[core] Fix race condition for earliest snapshot

paimon-core/src/main/java/org/apache/paimon/Changelog.java

@@ -28,6 +28,7 @@
 
 import javax.annotation.Nullable;
 
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.util.Map;
 
@@ -105,9 +106,19 @@ public static Changelog fromJson(String json) {
     }
 
     public static Changelog fromPath(FileIO fileIO, Path path) {
+        try {
+            return tryFromPath(fileIO, path);
+        } catch (FileNotFoundException e) {
+            throw new RuntimeException("Fails to read changelog from path " + path, e);
+        }
+    }
+
+    public static Changelog tryFromPath(FileIO fileIO, Path path) throws FileNotFoundException {
         try {
             String json = fileIO.readFileUtf8(path);
             return Changelog.fromJson(json);
+        } catch (FileNotFoundException e) {
+            throw e;
         } catch (IOException e) {
             throw new RuntimeException("Fails to read changelog from path " + path, e);
         }

paimon-core/src/main/java/org/apache/paimon/table/source/snapshot/IncrementalTimeStampStartingScanner.java

@@ -52,16 +52,8 @@ public Result scan(SnapshotReader reader) {
                 || endTimestamp < earliestSnapshot.timeMillis()) {
             return new NoSnapshot();
         }
-        // in org.apache.paimon.utils.SnapshotManager.earlierOrEqualTimeMills
-        // 1. if earliestSnapshotId or latestSnapshotId is null startingSnapshotId will be null
-        // 2. if earliestSnapShot.timeMillis() > startTimestamp startingSnapshotId will be
-        // earliestSnapShotId
-        // if  earliestSnapShot.timeMillis() > startTimestamp we should include the earliestSnapShot
-        // data
         Long startSnapshotId =
-                (startingSnapshotId == null || earliestSnapshot.timeMillis() > startTimestamp)
-                        ? earliestSnapshot.id() - 1
-                        : startingSnapshotId;
+                (startingSnapshotId == null) ? earliestSnapshot.id() - 1 : startingSnapshotId;
         Snapshot endSnapshot = snapshotManager.earlierOrEqualTimeMills(endTimestamp);
         Long endSnapshotId = (endSnapshot == null) ? latestSnapshot.id() : endSnapshot.id();
         IncrementalStartingScanner incrementalStartingScanner =

paimon-core/src/main/java/org/apache/paimon/table/source/snapshot/StaticFromTimestampStartingScanner.java

@@ -61,6 +61,16 @@ public SnapshotReader configure(SnapshotReader snapshotReader) {
 
     @Nullable
     public static Snapshot timeTravelToTimestamp(SnapshotManager snapshotManager, long timestamp) {
-        return snapshotManager.earlierOrEqualTimeMills(timestamp);
+        Snapshot snapshot = snapshotManager.earlierOrEqualTimeMills(timestamp);
+        if (snapshot == null) {
+            Long earliest = snapshotManager.earliestSnapshotId();
+            if (earliest != null) {
+                Snapshot earliestSnapShot = snapshotManager.snapshot(earliest);
+                if (earliestSnapShot.timeMillis() > timestamp) {
+                    snapshot = earliestSnapShot;
+                }
+            }
+        }
+        return snapshot;
     }
 }