From 645272177d9d7c01a895da969a34a993f52772ec Mon Sep 17 00:00:00 2001
From: zhangdong <zhangdong@selectdb.com>
Date: Wed, 13 Nov 2024 17:05:24 +0800
Subject: [PATCH] [core] Partitions system table support time travel (#4511)

---
 .../paimon/table/system/PartitionsTable.java  |  2 +-
 .../table/system/PartitionsTableTest.java     | 24 ++++++++++++++++---
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/paimon-core/src/main/java/org/apache/paimon/table/system/PartitionsTable.java b/paimon-core/src/main/java/org/apache/paimon/table/system/PartitionsTable.java
index 76c0768eeeac..4aaeee425479 100644
--- a/paimon-core/src/main/java/org/apache/paimon/table/system/PartitionsTable.java
+++ b/paimon-core/src/main/java/org/apache/paimon/table/system/PartitionsTable.java
@@ -176,7 +176,7 @@ public RecordReader<InternalRow> createReader(Split split) throws IOException {
                 throw new IllegalArgumentException("Unsupported split: " + split.getClass());
             }
 
-            List<PartitionEntry> partitions = fileStoreTable.newSnapshotReader().partitionEntries();
+            List<PartitionEntry> partitions = fileStoreTable.newScan().listPartitionEntries();
 
             RowDataToObjectArrayConverter converter =
                     new RowDataToObjectArrayConverter(
diff --git a/paimon-core/src/test/java/org/apache/paimon/table/system/PartitionsTableTest.java b/paimon-core/src/test/java/org/apache/paimon/table/system/PartitionsTableTest.java
index a17dc75466a6..8d12dc707bf5 100644
--- a/paimon-core/src/test/java/org/apache/paimon/table/system/PartitionsTableTest.java
+++ b/paimon-core/src/test/java/org/apache/paimon/table/system/PartitionsTableTest.java
@@ -40,6 +40,7 @@
 import org.junit.jupiter.api.Test;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -76,7 +77,7 @@ public void before() throws Exception {
         partitionsTable = (PartitionsTable) catalog.getTable(filesTableId);
 
         // snapshot 1: append
-        write(table, GenericRow.of(1, 1, 1), GenericRow.of(1, 2, 5));
+        write(table, GenericRow.of(1, 1, 1), GenericRow.of(1, 3, 5));
 
         write(table, GenericRow.of(1, 1, 3), GenericRow.of(1, 2, 4));
     }
@@ -85,19 +86,36 @@ public void before() throws Exception {
     public void testPartitionRecordCount() throws Exception {
         List<InternalRow> expectedRow = new ArrayList<>();
         expectedRow.add(GenericRow.of(BinaryString.fromString("[1]"), 2L));
-        expectedRow.add(GenericRow.of(BinaryString.fromString("[2]"), 2L));
+        expectedRow.add(GenericRow.of(BinaryString.fromString("[2]"), 1L));
+        expectedRow.add(GenericRow.of(BinaryString.fromString("[3]"), 1L));
 
         // Only read partition and record count, record size may not stable.
         List<InternalRow> result = read(partitionsTable, new int[][] {{0}, {1}});
         assertThat(result).containsExactlyInAnyOrderElementsOf(expectedRow);
     }
 
+    @Test
+    public void testPartitionTimeTravel() throws Exception {
+        List<InternalRow> expectedRow = new ArrayList<>();
+        expectedRow.add(GenericRow.of(BinaryString.fromString("[1]"), 1L));
+        expectedRow.add(GenericRow.of(BinaryString.fromString("[3]"), 1L));
+
+        // Only read partition and record count, record size may not stable.
+        List<InternalRow> result =
+                read(
+                        partitionsTable.copy(
+                                Collections.singletonMap(CoreOptions.SCAN_VERSION.key(), "1")),
+                        new int[][] {{0}, {1}});
+        assertThat(result).containsExactlyInAnyOrderElementsOf(expectedRow);
+    }
+
     @Test
     public void testPartitionValue() throws Exception {
         write(table, GenericRow.of(2, 1, 3), GenericRow.of(3, 1, 4));
         List<InternalRow> expectedRow = new ArrayList<>();
         expectedRow.add(GenericRow.of(BinaryString.fromString("[1]"), 4L, 3L));
-        expectedRow.add(GenericRow.of(BinaryString.fromString("[2]"), 2L, 2L));
+        expectedRow.add(GenericRow.of(BinaryString.fromString("[2]"), 1L, 1L));
+        expectedRow.add(GenericRow.of(BinaryString.fromString("[3]"), 1L, 1L));
 
         List<InternalRow> result = read(partitionsTable, new int[][] {{0}, {1}, {3}});
         assertThat(result).containsExactlyInAnyOrderElementsOf(expectedRow);