Add DuckDB connector

.github/workflows/ci.yml

@@ -341,6 +341,7 @@ jobs:
             !:trino-delta-lake,
             !:trino-docs,
             !:trino-druid,
+            !:trino-duckdb,
             !:trino-elasticsearch,
             !:trino-exasol,
             !:trino-faulttolerant-tests,
@@ -452,6 +453,7 @@ jobs:
             - { modules: plugin/trino-delta-lake, profile: cloud-tests }
             - { modules: plugin/trino-delta-lake, profile: fte-tests }
             - { modules: plugin/trino-druid }
+            - { modules: plugin/trino-duckdb }
             - { modules: plugin/trino-elasticsearch }
             - { modules: plugin/trino-exasol }
             - { modules: plugin/trino-google-sheets }

core/trino-server/src/main/provisio/trino.xml

@@ -78,6 +78,12 @@
         </artifact>
     </artifactSet>
 
+    <artifactSet to="plugin/duckdb">
+        <artifact id="${project.groupId}:trino-duckdb:zip:${project.version}">
+            <unpack />
+        </artifact>
+    </artifactSet>
+
     <artifactSet to="plugin/elasticsearch">
         <artifact id="${project.groupId}:trino-elasticsearch:zip:${project.version}">
             <unpack />

docs/src/main/sphinx/connector.md

@@ -15,6 +15,7 @@ Cassandra       <connector/cassandra>
 ClickHouse      <connector/clickhouse>
 Delta Lake      <connector/delta-lake>
 Druid           <connector/druid>
+DuckDB          <connector/duckdb>
 Elasticsearch   <connector/elasticsearch>
 Exasol          <connector/exasol>
 Google Sheets   <connector/googlesheets>

docs/src/main/sphinx/connector/duckdb.md

@@ -0,0 +1,207 @@
+# DuckDB connector
+
+```{raw} html
+<img src="../_static/img/duckdb.png" class="connector-logo">
+```
+
+The DuckDB connector allows querying and creating tables in an external
+[DuckDB](https://duckdb.org/) instance. This can be used to join data between
+different systems like DuckDB and Hive, or between two different
+DuckDB instances.
+
+## Configuration
+
+To configure the DuckDB connector, create a catalog properties file
+in `etc/catalog` named, for example, `example.properties`, to
+mount the DuckDB connector as the `duckdb` catalog.
+Create the file with the following contents, replacing the
+connection properties as appropriate for your setup:
+
+```none
+connector.name=duckdb
+connection-url=jdbc:duckdb://<path>
+connection-user=root
+connection-password=secret
+```
+
+### Multiple DuckDB servers
+
+The DuckDB connector can only access a single database within
+a DuckDB instance. Thus, if you have multiple DuckDB servers,
+or want to connect to multiple DuckDB servers, you must configure
+multiple instances of the DuckDB connector.
+
+(duckdb-type-mapping)=
+## Type mapping
+
+Because Trino and DuckDB each support types that the other does not, this
+connector {ref}`modifies some types <type-mapping-overview>` when reading or
+writing data. Data types may not map the same way in both directions between
+Trino and the data source. Refer to the following sections for type mapping in
+each direction.
+
+List of [DuckDB data types](https://duckdb.org/docs/sql/data_types/overview.html).
+
+### DuckDB type to Trino type mapping
+
+The connector maps DuckDB types to the corresponding Trino types following
+this table:
+
+:::{list-table} DuckDB type to Trino type mapping
+:widths: 30, 30, 40
+:header-rows: 1
+
+* - DuckDB type
+  - Trino type
+  - Notes
+* - `BOOLEAN`
+  - `BOOLEAN`
+  -
+* - `TINYINT`
+  - `TINYINT`
+  - 
+* - `SMALLINT`
+  - `SMALLINT`
+  - 
+* - `INTEGER`
+  - `INTEGER`
+  - 
+* - `BIGINT`
+  - `BIGINT`
+  - 
+* - `FLOAT`
+  - `REAL`
+  - 
+* - `DOUBLE`
+  - `DOUBLE`
+  - 
+* - `DECIMAL`
+  - `DECIMAL`
+  - Default precision and scale are (18,3).
+* - `VARCHAR`
+  - `VARCHAR`
+  -
+* - `DATE`
+  - `DATE`
+  -
+:::
+
+No other types are supported.
+
+### Trino type to DuckDB type mapping
+
+The connector maps Trino types to the corresponding DuckDB types following
+this table:
+
+:::{list-table} Trino type to DuckDB type mapping
+:widths: 30, 30, 40
+:header-rows: 1
+
+* - Trino type
+  - DuckDB type
+  - Notes
+* - `BOOLEAN`
+  - `BOOLEAN`
+  -
+* - `TINYINT`
+  - `TINYINT`
+  -
+* - `SMALLINT`
+  - `SMALLINT`
+  -
+* - `INTEGER`
+  - `INTEGER`
+  -
+* - `BIGINT`
+  - `BIGINT`
+  -
+* - `REAL`
+  - `REAL`
+  -
+* - `DOUBLE`
+  - `DOUBLE`
+  -
+* - `DECIMAL`
+  - `DECIMAL`
+  -
+* - `CHAR`
+  - `VARCHAR`
+  -
+* - `VARCHAR`
+  - `VARCHAR`
+  -
+* - `DATE`
+  - `DATE`
+  -
+:::
+
+No other types are supported.
+
+```{include} jdbc-type-mapping.fragment
+```
+
+(duckdb-sql-support)=
+## SQL support
+
+The connector provides read access and write access to data and metadata in
+a DuckDB database.  In addition to the {ref}`globally available
+<sql-globally-available>` and {ref}`read operation <sql-read-operations>`
+statements, the connector supports the following features:
+
+- {doc}`/sql/insert`
+- {doc}`/sql/delete`
+- {doc}`/sql/truncate`
+- {doc}`/sql/create-table`
+- {doc}`/sql/create-table-as`
+- {doc}`/sql/drop-table`
+- {doc}`/sql/alter-table`
+- {doc}`/sql/create-schema`
+- {doc}`/sql/drop-schema`
+
+### Procedures
+
+```{include} jdbc-procedures-flush.fragment
+```
+```{include} procedures-execute.fragment
+```
+
+### Table functions
+
+The connector provides specific [table functions](/functions/table) to
+access DuckDB.
+
+(duckdb-query-function)=
+#### `query(varchar) -> table`
+
+The `query` function allows you to query the underlying database directly. It
+requires syntax native to DuckDB, because the full query is pushed down and
+processed in DuckDB. This can be useful for accessing native features which
+are not available in Trino or for improving query performance in situations
+where running a query natively may be faster.
+
+Find details about the SQL support of DuckDB that you can use in the query in
+the [DuckDB SQL Command
+Reference](https://duckdb.org/docs/sql/query_syntax/select) and
+other statements and functions.
+
+```{include} query-passthrough-warning.fragment
+```
+
+As a simple example, query the `example` catalog and select an entire table:
+
+```
+SELECT
+  *
+FROM
+  TABLE(
+    example.system.query(
+      query => 'SELECT
+        *
+      FROM
+        tpch.nation'
+    )
+  );
+```
+
+```{include} query-table-function-ordering.fragment
+```

plugin/trino-base-jdbc/src/test/java/io/trino/plugin/jdbc/BaseCaseInsensitiveMappingTest.java

@@ -261,7 +261,8 @@ public void testTableNameRuleMapping()
                 AutoCloseable ignore1 = withTable(schema, "remote_table", "(c varchar(5))")) {
             assertThat(computeActual("SHOW TABLES FROM " + schema).getOnlyColumn())
                     .contains("trino_table");
-            assertQuery("SHOW COLUMNS FROM " + schema + ".trino_table", "SELECT 'c', 'varchar(5)', '', ''");
+            assertThat(query("SHOW COLUMNS FROM " + schema + ".trino_table")).result().projected("Column").onlyColumnAsSet()
+                    .contains("c");
             assertUpdate("INSERT INTO " + schema + ".trino_table VALUES 'dane'", 1);
             assertQuery("SELECT * FROM " + schema + ".trino_table", "VALUES 'dane'");
         }
@@ -324,7 +325,8 @@ public void testSchemaAndTableNameRuleMapping()
                     .contains("trino_schema");
             assertThat(computeActual("SHOW TABLES IN trino_schema").getOnlyColumn())
                     .contains("trino_table");
-            assertQuery("SHOW COLUMNS FROM trino_schema.trino_table", "SELECT 'c', 'varchar(5)', '', ''");
+            assertThat(query("SHOW COLUMNS FROM trino_schema.trino_table")).result().projected("Column").onlyColumnAsSet()
+                    .contains("c");
             assertUpdate("INSERT INTO trino_schema.trino_table VALUES 'dane'", 1);
             assertQuery("SELECT * FROM trino_schema.trino_table", "VALUES 'dane'");
         }