feat: Add Databend connector

.github/workflows/ci.yml

@@ -350,6 +350,7 @@ jobs:
             !:trino-bigquery,
             !:trino-cassandra,
             !:trino-clickhouse,
+            !:trino-databend,
             !:trino-delta-lake,
             !:trino-docs,
             !:trino-druid,
@@ -480,6 +481,7 @@ jobs:
             - { modules: plugin/trino-bigquery, profile: cloud-tests-2 }
             - { modules: plugin/trino-cassandra }
             - { modules: plugin/trino-clickhouse }
+            - { modules: plugin/trino-databend }
             - { modules: plugin/trino-delta-lake }
             - { modules: plugin/trino-delta-lake, profile: cloud-tests }
             - { modules: plugin/trino-delta-lake, profile: fte-tests }

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

@@ -40,6 +40,12 @@
         </artifact>
     </artifactSet>
 
+    <artifactSet to="plugin/databend">
+        <artifact id="${project.groupId}:trino-databend:zip:${project.version}">
+            <unpack />
+        </artifact>
+    </artifactSet>
+
     <artifactSet to="plugin/delta-lake">
         <artifact id="${project.groupId}:trino-delta-lake:zip:${project.version}">
             <unpack />

docs/src/main/sphinx/connector.md

@@ -12,6 +12,7 @@ BigQuery        <connector/bigquery>
 Black Hole      <connector/blackhole>
 Cassandra       <connector/cassandra>
 ClickHouse      <connector/clickhouse>
+Databend        <connector/databend>
 Delta Lake      <connector/delta-lake>
 Druid           <connector/druid>
 DuckDB          <connector/duckdb>

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

@@ -0,0 +1,279 @@
+# Databend connector
+
+```{raw} html
+<img src="../_static/img/databend.png" class="connector-logo">
+```
+
+The Databend connector allows querying and creating tables in an external
+[Databend](https://databend.rs/) database. This can be used to join data between
+different systems like Databend and Hive, or between two different
+Databend instances.
+
+## Requirements
+
+To connect to Databend, you need:
+
+- Databend 1.2.0 or higher
+- Network access from the Trino coordinator and workers to Databend. Port 8000 is the default port.
+
+## Configuration
+
+To configure the Databend connector, create a catalog properties file
+in `etc/catalog` named, for example, `example.properties`, to
+mount the Databend connector as the `databend` catalog.
+Create the file with the following contents, replacing the
+connection properties as appropriate for your setup:
+
+```none
+connector.name=databend
+connection-url=jdbc:databend://host:8000/
+connection-user=root
+connection-password=
+```
+
+The `connection-url` defines the connection information and parameters to pass
+to the Databend JDBC driver. The supported parameters for the URL are
+available in the [Databend JDBC driver documentation](https://github.com/databendlabs/databend-jdbc).
+
+The `connection-user` and `connection-password` are typically required and
+determine the user credentials for the connection, often a service user. You can
+use {doc}`secrets </security/secrets>` to avoid actual values in the catalog
+properties files.
+
+### Multiple Databend databases
+
+The Databend connector can query multiple databases within a Databend instance.
+If you have multiple Databend instances, or want to connect to multiple
+catalogs in the same instance, configure another instance of the
+Databend connector as a separate catalog.
+
+### Connection security
+
+If you have TLS configured with a globally-trusted certificate installed on your
+data source, you can enable TLS between your cluster and the data
+source by appending the `ssl=true` parameter to the JDBC connection string set in the
+`connection-url` catalog configuration property.
+
+For example, with the Databend connector, enable TLS by appending the `ssl=true`
+parameter to the `connection-url` configuration property:
+
+```properties
+connection-url=jdbc:databend://host:8000/?ssl=true
+```
+
+For more information on TLS configuration options, see the
+[Databend JDBC driver documentation](https://github.com/databendlabs/databend-jdbc).
+
+```{include} jdbc-authentication.fragment
+```
+
+```{include} jdbc-kerberos.fragment
+```
+
+(databend-type-mapping)=
+## Type mapping
+
+Because Trino and Databend 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.
+
+### Databend type to Trino type mapping
+
+The connector maps Databend types to the corresponding Trino types following
+this table:
+
+:::{list-table} Databend type to Trino type mapping
+:widths: 30, 30, 40
+:header-rows: 1
+
+* - Databend type
+  - Trino type
+  - Notes
+* - `BOOLEAN`
+  - `BOOLEAN`
+  -
+* - `TINYINT`
+  - `TINYINT`
+  -
+* - `SMALLINT`
+  - `SMALLINT`
+  -
+* - `INTEGER`
+  - `INTEGER`
+  -
+* - `BIGINT`
+  - `BIGINT`
+  -
+* - `REAL`
+  - `REAL`
+  -
+* - `DOUBLE`
+  - `DOUBLE`
+  -
+* - `DECIMAL(p, s)`
+  - `DECIMAL(p, s)`
+  - See [](decimal-type-handling)
+* - `VARCHAR`
+  - `VARCHAR`
+  -
+* - `DATE`
+  - `DATE`
+  -
+* - `TIMESTAMP`
+  - `TIMESTAMP(0)`
+  - Databend TIMESTAMP is mapped to TIMESTAMP(0) in Trino
+:::
+
+No other types are supported.
+
+### Trino type to Databend type mapping
+
+The connector maps Trino types to the corresponding Databend types following
+this table:
+
+:::{list-table} Trino type to Databend type mapping
+:widths: 30, 30, 40
+:header-rows: 1
+
+* - Trino type
+  - Databend type
+  - Notes
+* - `BOOLEAN`
+  - `BOOLEAN`
+  -
+* - `TINYINT`
+  - `TINYINT`
+  -
+* - `SMALLINT`
+  - `SMALLINT`
+  -
+* - `INTEGER`
+  - `INTEGER`
+  -
+* - `BIGINT`
+  - `BIGINT`
+  -
+* - `REAL`
+  - `REAL`
+  -
+* - `DOUBLE`
+  - `DOUBLE`
+  -
+* - `DECIMAL(p, s)`
+  - `DECIMAL(p, s)`
+  -
+* - `CHAR(n)`
+  - `VARCHAR`
+  -
+* - `VARCHAR(n)`
+  - `VARCHAR`
+  -
+* - `VARBINARY`
+  - `VARCHAR`
+  -
+* - `DATE`
+  - `DATE`
+  -
+* - `TIMESTAMP(0)`
+  - `TIMESTAMP`
+  -
+:::
+
+No other types are supported.
+
+```{include} jdbc-type-mapping.fragment
+```
+
+(databend-sql-support)=
+## SQL support
+
+The connector provides read access and write access to data and metadata in
+a Databend 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/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`
+
+```{include} alter-table-limitation.fragment
+```
+
+```{include} alter-schema-limitation.fragment
+```
+
+### Procedures
+
+```{include} jdbc-procedures-flush.fragment
+```
+```{include} procedures-execute.fragment
+```
+
+### Table functions
+
+The connector provides specific [table functions](/functions/table) to
+access Databend.
+
+(databend-query-function)=
+#### `query(varchar) -> table`
+
+The `query` function allows you to query the underlying database directly. It
+requires syntax native to Databend, because the full query is pushed down and
+processed in Databend. 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.
+
+```{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
+```
+
+## Performance
+
+The connector includes a number of performance improvements, detailed in the
+following sections.
+
+(databend-pushdown)=
+### Pushdown
+
+The connector supports pushdown for a number of operations:
+
+- {ref}`limit-pushdown`
+
+{ref}`Aggregate pushdown <aggregation-pushdown>` for the following functions:
+
+- {func}`avg`
+- {func}`count`
+- {func}`max`
+- {func}`min`
+- {func}`sum`
+
+```{include} pushdown-correctness-behavior.fragment
+```
+
+```{include} no-inequality-pushdown-text-type.fragment
+```