On Mon, May 4, 2026 at 8:09 PM Euler Taveira <euler@eulerto.com> wrote:
On Mon, May 4, 2026, at 10:11 PM, SATYANARAYANA NARLAPURAM wrote: > > Virtual generated columns are not stored on disk, so heap_getattr() in > tuple_to_stringinfo() always returned NULL for them, producing > misleading output such as > > table public.t: INSERT: a[integer]:1 b[integer]:10 c[integer]:null > > even though the user could observe a non-null value via SELECT. Stored > generated columns continue to be emitted as before because their values > do live in the heap tuple. >
I wouldn't say misleading but expected. Logical decoding relies on WAL and virtual generated columns are not stored in the WAL.
> This matches the pgoutput's logicalrep_should_publish_column() > which never publishes virtual generated columns. Added a regression test. > Please find the patch attached. >
There is no guarantee that test_decoding should match the pgoutput.
Agreed, not trying to keep them in sync but giving as a reference.
I agree that test_decoding shouldn't output virtual generated columns. The problem is that it already does it. I'm afraid that removing it should break existing applications. (I heard that some solutions rely on test_decoding for CDC.) Should we change it as you proposed or add an option to put it back to keep the old behavior?
It is emitting null, I am not sure if it is meaningful for the consumers to consume this or
have taken dependency on this. Adding an extra option isn't an overkill for this? I am open
to this idea if others feel the same.
I didn't review your patch but I noticed that there is a new test file for this change. There are some concerns about the total test execution time. Do you really need to include this test? If so, should you combine it with an existing test file?
Fair concern, I moved the tests to ddl.sql. Please find the attached v2 patch.
