Fix failure when reading deep or shallow cloned Delta Lake tables #27098

yangshangqing95 · 2025-10-25T03:44:09Z

Description

For cloned Delta Lake tables (either deep or shallow clones), the checkpoint version may start at 0.
The previous validation in the CheckpointMetadataEntry constructor required the version to be positive,
which caused the following exception:

Query xxxx failed: Unable to parse transaction log entry: {"checkpointMetadata":{"version":0, ....}}

Root cause is:

com.fasterxml.jackson.databind.exc.ValueInstantiationException: 
Cannot construct instance of `io.trino.plugin.deltalake.transactionlog.CheckpointMetadataEntry`,
problem: version is not positive: 0

Additional context and related issues

Fixes #27097

Release notes

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## Section
* Fix failure when reading deep or shallow cloned Delta Lake tables with checkpoint version 0.

Summary by Sourcery

Allow checkpoint metadata version zero for Delta Lake clones and add comprehensive tests for CheckpointMetadataEntry.

Bug Fixes:

Relax the version validation in CheckpointMetadataEntry to accept zero instead of requiring positive values

Enhancements:

Change the version check from > 0 to >= 0 to support deep and shallow cloned Delta Lake tables

Tests:

Add TestCheckpointMetadataEntry to verify JSON serialization/deserialization and validation for versions 0, positive, and negative

sourcery-ai · 2025-10-25T03:44:15Z

Reviewer's Guide

This PR adjusts the checkpoint metadata validation to accept version 0 on Delta Lake table clones and supplements it with comprehensive unit tests covering valid, zero, and negative version scenarios as well as JSON serialization.

Class diagram for updated CheckpointMetadataEntry validation

classDiagram
    class CheckpointMetadataEntry {
        +long version
        +Optional<Map<String, String>> tags
        +CheckpointMetadataEntry(long version, Optional<Map<String, String>> tags)
    }
    CheckpointMetadataEntry : version >= 0 validation
    CheckpointMetadataEntry : tags are copied as ImmutableMap

Class diagram for new TestCheckpointMetadataEntry unit tests

classDiagram
    class TestCheckpointMetadataEntry {
        +testValidVersion()
        +testZeroVersion()
        +testNegativeVersionThrows()
        +testJsonSerialization()
    }
    TestCheckpointMetadataEntry --> CheckpointMetadataEntry

File-Level Changes

Change	Details	Files
Relax version validation in CheckpointMetadataEntry to accept version 0	Change precondition from version > 0 to version >= 0 Update validation error message to reflect only negative versions	`plugin/trino-delta-lake/src/main/java/io/trino/plugin/deltalake/transactionlog/CheckpointMetadataEntry.java`
Add unit tests covering boundary cases for checkpoint metadata	Test deserialization with version 0 alongside existing positive cases Verify failure on negative version and missing tags Test JSON serialization output formatting	`plugin/trino-delta-lake/src/test/java/io/trino/plugin/deltalake/transactionlog/TestCheckpointMetadataEntry.java`

Possibly linked issues

Failure when reading deep or shallow cloned Delta Lake tables #27097: The PR fixes the issue by allowing checkpoint version 0 in Delta Lake tables, resolving the transaction log parsing exception.

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sourcery-ai

Hey there - I've reviewed your changes and they look great!

Prompt for AI Agents

Please address the comments from this code review:

## Individual Comments

### Comment 1
<location> `plugin/trino-delta-lake/src/test/java/io/trino/plugin/deltalake/transactionlog/TestCheckpointMetadataEntry.java:55-64` </location>
<code_context>
+    }
+
+    @Test
+    void testInvalidCheckpointMetadataEntry()
+    {
+        @Language("JSON")
+        String jsonWithNegativeVersion = "{\"version\":-1,\"tags\":{\"sidecarNumActions\":\"1\",\"sidecarSizeInBytes\":\"20965\",\"numOfAddFiles\":\"1\",\"sidecarFileSchema\":\"\"}}";
+        assertThatThrownBy(() -> codec.fromJson(jsonWithNegativeVersion))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessageContaining("Invalid JSON string for");
+
+        @Language("JSON")
+        String jsonWithoutTags = "{\"version\":-1}";
+        assertThatThrownBy(() -> codec.fromJson(jsonWithoutTags))
+                .isInstanceOf(IllegalArgumentException.class)
</code_context>

<issue_to_address>
**suggestion (testing):** Missing test for valid CheckpointMetadataEntry with absent 'tags' field.

Please add a test for deserializing a valid CheckpointMetadataEntry with a non-negative version and no 'tags' field to confirm correct handling of this case.
</issue_to_address>

### Comment 2
<location> `plugin/trino-delta-lake/src/test/java/io/trino/plugin/deltalake/transactionlog/TestCheckpointMetadataEntry.java:70-89` </location>
<code_context>
+    }
+
+    @Test
+    void testCheckpointMetadataEntryToJson()
+    {
+        assertThat(codec.toJson(new CheckpointMetadataEntry(
+                100,
+                Optional.of(ImmutableMap.of(
+                        "sidecarNumActions", "1",
+                        "sidecarSizeInBytes", "20965",
+                        "numOfAddFiles", "1",
+                        "sidecarFileSchema", "")))))
+                .isEqualTo("{\n" +
+                        "  \"version\" : 100,\n" +
+                        "  \"tags\" : {\n" +
+                        "    \"sidecarNumActions\" : \"1\",\n" +
+                        "    \"sidecarSizeInBytes\" : \"20965\",\n" +
+                        "    \"numOfAddFiles\" : \"1\",\n" +
+                        "    \"sidecarFileSchema\" : \"\"\n" +
+                        "  }\n" +
+                        "}");
+    }
</code_context>

<issue_to_address>
**suggestion (testing):** Consider adding a test for serialization with version 0 and absent 'tags'.

Please add a test case for serializing a CheckpointMetadataEntry with version 0 and no 'tags', and verify the resulting JSON structure.

```suggestion
    @Test
    void testCheckpointMetadataEntryToJson()
    {
        assertThat(codec.toJson(new CheckpointMetadataEntry(
                100,
                Optional.of(ImmutableMap.of(
                        "sidecarNumActions", "1",
                        "sidecarSizeInBytes", "20965",
                        "numOfAddFiles", "1",
                        "sidecarFileSchema", "")))))
                .isEqualTo("{\n" +
                        "  \"version\" : 100,\n" +
                        "  \"tags\" : {\n" +
                        "    \"sidecarNumActions\" : \"1\",\n" +
                        "    \"sidecarSizeInBytes\" : \"20965\",\n" +
                        "    \"numOfAddFiles\" : \"1\",\n" +
                        "    \"sidecarFileSchema\" : \"\"\n" +
                        "  }\n" +
                        "}");
    }

    @Test
    void testCheckpointMetadataEntryToJsonWithVersionZeroAndNoTags()
    {
        assertThat(codec.toJson(new CheckpointMetadataEntry(
                0,
                Optional.empty())))
                .isEqualTo("{\n" +
                        "  \"version\" : 0\n" +
                        "}");
    }
```
</issue_to_address>

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...lake/src/test/java/io/trino/plugin/deltalake/transactionlog/TestCheckpointMetadataEntry.java

ebyhr · 2025-10-25T03:53:59Z

...lake/src/test/java/io/trino/plugin/deltalake/transactionlog/TestCheckpointMetadataEntry.java

@@ -0,0 +1,90 @@
+/*


We prefer query based tests to unit tests in this repository.
Please update existing integration tests or product tests instead.

Sure, integration tests updated

ebyhr · 2025-10-25T03:55:49Z

Fix failure when reading deep or shallow cloned Delta Lake tables.

https://trino.io/development/process#pull-request-and-commit-guidelines

Do not end the subject line with a period.

yangshangqing95 · 2025-10-26T00:32:41Z

Fix failure when reading deep or shallow cloned Delta Lake tables.

https://trino.io/development/process#pull-request-and-commit-guidelines

Do not end the subject line with a period.

Fixed

chenjian2664 · 2025-10-26T00:52:32Z

plugin/trino-delta-lake/src/test/java/io/trino/plugin/deltalake/TestDeltaLakeBasic.java

+            throws Exception
+    {
+        testClonedTableWithCheckpointVersionZero("databricks154/clone_checkpoint_version_zero/checkpoint_v1/clone_source");
+        testClonedTableWithCheckpointVersionZero("databricks154/clone_checkpoint_version_zero/checkpoint_v2/cloned_table");


typo, should be databricks154/clone_checkpoint_version_zero/checkpoint_v1/cloned_table ?

Yes thanks! fixed

chenjian2664 · 2025-10-26T00:55:44Z

plugin/trino-delta-lake/src/test/java/io/trino/plugin/deltalake/TestDeltaLakeBasic.java

+    {
+        testClonedTableWithCheckpointVersionZero("databricks154/clone_checkpoint_version_zero/checkpoint_v1/clone_source");
+        testClonedTableWithCheckpointVersionZero("databricks154/clone_checkpoint_version_zero/checkpoint_v2/cloned_table");
+        testClonedTableWithCheckpointVersionZero("databricks154/clone_checkpoint_version_zero/checkpoint_v2/clone_source");


I think we could remove source table, test cloned source is enough

just test on my local, seems v1 test case not exercise the logic

Yeah that make sense, as the v1 checkpoint file is in Parquet format, so it won’t go through this JSON deserialization logic. I was just testing v1 incidentally to see if there were any issues. If it’s not needed, I can remove it.

I think we may just keep it, there’s no harm in it.

There is no necessary to add v1 case here, since CheckpointMetadata only allowed in v2 spec https://github.com/delta-io/delta/blob/master/PROTOCOL.md#checkpoint-metadata

sure, updated

chenjian2664 · 2025-10-29T00:23:25Z

Fix failure when reading deep or shallow cloned Delta Lake tables.

https://trino.io/development/process#pull-request-and-commit-guidelines

Do not end the subject line with a period.

reminder

chenjian2664

Looks good

chenjian2664 · 2025-10-29T00:27:39Z

plugin/trino-delta-lake/src/test/java/io/trino/plugin/deltalake/TestDeltaLakeBasic.java

+        copyDirectoryContents(new File(Resources.getResource(resourceName).toURI()).toPath(), tableLocation);
+        assertUpdate("CALL system.register_table(CURRENT_SCHEMA, '%s', '%s')".formatted(tableName, tableLocation.toUri()));
+
+        assertThat(query("SELECT * FROM " + tableName + " ORDER BY id")).matches("VALUES " +


nit: move .matches to new line

chenjian2664 · 2025-10-29T00:29:32Z

plugin/trino-delta-lake/src/test/java/io/trino/plugin/deltalake/TestDeltaLakeBasic.java

+        testClonedTableWithCheckpointVersionZero("databricks154/clone_checkpoint_version_zero/checkpoint_v2/cloned_table");
+    }
+
+    private void testClonedTableWithCheckpointVersionZero(String resourceName)


now seems the the method is redundant, we could remove it, put code under testClonedTableWithCheckpointVersionZero()

chenjian2664 · 2025-10-31T01:12:24Z

...t/resources/databricks154/clone_checkpoint_version_zero/checkpoint_v2/cloned_table/README.md

+Data generated using Databricks 15.4:
+
+```sql
+CREATE TABLE cloned_table DEEP CLONE source_table;


Can we also add a case for shallow clone?

Maybe no need for that? as the only difference is the flag isShallow for true or false in the transaction log.

cla-bot bot added the cla-signed label Oct 25, 2025

github-actions bot added the delta-lake Delta Lake connector label Oct 25, 2025

sourcery-ai bot reviewed Oct 25, 2025

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...lake/src/test/java/io/trino/plugin/deltalake/transactionlog/TestCheckpointMetadataEntry.java Show resolved Hide resolved

ebyhr reviewed Oct 25, 2025

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yangshangqing95 changed the title ~~Fix failure when reading deep or shallow cloned Delta Lake tables.~~ Fix failure when reading deep or shallow cloned Delta Lake tables Oct 25, 2025

yangshangqing95 force-pushed the fix-read-cloned-delta-lake-table-error branch from 14dd843 to d1593a9 Compare October 26, 2025 00:31

chenjian2664 reviewed Oct 26, 2025

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yangshangqing95 force-pushed the fix-read-cloned-delta-lake-table-error branch 2 times, most recently from 199baac to 3be6244 Compare October 28, 2025 15:49

chenjian2664 approved these changes Oct 29, 2025

View reviewed changes

Fix failure when reading deep or shallow cloned Delta Lake tables.

78997c3

yangshangqing95 force-pushed the fix-read-cloned-delta-lake-table-error branch from 3be6244 to 78997c3 Compare October 29, 2025 14:25

chenjian2664 reviewed Oct 31, 2025

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Fix failure when reading deep or shallow cloned Delta Lake tables #27098

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Fix failure when reading deep or shallow cloned Delta Lake tables #27098

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Description

Additional context and related issues

Release notes

Summary by Sourcery

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Reviewer's Guide

Class diagram for updated CheckpointMetadataEntry validation

Class diagram for new TestCheckpointMetadataEntry unit tests

File-Level Changes

Possibly linked issues

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yangshangqing95 commented Oct 25, 2025 •

edited by ebyhr

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