This change enables multiple datasources in Polaris, with possibility of **runtime** activation of the desired datasource.

This is achieved by:

1) Introducing a new enabler property: `polaris.persistence.relational.jdbc.datasource`, which points to a named datasource to activate.

2) Declaring, **at build time**, one named datasource for each JDBC driver shipped with the application.

3) Introducing a new `DataSourceActivator` config interceptor that will, at runtime, change the `active` setting of the target datasource to `true`, and all others to `false` (`active` is a runtime setting, contrary to `db-kind`).

This change also makes the server ship with the H2 driver by default, since that's the pre-condition for an H2 datasource to be selected at runtime.

This change will further enable **as future improvements**:

- Using to JDBC + H2 by default for server images, while still allowing users to switch to PostgreSQL *without having to rebuild Polaris*.

- Enabling the persistence to "plug" into not one, but many datasources, e.g. a specific datasource for main persistence, and a separate datasource for metrics. This was outlined in apache#3960 – but the machinery to make that happen was missing.

Author: adutra

persistence/relational-jdbc/src/main/java/org/apache/polaris/persistence/relational/jdbc/JdbcMetaStoreManagerFactory.java

@@ -22,8 +22,6 @@
 
 import io.smallrye.common.annotation.Identifier;
 import jakarta.enterprise.context.ApplicationScoped;
-import jakarta.enterprise.inject.Instance;
-import jakarta.enterprise.inject.Produces;
 import jakarta.inject.Inject;
 import java.sql.SQLException;
 import java.time.Clock;
@@ -32,7 +30,6 @@
 import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
-import javax.sql.DataSource;
 import org.apache.polaris.core.PolarisCallContext;
 import org.apache.polaris.core.PolarisDiagnostics;
 import org.apache.polaris.core.config.BehaviorChangeConfiguration;
@@ -93,13 +90,6 @@ public class JdbcMetaStoreManagerFactory implements MetaStoreManagerFactory {
 
   protected JdbcMetaStoreManagerFactory() {}
 
-  @Produces
-  @ApplicationScoped
-  static DatasourceOperations produceDatasourceOperations(
-      Instance<DataSource> dataSource, RelationalJdbcConfiguration relationalJdbcConfiguration) {
-    return new DatasourceOperations(dataSource.get(), relationalJdbcConfiguration);
-  }
-
   protected PrincipalSecretsGenerator secretsGenerator(
       String realmId, @Nullable RootCredentialsSet rootCredentialsSet) {
     if (rootCredentialsSet != null) {

persistence/relational-jdbc/src/main/java/org/apache/polaris/persistence/relational/jdbc/RelationalJdbcConfiguration.java

@@ -21,18 +21,21 @@
 import java.util.Optional;
 
 public interface RelationalJdbcConfiguration {
-  // max retries before giving up
+  /** The maximum number of retries before giving up the operation. */
   Optional<Integer> maxRetries();
 
-  // max retry duration
+  /** The maximum retry duration in milliseconds. */
   Optional<Long> maxDurationInMs();
 
-  // initial delay
+  /** The initial retry delay. */
   Optional<Long> initialDelayInMs();
 
   /**
    * Explicitly configured database type. If not specified, the database type will be inferred from
    * the JDBC connection metadata. Supported values: "postgresql", "cockroachdb", "h2"
    */
   Optional<String> databaseType();
+
+  /** The datasource name to use. Required. */
+  String dataSource();
 }

persistence/relational-jdbc/src/main/java/org/apache/polaris/persistence/relational/jdbc/RelationalJdbcProductionReadinessChecks.java

@@ -40,7 +40,7 @@ public ProductionReadinessCheck checkRelationalJdbc(
       return ProductionReadinessCheck.of(
           ProductionReadinessCheck.Error.of(
               "The current persistence (jdbc:h2) is intended for tests only.",
-              "quarkus.datasource.jdbc.url"));
+              "polaris.persistence.relational.jdbc.datasource"));
     }
     return ProductionReadinessCheck.OK;
   }

persistence/relational-jdbc/src/test/java/org/apache/polaris/persistence/relational/jdbc/JdbcGrantRecordsIdempotencyTest.java

@@ -154,5 +154,10 @@ public Optional<Long> initialDelayInMs() {
     public Optional<String> databaseType() {
       return Optional.of("h2");
     }
+
+    @Override
+    public String dataSource() {
+      return "h2";
+    }
   }
 }

persistence/relational-jdbc/src/test/java/org/apache/polaris/persistence/relational/jdbc/MetricsReportPersistenceTest.java

@@ -202,5 +202,10 @@ public Optional<Long> initialDelayInMs() {
     public Optional<String> databaseType() {
       return Optional.empty();
     }
+
+    @Override
+    public String dataSource() {
+      return "h2";
+    }
   }
 }

persistence/relational-jdbc/src/test/java/org/apache/polaris/persistence/relational/jdbc/RelationalJdbcProductionReadinessChecksTest.java

@@ -72,7 +72,8 @@ void jdbcWithH2ReturnsWarning() {
             error -> {
               assertThat(error.message())
                   .isEqualTo("The current persistence (jdbc:h2) is intended for tests only.");
-              assertThat(error.offendingProperty()).isEqualTo("quarkus.datasource.jdbc.url");
+              assertThat(error.offendingProperty())
+                  .isEqualTo("polaris.persistence.relational.jdbc.datasource");
               assertThat(error.severe()).isFalse();
             });
   }

persistence/relational-jdbc/src/test/java/org/apache/polaris/persistence/relational/jdbc/SimpleRelationalJdbcConfiguration.java

@@ -56,4 +56,10 @@ public Optional<Long> initialDelayInMs() {
   public Optional<String> databaseType() {
     return Optional.of(databaseType);
   }
+
+  @Override
+  public String dataSource() {
+    // The datasource name is irrelevant for tests that do not leverage CDI
+    return "datasource1";
+  }
 }

persistence/relational-jdbc/src/test/java/org/apache/polaris/persistence/relational/jdbc/idempotency/RelationalJdbcIdempotencyStorePostgresIT.java

@@ -82,6 +82,11 @@ public Optional<Long> initialDelayInMs() {
           public Optional<String> databaseType() {
             return Optional.empty();
           }
+
+          @Override
+          public String dataSource() {
+            return "postgres";
+          }
         };
     DatasourceOperations ops = new DatasourceOperations(dataSource, cfg);
     try (InputStream is =

runtime/admin/build.gradle.kts

@@ -33,9 +33,13 @@ dependencies {
 
   compileOnly("com.fasterxml.jackson.core:jackson-annotations")
 
+  implementation(enforcedPlatform(libs.quarkus.bom))
+
+  // JDBC persistence + backends
   runtimeOnly(project(":polaris-relational-jdbc"))
-  runtimeOnly("org.postgresql:postgresql")
+  runtimeOnly("io.quarkus:quarkus-jdbc-postgresql")
 
+  // NoSQL persistence + backends
   implementation(project(":polaris-persistence-nosql-api"))
   implementation(project(":polaris-persistence-nosql-maintenance-api"))
   runtimeOnly(project(":polaris-persistence-nosql-metastore"))
@@ -46,8 +50,6 @@ dependencies {
 
   runtimeOnly("io.quarkus:quarkus-mongodb-client")
 
-  implementation("io.quarkus:quarkus-jdbc-postgresql")
-  implementation(enforcedPlatform(libs.quarkus.bom))
   implementation("io.quarkus:quarkus-picocli")
   implementation("io.quarkus:quarkus-container-image-docker")
 

runtime/admin/src/main/resources/application.properties

@@ -31,7 +31,12 @@ quarkus.container-image.registry=docker.io
 quarkus.container-image.group=apache
 quarkus.container-image.name=polaris-admin-tool
 quarkus.container-image.additional-tags=latest
-quarkus.datasource.db-kind=postgresql
+
+# Named datasources for relational persistence backends.
+# Polaris ships with many built-in datasources; by using named datasources, users can configure
+# at runtime which datasources to use for relational persistence backends.
+quarkus.datasource.postgresql.db-kind=postgresql
+
 # if set to true it will try to start localstack at build and run time for the local environment
 # https://docs.quarkiverse.io/quarkus-amazon-services/dev/amazon-rds.html#_configuration_reference for more details
 quarkus.rds.devservices.enabled=false
@@ -41,12 +46,13 @@ quarkus.mongodb.devservices.enabled=false
 # ---- Runtime Configuration ----
 # Below are default values for properties that can be changed in runtime.
 
-# Available types:
+# Polaris persistence type. Available types:
 # - in-memory - InMemoryPolarisMetaStoreManagerFactory
 # - in-memory-atomic - InMemoryAtomicOperationMetaStoreManagerFactory
-# - relational-jdbc - JdbcMetaStoreManagerFactory
-# - nosql - NoSQL persistence backend, define the backend type via 'polaris.persistence.nosql.backend'
+# - nosql (beta) - NoSQL persistence backend, define the backend type via 'polaris.persistence.nosql.backend'
+# - relational-jdbc - JDBC persistence backend, define the JDBC datasource via 'polaris.persistence.relational.jdbc.datasource' and 'quarkus.datasource.<datasource-name>.*'
 polaris.persistence.type=relational-jdbc
+
 # Database backend for 'nosql' persistence-type
 # Available backends:
 # - InMemory - for testing purposes
@@ -55,6 +61,21 @@ polaris.persistence.type=relational-jdbc
 #     See https://quarkus.io/guides/mongodb#configuration-reference for details about these configurations.
 #polaris.persistence.nosql.backend=InMemory
 
+# Datasource to activate for the 'relational-jdbc' persistence type.
+# Built-in supported datasources:
+# - postgresql - activates the PostgreSQL datasource (default)
+#     Configure the necessary PostgreSQL properties starting with 'quarkus.datasource.postgresql.' in this file (see below).
+# See https://quarkus.io/guides/datasource#configuration-reference for details about these configurations.
+# Please do NOT set quarkus.datasource.active manually, Polaris will set it automatically based on
+# this property.
+polaris.persistence.relational.jdbc.datasource=postgresql
+
+# Postgres datasource configuration:
+quarkus.datasource.postgresql.devservices.enabled=false
+#quarkus.datasource.postgresql.jdbc.url=jdbc:postgresql://localhost:5432/my_database
+#quarkus.datasource.postgresql.username=<your username>
+#quarkus.datasource.postgresql.password=<your password>
+
 ## MongoDB version store specific configuration
 #quarkus.mongodb.database=polaris
 #quarkus.mongodb.metrics.enabled=true