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Add generated expression to extra info in Delta Lake #16631

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Merged
ebyhr merged 1 commit into from
Mar 20, 2023
Merged

Add generated expression to extra info in Delta Lake #16631

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12 changes: 8 additions & 4 deletions plugin/trino-delta-lake/src/main/java/io/trino/plugin/deltalake/DeltaLakeMetadata.java
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Original file line number Diff line number Diff line change
Expand Up @@ -452,12 +452,13 @@ public ConnectorTableMetadata getTableMetadata(ConnectorSession session, Connect
String location = metastore.getTableLocation(tableHandle.getSchemaTableName(), session);
Map<String, String> columnComments = getColumnComments(tableHandle.getMetadataEntry());
Map<String, Boolean> columnsNullability = getColumnsNullability(tableHandle.getMetadataEntry());
Map<String, String> columnGenerations = getGeneratedColumnExpressions(tableHandle.getMetadataEntry());
List<String> constraints = ImmutableList.<String>builder()
.addAll(getCheckConstraints(tableHandle.getMetadataEntry()).values())
.addAll(getColumnInvariants(tableHandle.getMetadataEntry()).values()) // The internal logic for column invariants in Delta Lake is same as check constraints
.build();
List<ColumnMetadata> columns = getColumns(tableHandle.getMetadataEntry()).stream()
.map(column -> getColumnMetadata(column, columnComments.get(column.getName()), columnsNullability.getOrDefault(column.getName(), true)))
.map(column -> getColumnMetadata(column, columnComments.get(column.getName()), columnsNullability.getOrDefault(column.getName(), true), columnGenerations.get(column.getName())))
.collect(toImmutableList());

ImmutableMap.Builder<String, Object> properties = ImmutableMap.<String, Object>builder()
Expand Down Expand Up @@ -507,7 +508,8 @@ public ColumnMetadata getColumnMetadata(ConnectorSession session, ConnectorTable
return getColumnMetadata(
column,
getColumnComments(table.getMetadataEntry()).get(column.getName()),
getColumnsNullability(table.getMetadataEntry()).getOrDefault(column.getName(), true));
getColumnsNullability(table.getMetadataEntry()).getOrDefault(column.getName(), true),
getGeneratedColumnExpressions(table.getMetadataEntry()).get(column.getName()));
}

/**
Expand Down Expand Up @@ -566,8 +568,9 @@ public Iterator<TableColumnsMetadata> streamTableColumns(ConnectorSession sessio
return metastore.getMetadata(metastore.getSnapshot(table, session), session).stream().map(metadata -> {
Map<String, String> columnComments = getColumnComments(metadata);
Map<String, Boolean> columnsNullability = getColumnsNullability(metadata);
Map<String, String> columnGenerations = getGeneratedColumnExpressions(metadata);
List<ColumnMetadata> columnMetadata = getColumns(metadata).stream()
.map(column -> getColumnMetadata(column, columnComments.get(column.getName()), columnsNullability.getOrDefault(column.getName(), true)))
.map(column -> getColumnMetadata(column, columnComments.get(column.getName()), columnsNullability.getOrDefault(column.getName(), true), columnGenerations.get(column.getName())))
.collect(toImmutableList());
return TableColumnsMetadata.forTable(table, columnMetadata);
});
Expand Down Expand Up @@ -2567,14 +2570,15 @@ private List<CommitInfoEntry> getCommitInfoEntries(SchemaTableName table, Connec
}
}

private static ColumnMetadata getColumnMetadata(DeltaLakeColumnHandle column, @Nullable String comment, boolean nullability)
private static ColumnMetadata getColumnMetadata(DeltaLakeColumnHandle column, @Nullable String comment, boolean nullability, @Nullable String generation)
{
return ColumnMetadata.builder()
.setName(column.getName())
.setType(column.getType())
.setHidden(column.getColumnType() == SYNTHESIZED)
.setComment(Optional.ofNullable(comment))
.setNullable(nullability)
.setExtraInfo(generation == null ? Optional.empty() : Optional.of("generated: " + generation))
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@ebyhr ebyhr Mar 20, 2023

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The expression may contain :. Do we want to just put generated without expression or quote the expression?

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@findepi findepi Mar 20, 2023 •
edited
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i think this is fine.

.build();
}

Expand Down
7 changes: 7 additions & 0 deletions .../src/main/java/io/trino/tests/product/deltalake/TestDeltaLakeAlterTableCompatibility.java
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Original file line number Diff line number Diff line change
Expand Up @@ -368,6 +368,13 @@ public void testTrinoAlterTablePreservesGeneratedColumn()
onDelta().executeQuery("INSERT INTO default." + tableName + " (a, c) VALUES (1, 3)");
assertThat(onTrino().executeQuery("SELECT * FROM delta.default." + tableName))
.containsOnly(row(1, 2, 3));

assertThat(onTrino().executeQuery("SELECT column_name, extra_info FROM delta.information_schema.columns WHERE table_schema = 'default' AND table_name = '" + tableName + "'"))
.containsOnly(row("a", null), row("b", "generated: a * 2"), row("c", null));
assertThat(onTrino().executeQuery("DESCRIBE delta.default." + tableName).project(1, 3))
.containsOnly(row("a", ""), row("b", "generated: a * 2"), row("c", ""));
assertThat(onTrino().executeQuery("SHOW COLUMNS FROM delta.default." + tableName).project(1, 3))
.containsOnly(row("a", ""), row("b", "generated: a * 2"), row("c", ""));
}
finally {
dropDeltaTableWithRetry("default." + tableName);
Expand Down