> On Mon, May 06, 2024 at 06:52:41PM +0530, Ashutosh Bapat wrote: > On Sun, May 5, 2024 at 1:43 AM Dmitry Dolgov <9erthali...@gmail.com> wrote: > > I had a quick look, it covers the issues mentioned above in the thread. > > Few nitpicks/questions: > > > > * I think it makes sense to verify if the ptup is valid. This approach > > would fail if the target column of the root partition is marked as > > attisdropped. > > > > The column is searched by name which is derived from attno of child > partition. So it has to exist in the root partition. If it doesn't > something is seriously wrong. Do you have a reproducer? We may want to add > Assert(HeapTupleIsValid(ptup)) just in case. But it seems unnecessary to me.
Sure, normally it should work. I don't have any particular situation in mind, when attisdropped might be set on a root partition, but obviously setting it manually crashes this path. Consider it mostly as suggestion for a more defensive implementation "just in case". > > Oid > > -getIdentitySequence(Oid relid, AttrNumber attnum, bool missing_ok) > > +getIdentitySequence(Relation rel, AttrNumber attnum, bool missing_ok) > > { > > > > [...] > > > > + relid = llast_oid(ancestors); > > + ptup = SearchSysCacheAttName(relid, attname); > > + attnum = ((Form_pg_attribute) GETSTRUCT(ptup))->attnum; > > > > * getIdentitySequence is used in build_column_default, which in turn > > often appears in loops over table attributes. AFAICT it means that the > > same root partition search will be repeated multiple times in such > > situations if there is more than one identity. I assume the > > performance impact of this repetition is negligible? > > > > I thought having multiple identity columns would be rare and hence avoided > making code complex. Otherwise we have to get root partition somewhere in > the caller hierarchy separately the logic much farther apart. Usually the > ancestor entries will be somewhere in the cache Yeah, agree, it's reasonable to expect that the case with multiple identity columns will be rare.