[MXS-4077] Show all databases with schemarouter in GUI Created: 2022-04-05 Updated: 2023-10-04 Resolved: 2023-10-04 |
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| Status: | Closed |
| Project: | MariaDB MaxScale |
| Component/s: | maxgui, schemarouter |
| Affects Version/s: | 6 |
| Fix Version/s: | N/A |
| Type: | New Feature | Priority: | Major |
| Reporter: | Richard Stracke | Assignee: | markus makela |
| Resolution: | Incomplete | Votes: | 1 |
| Labels: | None | ||
| Issue Links: |
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| Description |
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The GUI uses multiple queries to information_schema to build up the list of databases. As these queries are not handled by the schemarouter like SHOW DATABASES is, the GUI will only show the databases of the node that the query ended up on. To solve this problem, the schemarouter would have to query the contents of the required information_schema tables, store it, parse the SQL the client requests and then generate a result that matches that query. In practice, this means either full cross-shard query support or at least partial support for a very limited set of SQL queries. Maxscale GUI not show all databases in the query editor. Maxscale GUI use information_schema.schemata. Schemarouter use "show databases", |
| Comments |
| Comment by Naresh Chandra [ 2022-04-08 ] |
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Can we use only show databases command would be good as its common for even other third party tools as well. |
| Comment by Duong Thien Ly [ 2022-04-25 ] |
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After consideration, the behavior of the schemarouter can be thought of as intended behavior as it was never designed to combine data from multiple different sources. Making changes to the schemarouter to support the query to the "information_schema" would cause complexity. On the other hand, replacing all the queries to "information_schema" in the GUI would break some GUI functionalities such as schemas' object tooltips and the ALTER TABLE feature. |
| Comment by Naresh Chandra [ 2022-04-25 ] |
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Hi Duong, If we use schema router in the Maxscale GUI, then it will not show databases then that will be an issue right? |
| Comment by markus makela [ 2022-04-25 ] |
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The GUI isn't designed to work with the schemarouter and it cannot be modified to support a sharded topology that uses the schemarouter. The schemarouter also does not do cross-shard joins on tables that exist on multiple servers (a documented limitation) which means the SQL is only executed on one server. Implementing cross-shard joins is not something that is supported and won't be easy to implement. If you wish, you can file a new feature request for adding cross-shard join support to schemarouter or we can re-open this one and convert it into a feature request. For now, this is expected behavior and is not something we can consider a bug. |
| Comment by Naresh Chandra [ 2022-04-30 ] |
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Can you please reopen this ticket to feature request? |
| Comment by markus makela [ 2022-04-30 ] |
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Reopening as a feature request. |