On: Db2 is a story worth telling, even if IBM won't

[bantunes]

Does anyone know if the claim that DB2 was at one time the world's largest C++ codebase has any worth?

[skissane → bantunes]

I don’t know about the veracity of that claim. But I presume it is talking about DB2 LUW (Linux/Unix/Windows), which began life as OS/2 Extended Edition Database Manager (although support for OS/2 was dropped a long time ago, that’s the platform on which the code base started.) The original DB2, DB2 for z/OS, is predominantly written in PL/X, an IBM-confidential PL/I dialect, not C++-although it wouldn’t surprise me if nowadays it contained some components written in C and/or C++, from what I’ve heard the bulk of it is still written in PL/X. DB2 for VSE and VM is mostly PL/X and assembler. Parts of DB2 for IBM i may be written in C++ too, but I suspect the bulk of it is IBM-confidential PL/I dialects (not PL/X; PL/MI and PL/MP), with a small chance it may even contain a bit of Modula 2 (I believe some bits of IBM i are still Modula 2 code, probably not anything to do with DB2, but not 100% sure)

[formerly_proven → skissane]

IBM people claim "tens of millions of lines of C/C++ code" in this paper: https://arxiv.org/pdf/2110.08661

Which is certainly a lot.

[skissane → formerly_proven]

Oracle RDBMS contains 10s of millions of lines of code.

But unlike DB2 LUW, it is mostly C, not C++.

[inopinatus → bantunes]

James Hamilton, perhaps; shortly after writing IBM's first C++ compiler he became the architecture lead for DB2 Universal.

[usrnm → bantunes]

Nobody can possibly know that for certain