Add support for IBM Power System i

[Mcalti93]

General

We're encountering issues using Reactive Hibernate with Vert.x reactive db2 client and DB2 hosted on IBM Power i (AS400) v7.4. It appears that the Vert.x Reactive DB2 Client explicitly supports only DB2 on Linux, Unix, and Windows and and possibly DB2 for z/OS as mentioned here.

Problem Description:

When attempting to connect, the server's release version string on IBM Power i begins with "V" (e.g., V07R04M00). The Vert.x reactive db2 client expects the release version to start with either SQL (for Linux/Unix/Windows) or DSN (for DB2 z/OS). This mismatch triggers the following exception:
java.lang.IllegalArgumentException: Received unknown server product release level: V07R04M00

As a result, the DB connection initialization immediately fails.

Environment:

Reactive Hibernate

Vert.x

IBM Power i v7.4

Feature

Is the lack of support for DB2 on IBM Power i due to known compatibility issues or simply because it is a proprietary system and hasn't been tested/supported yet?

Clarification on this point would help us understand if there are inherent limitations or if future support could be expected.

[vietj]

the current implementation for DB2 seems good, however there is a lack of contributor with DB2 specific knowledge.

we would welcome any contributor helping there

[vietj]

things are documented but the protocol seems to be quite complicated to get (unlike PostgreSQL for instance)

[Mcalti93]

Okay, thank you for your answer. Using DB2 on Power i together with vert.x is probably quite a niche, yes. Do you think it's worth a try for us to get around the thrown exception? Or is the protocol that different from z/OS and DB2 on Windows/Linux?

[vietj]

Protocol should be the same regardless of the OS.

I don't exactly know what means limited for zOS in this context, we should ask the original contributor what he meant about this I think. @aguibert any idea

[mswatosh]

Do you think it's worth a try for us to get around the thrown exception? Or is the protocol that different from z/OS and DB2 on Windows/Linux?

If I remember correctly the OS check that's being hit here is because initial handshake between Db2/z and Db2 LUW are different. I don't remember how much it varies after that point, but my guess is even if you tried to go down the LUW or z path for Db2 for i you would hit issues.