Core: Commit empty operations from SetSnapshotOperation (apache#5536)

Change-Id: I9b481ca173a12457cb6773ade0c8a1ebd0b40cbc
deniskuzZ · Aug 15, 2022 · c550e79 · c550e79
1 parent ce5128f
commit c550e79
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Showing 2 changed files with 15 additions and 6 deletions.
diff --git a/core/src/main/java/org/apache/iceberg/SetSnapshotOperation.java b/core/src/main/java/org/apache/iceberg/SetSnapshotOperation.java
@@ -123,12 +123,10 @@ public void commit() {
                       .setBranchSnapshot(snapshot.snapshotId(), SnapshotRef.MAIN_BRANCH)
                       .build();
 
-              if (updated.changes().isEmpty()) {
-                // do not commit if the metadata has not changed. for example, this may happen when
-                // setting the current
-                // snapshot to an ID that is already current. note that this check uses identity.
-                return;
-              }
+              // Do commit this operation even if the metadata has not changed, as we need to
+              // advance the hasLastOpCommited for the transaction's commit to work properly.
+              // (Without any other operations in the transaction, the commitTransaction() call
+              // will be a no-op anyway)
 
               // if the table UUID is missing, add it here. the UUID will be re-created each time
               // this operation retries

diff --git a/core/src/test/java/org/apache/iceberg/TestSnapshotManager.java b/core/src/test/java/org/apache/iceberg/TestSnapshotManager.java
@@ -621,4 +621,15 @@ public void testCreateReferencesAndCherrypick() {
     Assert.assertEquals(SnapshotRef.branchBuilder(1).build(), actualBranch);
     Assert.assertEquals(SnapshotRef.tagBuilder(1).build(), actualTag);
   }
+
+  @Test
+  public void testAttemptToRollbackToCurrentSnapshot() {
+    table.newAppend().appendFile(FILE_A).commit();
+
+    long currentSnapshotTimestampPlus100 = table.currentSnapshot().timestampMillis() + 100;
+    table.manageSnapshots().rollbackToTime(currentSnapshotTimestampPlus100).commit();
+
+    long currentSnapshotId = table.currentSnapshot().snapshotId();
+    table.manageSnapshots().rollbackTo(currentSnapshotId).commit();
+  }
 }