[jdbc-v2] `DataLakeCatalog` is not present in `getSchemas()` result or avoid using `system.*` where possible.

从 JDBC DatabaseMetaData getSchemas() 和 getTables() 入口点开始，在使用 DataLakeCatalog 引擎的数据库上复现该问题。将当前的 system.databases 查询与 SHOW DATABASES 进行比较，并验证涉及 DataLakeCatalog 的元数据调用不会产生文档中说明的访问错误；当预期的选项或行为已由测试覆盖时，该 issue 即完成。

Description

Databases with engine DataLakeCatalog are not visible when requested via DataBaseMetadata because driver uses system.databases to fetch this information.

Workaround: show_data_lake_catalogs_in_system_tables=1 settings in session or profile.

Note

As SHOW DATABASES return better information - JDBC Driver should make it at least an option.

DBeaver and Metabase

When workaround applied these products getting exception trying to read tables information.
See https://clickhouse.com/docs/operations/settings/settings#database_datalake_require_metadata_access

2026-07-02T21:19:42+02:00 ERROR metabase.sync.fetch-metadata Error while fetching metadata with 'db-metadata',java.sql.SQLException: Code: 736. DB::Exception: Received error 736 while fetching table metadata for existing table 'product_analyst_team.vw_ap_integrations_2026'. If you want this error to be ignored, use database_datalake_require_metadata_access=0. Error: Code: 736. DB::Exception: Cannot read table `sandbox.product_analyst_team.vw_ap_integrations_2026` because it doesn't have storage location. It means that it's not a DeltaLake table, and it's unreadable with Unity catalog in ClickHouse. (...,	at com.clickhouse.jdbc.internal.ExceptionUtils.toSqlState(ExceptionUtils.java:68),	at com.clickhouse.jdbc.internal.ExceptionUtils.toSqlState(ExceptionUtils.java:43),	at com.clickhouse.jdbc.StatementImpl.executeQueryImpl(StatementImpl.java:196),	at com.clickhouse.jdbc.PreparedStatementImpl.executeQuery(PreparedStatementImpl.java:138),	at com.clickhouse.jdbc.metadata.DatabaseMetaDataImpl.getTables(DatabaseMetaDataImpl.java:998),	at com.mchange.v2.c3p0.impl.NewProxyDatabaseMetaData.getTables(NewProxyDatabaseMetaData.java:4174),	at metabase.driver.clickhouse_introspection$get_tables_from_metadata.invokeStatic(clickhouse_introspection.clj:109),	at metabase.driver.clickhouse_introspection$get_tables_from_metadata.invoke(clickhouse_introspection.clj:107),	at metabase.driver.clickhouse_introspection$get_all_tables_in_all_dbs$fn__173063.invoke(clickhouse_introspection.clj:128),	at metabase.driver.clickhouse$fn__173529$fn__173531.invoke(clickhouse.clj:102),	at metabase.driver.sql_jdbc.execute$do_with_resolved_connection.invokeStatic(execute.clj:366),	at metabase.driver.sql_jdbc.execute$do_with_resolved_connection.invoke(execute.clj:338),	at metabase.driver.clickhouse$fn__173529.invokeStatic(clickhouse.clj:79),	at metabase.driver.clickhouse$fn__173529.invoke(clickhouse.clj:77),	at clojure.lang.MultiFn.invoke(MultiFn.java:244),	at metabase.driver.clickhouse_introspection$get_all_tables_in_all_dbs.invokeStatic(clickhouse_introspection.clj:125),	at metabase.driver.clickhouse_introspection$get_all_tables_in_all_dbs.invoke(clickhouse_introspection.clj:119),	at metabase.driver.clickhouse_introspection$fn__173076.invokeStatic(clickhouse_introspection.clj:170),	at metabase.driver.clickhouse_introspection$fn__173076.invoke(clickhouse_introspection.clj:166)
2026-07-02T21:19:42+02:00 WARN metabase.sync.util Error in sync step Sync metadata for clickhouse Database 43 ''test-clickhouse-cloud'',java.sql.SQLException: Code: 736. DB::Exception: Received error 736 while fetching table metadata for existing table 'product_analyst_team.vw_ap_integrations_2026'. If you want this error to be ignored, use database_datalake_require_metadata_access=0. Error: Code: 736. DB::Exception: Cannot read table `sandbox.product_analyst_team.vw_ap_integrations_2026` because it doesn't have storage location. It means that it's not a DeltaLake table, and it's unreadable with Unity catalog in ClickHouse. (...,	at com.clickhouse.jdbc.internal.ExceptionUtils.toSqlState(ExceptionUtils.java:68),	at com.clickhouse.jdbc.internal.ExceptionUtils.toSqlState(ExceptionUtils.java:43),	at com.clickhouse.jdbc.StatementImpl.executeQueryImpl(StatementImpl.java:196),	at com.clickhouse.jdbc.PreparedStatementImpl.executeQuery(PreparedStatementImpl.java:138),	at com.clickhouse.jdbc.metadata.DatabaseMetaDataImpl.getTables(DatabaseMetaDataImpl.java:998),	at com.mchange.v2.c3p0.impl.NewProxyDatabaseMetaData.getTables(NewProxyDatabaseMetaData.java:4174),	at metabase.driver.clickhouse_introspection$get_tables_from_metadata.invokeStatic(clickhouse_introspection.clj:109),	at metabase.driver.clickhouse_introspection$get_tables_from_metadata.invoke(clickhouse_introspection.clj:107),	at metabase.driver.clickhouse_introspection$get_all_tables_in_all_dbs$fn__173063.invoke(clickhouse_introspection.clj:128),	at metabase.driver.clickhouse$fn__173529$fn__173531.invoke(clickhouse.clj:102),	at metabase.driver.sql_jdbc.execute$do_with_resolved_connection.invokeStatic(execute.clj:366),	at metabase.driver.sql_jdbc.execute$do_with_resolved_connection.invoke(execute.clj:338),	at metabase.driver.clickhouse$fn__173529.invokeStatic(clickhouse.clj:79),	at metabase.driver.clickhouse$fn__173529.invoke(clickhouse.clj:77),	at clojure.lang.MultiFn.invoke(MultiFn.java:244),	at metabase.driver.clickhouse_introspection$get_all_tables_in_all_dbs.invokeStatic(clickhouse_introspection.clj:125),	at metabase.driver.clickhouse_introspection$get_all_tables_in_all_dbs.invoke(clickhouse_introspection.clj:119),	at metabase.driver.clickhouse_introspection$fn__173076.invokeStatic(clickhouse_introspection.clj:170),	at metabase.driver.clickhouse_introspection$fn__173076.invoke(clickhouse_introspection.clj:166)
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