SnapshotLoaderTest
     public static void setup()
     {
         DatabaseDescriptor.daemonInitialization();
+        Keyspace.setInitialized();
     }
 
     @Test
@@ -86,6 +88,9 @@ public void testMatcher()
         String TABLE_SNAPSHOT = "/Users/pmottagomes/.ccm/test/node1/data0/ks/my_table-1a025b40c58f11eca526336fc2c671ab/snapshots/test";
         assertThat(SNAPSHOT_DIR_PATTERN.matcher(TABLE_SNAPSHOT).find()).isTrue();
 
+        String TABLE_SNAPSHOT_PRE_21 = "/Users/pmottagomes/.ccm/test/node1/data0/ks/my_table/snapshots/test";
+        assertThat(SNAPSHOT_DIR_PATTERN.matcher(TABLE_SNAPSHOT_PRE_21).find()).isTrue();
+
         String DROPPED_SNAPSHOT = "/Users/pmottagomes/.ccm/test/node1/data0/ks/my_table-e5c58330c58d11eca526336fc2c671ab/snapshots/dropped-1650997415751-my_table";
         assertThat(SNAPSHOT_DIR_PATTERN.matcher(DROPPED_SNAPSHOT).find()).isTrue();
     }
@@ -124,24 +129,20 @@ public void testSnapshotsWithoutManifests() throws IOException
         for (String dataDir : DATA_DIRS)
         {
             firstSnapshotDirs.add(createDir(baseDir, dataDir, KEYSPACE_1, tableDirName(TABLE1_NAME, TABLE1_ID), Directories.SNAPSHOT_SUBDIR, TAG1));
-            secondSnapshotDirs.add(createDir(baseDir, dataDir, KEYSPACE_1, tableDirName(TABLE2_NAME, TABLE2_ID), Directories.SNAPSHOT_SUBDIR, TAG2));
+            secondSnapshotDirs.add(createDir(baseDir, dataDir, KEYSPACE_1, TABLE2_NAME, Directories.SNAPSHOT_SUBDIR, TAG2));
             thirdSnapshotDirs.add(createDir(baseDir, dataDir, KEYSPACE_2, tableDirName(TABLE3_NAME, TABLE3_ID), Directories.SNAPSHOT_SUBDIR, TAG3));
         }
 
         Instant createdAt = Instant.ofEpochMilli(Clock.Global.currentTimeMillis());
 
-        createManifests(firstSnapshotDirs, createdAt);
-        createManifests(secondSnapshotDirs, createdAt);
-        createManifests(thirdSnapshotDirs, createdAt);
-
         // Verify all 3 snapshots are found correctly from data directories
         SnapshotLoader loader = new SnapshotLoader(Arrays.asList(Paths.get(baseDir.toString(), DATA_DIR_1),
                                                                  Paths.get(baseDir.toString(), DATA_DIR_2),
                                                                  Paths.get(baseDir.toString(), DATA_DIR_3)));
         Set<TableSnapshot> snapshots = loader.loadSnapshots();
         assertThat(snapshots).hasSize(3);
         assertThat(snapshots).contains(new TableSnapshot(KEYSPACE_1, TABLE1_NAME, TABLE1_ID, TAG1, createdAt, null, firstSnapshotDirs, false));
-        assertThat(snapshots).contains(new TableSnapshot(KEYSPACE_1, TABLE2_NAME, TABLE2_ID, TAG2, createdAt, null, secondSnapshotDirs, false));
+        assertThat(snapshots).contains(new TableSnapshot(KEYSPACE_1, TABLE2_NAME, null, TAG2, createdAt, null, secondSnapshotDirs, false));
         assertThat(snapshots).contains(new TableSnapshot(KEYSPACE_2, TABLE3_NAME, TABLE3_ID, TAG3, createdAt, null, thirdSnapshotDirs, false));
 
         // Verify snapshot loading for a specific keyspace
@@ -152,7 +153,7 @@ public void testSnapshotsWithoutManifests() throws IOException
         snapshots = loader.loadSnapshots(KEYSPACE_1);
         assertThat(snapshots).hasSize(2);
         assertThat(snapshots).contains(new TableSnapshot(KEYSPACE_1, TABLE1_NAME, TABLE1_ID, TAG1, createdAt, null, firstSnapshotDirs, false));
-        assertThat(snapshots).contains(new TableSnapshot(KEYSPACE_1, TABLE2_NAME, TABLE2_ID,  TAG2, createdAt, null, secondSnapshotDirs, false));
+        assertThat(snapshots).contains(new TableSnapshot(KEYSPACE_1, TABLE2_NAME, null,  TAG2, createdAt, null, secondSnapshotDirs, false));
 
         loader = new SnapshotLoader(Arrays.asList(Paths.get(baseDir.toString(), DATA_DIR_1),
                                                   Paths.get(baseDir.toString(), DATA_DIR_2),
@@ -227,7 +228,8 @@ public void testSnapshotsWithManifests() throws IOException
         for (String dataDir : DATA_DIRS)
         {
             tag1Files.add(createDir(baseDir, dataDir, KEYSPACE_1, tableDirName(TABLE1_NAME, TABLE1_ID), Directories.SNAPSHOT_SUBDIR, TAG1));
-            tag2Files.add(createDir(baseDir, dataDir, KEYSPACE_1, tableDirName(TABLE2_NAME, TABLE2_ID), Directories.SNAPSHOT_SUBDIR, TAG2));
+            // One table is an old pre 2.1 table folder structure
+            tag2Files.add(createDir(baseDir, dataDir, KEYSPACE_1, TABLE2_NAME, Directories.SNAPSHOT_SUBDIR, TAG2));
             tag3Files.add(createDir(baseDir, dataDir, KEYSPACE_2, tableDirName(TABLE3_NAME, TABLE3_ID), Directories.SNAPSHOT_SUBDIR, TAG3));
         }
 
@@ -254,7 +256,7 @@ public void testSnapshotsWithManifests() throws IOException
         Set<TableSnapshot> snapshots = loader.loadSnapshots();
         assertThat(snapshots).hasSize(3);
         assertThat(snapshots).contains(new TableSnapshot(KEYSPACE_1, TABLE1_NAME, TABLE1_ID, TAG1, tag1Ts, null, tag1Files, false));
-        assertThat(snapshots).contains(new TableSnapshot(KEYSPACE_1, TABLE2_NAME, TABLE2_ID,  TAG2, tag2Ts, tag2Ts.plusSeconds(tag2Ttl.toSeconds()), tag2Files, false));
+        assertThat(snapshots).contains(new TableSnapshot(KEYSPACE_1, TABLE2_NAME, null,  TAG2, tag2Ts, tag2Ts.plusSeconds(tag2Ttl.toSeconds()), tag2Files, false));
         assertThat(snapshots).contains(new TableSnapshot(KEYSPACE_2, TABLE3_NAME, TABLE3_ID,  TAG3, tag3Ts, null, tag3Files, false));
 
         // Verify snapshot loading for a specific keyspace
@@ -265,7 +267,7 @@ public void testSnapshotsWithManifests() throws IOException
         snapshots = loader.loadSnapshots(KEYSPACE_1);
         assertThat(snapshots).hasSize(2);
         assertThat(snapshots).contains(new TableSnapshot(KEYSPACE_1, TABLE1_NAME, TABLE1_ID, TAG1, tag1Ts, null, tag1Files, false));
-        assertThat(snapshots).contains(new TableSnapshot(KEYSPACE_1, TABLE2_NAME, TABLE2_ID,  TAG2, tag2Ts, tag2Ts.plusSeconds(tag2Ttl.toSeconds()), tag2Files, false));
+        assertThat(snapshots).contains(new TableSnapshot(KEYSPACE_1, TABLE2_NAME, null,  TAG2, tag2Ts, tag2Ts.plusSeconds(tag2Ttl.toSeconds()), tag2Files, false));
 
         loader = new SnapshotLoader(Arrays.asList(Paths.get(baseDir.toString(), DATA_DIR_1),
                                                   Paths.get(baseDir.toString(), DATA_DIR_2),