Hi everyone,
thanks for this healthy discussion. Looking at high number of
participants, it looks like we definitely want this feature. We just
need to figure out the "how".
This reminds me very much of the discussion we had for CREATE FUNCTION.
There, we discussed whether functions should be named globally or
catalog-specific. In the end, we decided for both `CREATE SYSTEM
FUNCTION` and `CREATE FUNCTION`, satisfying both the data platform team
of an organization (which might provide system functions) and individual
data teams or use cases (scoped by catalog/database).
Looking at other modern vendors like Snowflake there is SECRET (scoped
to schema) [1] and API INTEGRATION [2] (scoped to account). So also
other vendors offer global and per-team / per-use case connections details.
In general, I think fitting connections into the existing concepts for
catalog objects (with three-part identifier) makes managing them easier.
But I also see the need for global defaults.
Btw keep in mind that a catalog implementation should only store
metadata. Similar how a CatalogTable doesn't store the actual data, a
CatalogConnection should not store the credentials. It should only offer
a factory that allows for storing and retrieving them. In real world
scenarios a factory is most likely backed by a product like Azure Key Vault.
So code-wise having a ConnectionManager that behaves similar to
FunctionManager sounds reasonable.
+1 for having special syntax instead of using properties. This allows to
access connections in tables, models, functions. And catalogs, if we
agree to have global ones as well.
What do you think?
Let me spend some more thoughts on this and come back with a concrete
proposal by early next week.
Cheers,
Timo
[1] https://docs.snowflake.com/en/sql-reference/sql/create-secret
[2] https://docs.snowflake.com/en/sql-reference/sql/create-api-integration
On 04.06.25 10:47, Leonard Xu wrote:
Hey，Mayank
Please see my feedback as following:
1. One of the motivations of this FLIP is to improve security. However, the
current design stores all connection information in the catalog,
and each Flink SQL job reads from the catalog during compilation. The
connection information is passed between SQL Gateway and the
catalog in plaintext, which actually introduces new security risks.
2. The name "Connection" should be changed to something like ConnectionSpec to
clearly indicate that it is a object containing only static
properties without a lifecycle. Putting aside the naming issue, I think the
current model and hierarchy design is somewhat strange. Storing
various kinds of connections (e.g., Kafka, MySQL) in the same Catalog with
hierarchical identifiers like catalog-name.db-name.connection-name
raises the following questions:
(1) What is the purpose of this hierarchical structure of Connection object ?
(2) If we can use a Connection to create a MySQL table, why can't we use a
Connection to create a MySQL Catalog?
3. Regarding the connector usage examples given in this FLIP:
```sql
1 -- Example 2: Using connection for jdbc tables
2 CREATE OR REPLACE CONNECTION mysql_customer_db
3 WITH (
4 'type' = 'jdbc',
5 'jdbc.url' = 'jdbc:mysql://customer-db.example.com:3306/customerdb',
6 'jdbc.connection.ssl.enabled' = 'true'
7 );
8
9 CREATE TABLE customers (
10 customer_id INT,
11 PRIMARY KEY (customer_id) NOT ENFORCED
12 ) WITH (
13 'connector' = 'jdbc',
14 'jdbc.connection' = 'mysql_customer_db',
15 'jdbc.connection.ssl.enabled' = 'true',
16 'jdbc.connection.max-retry-timeout' = '60s',
17 'jdbc.table-name' = 'customers',
18 'jdbc.lookup.cache' = 'PARTIAL'
19 );
```
I see three issues from SQL semantics and Connector compatibility perspectives:
(1) Look at line 14: `mysql_customer_db` is an object identifier of a
CONNECTION defined in SQL. However, this identifier is referenced
via a string value inside the table’s WITH clause, which feel hack for me.
(2) Look at lines 14–16: the use of the specific prefix `jdbc.connection` will
confuse users because `connection.xx` maybe already used as
a prefix for existing configuration items.
(3) Look at lines 14–18: Why do all existing configuration options need to be
prefixed with `jdbc`, even they’re not related to Connection properties?
This completely changes user habits — is it backward compatible?
In my opinion, Connection should be a model independent of both Catalog and Table, and can be referenced by all catalog/table/udf/model object.
It should be managed by a Component such as a ConnectionManager to enable
reuse. For security purposes, authentication mechanisms could
be supported within the ConnectionManager.
Best,
Leonard
2025 6月 4 02:04，Martijn Visser <martijnvis...@apache.org> 写道：
Hi all,
First of all, I think having a Connection resource is something that will
be beneficial for Apache Flink. I could see that being extended in the
future to allow for easier secret handling [1].
In my mental mind, I'm comparing this proposal against SQL/MED from the ISO
standard [2]. I do think that SQL/MED isn't a very user friendly syntax
though, looking at Postgres for example [3].
I think it's a valid question if Connection should be considered with a
catalog or database-level scope. @Ryan can you share something more, since
you've mentioned "Note: I much prefer catalogs for this case. Which is what
we use internally to manage connection properties". It looks like there
isn't a strong favourable approach looking at other vendors (like,
Databricks does scopes it on a Unity catalog, Snowflake on a database
level).
Also looking forward to Leonard's input.
Best regards,
Martijn
[1] https://issues.apache.org/jira/browse/FLINK-36818
[2] https://www.iso.org/standard/84804.html
[3] https://www.postgresql.org/docs/current/sql-createserver.html
On Fri, May 30, 2025 at 5:07 AM Leonard Xu <xbjt...@gmail.com> wrote:
Hey Mayank.
Thanks for the FLIP, I went through this FLIP quickly and found some
issues which I think we
need to deep discuss later. As we’re on a short Dragon boat Festival,
could you kindly hold
on this thread? and we will back to continue the FLIP discuss.
Best,
Leonard
2025 4月 29 23:07，Mayank Juneja <mayankjunej...@gmail.com> 写道：
Hi all,
I would like to open up for discussion a new FLIP-529 [1].
Motivation:
Currently, Flink SQL handles external connectivity by defining endpoints
and credentials in table configuration. This approach prevents
reusability
of these connections and makes table definition less secure by exposing
sensitive information.
We propose the introduction of a new "connection" resource in Flink. This
will be a pluggable resource configured with a remote endpoint and
associated access key. Once defined, connections can be reused across
table
definitions, and eventually for model definition (as discussed in
FLIP-437)
for inference, enabling seamless and secure integration with external
systems.
The connection resource will provide a new, optional way to manage
external
connectivity in Flink. Existing methods for table definitions will remain
unchanged.
[1] https://cwiki.apache.org/confluence/x/cYroF
Best Regards,
Mayank Juneja
