Bruce Momjian wrote: > > Hiroshi Inoue wrote: > > Tom Lane wrote: > > > > > Hiroshi's "DROP_COLUMN_HACK" was essentially along this line, but > > > I think he made a representational mistake by trying to change the > > > attnums of dropped columns to be negative values. > > > > Negative attnums had 2 advantages then. It had a big > > advantage that initdb isn't needed. Note that it was > > only a trial hack and there was no consensus on the way. > > It was very easy to change the implementation to use > > attisdropped. OTOH physical/logical attnums approach > > needed the change on pg_class, pg_attribute and so > > I've never had a chance to open the patch to public. > > It was also more sensitive about oversights of needed > > changes than the attisdropped flag approach. > > > > > That means that > > > a lot of low-level places *do* need to know about the dropped-column > > > convention, else they can't make any sense of tuple layouts. > > > > Why ? As you already mentioned, there were not that many places > > to be changed. > > > > Well what's changed since then ? > > Here is an old email from me that outlines the idea of having a > physical/logical attribute numbering system, and the advantages.
I already tried physical/logical attribute implementation pretty long ago. Where are new ideas to solve the problems that the approach has ? regards, Hiroshi Inoue ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
