[Hotfix] Fix incorrect Last Commit Time showing year 58000+ in partition view (#4083)

The last_updated_at column from Iceberg PARTITIONS metadata table stores
timestamps in microseconds, but it was passed directly to the frontend
which expects milliseconds. This caused the displayed year to be ~58000.

Convert microseconds to milliseconds by dividing by 1000, consistent
with how snapshot.timestampMillis() is used elsewhere.

Signed-off-by: Jiwon Park <[email protected]>

Author: j1wonpark

amoro-ams/src/main/java/org/apache/amoro/server/dashboard/MixedAndIcebergTableDescriptor.java

@@ -553,7 +553,9 @@ private List<PartitionBaseInfo> collectPartitionsFromTable(Table table) {
             // This will be updated once Iceberg supports reporting delete file sizes.
             // See: https://github.com/apache/iceberg/issues/14803
             partitionInfo.setFileSize(totalDataFileSize != null ? totalDataFileSize : 0L);
-            partitionInfo.setLastCommitTime(lastUpdatedAt != null ? lastUpdatedAt : 0L);
+            // last_updated_at from Iceberg PARTITIONS metadata table is in microseconds,
+            // convert to milliseconds for consistency with snapshot.timestampMillis()
+            partitionInfo.setLastCommitTime(lastUpdatedAt != null ? lastUpdatedAt / 1000 : 0L);
 
             partitions.add(partitionInfo);
           }

amoro-ams/src/test/java/org/apache/amoro/server/dashboard/TestIcebergServerTableDescriptor.java

@@ -107,15 +107,20 @@ public void testGetTablePartitions() {
     Assert.assertEquals("Should have 1 file total", 1, totalFiles);
 
     // Verify we used PARTITIONS metadata table which provides fileSize and lastCommitTime
+    // Year 2100 in milliseconds - any reasonable timestamp must be below this
+    long year2100InMillis = 4102444800000L;
     for (org.apache.amoro.table.descriptor.PartitionBaseInfo partition : partitions) {
       // File size should be available from PARTITIONS metadata table
       Assert.assertTrue(
           "FileSize should be available from PARTITIONS metadata table",
           partition.getFileSize() >= 0);
-      // Last commit time should be available from PARTITIONS metadata table
+      // Last commit time should be available and in milliseconds (not microseconds)
+      Assert.assertTrue("LastCommitTime should be positive", partition.getLastCommitTime() > 0);
       Assert.assertTrue(
-          "LastCommitTime should be available from PARTITIONS metadata table",
-          partition.getLastCommitTime() >= 0);
+          "LastCommitTime should be in milliseconds, not microseconds (got "
+              + partition.getLastCommitTime()
+              + ")",
+          partition.getLastCommitTime() < year2100InMillis);
     }
   }