Ok thanks for all these precisions Regards Fabrice On Tue, Dec 19, 2023 at 2:00 PM Matthias van de Meent < boekewurm+postg...@gmail.com> wrote:
> On Tue, 19 Dec 2023, 12:27 Fabrice Chapuis, <fabrice636...@gmail.com> > wrote: > > > > Hi, > > Is it possible to visualize the DDL with the pg_waldump tool. I created > a postgres user but I cannot find the creation command in the wals > > Not really, no. PostgreSQL does not log DDL or DML as such in WAL. > Essentially all catalog updates are logged only as changes on a > certain page in some file: a new user getting inserted would be > approximately "Insert tuple [user's pg_role row data] on page X in > file [the file corresponding to the pg_role table]". > > You could likely derive most DDL commands from Heap/Insert, > Heap/Delete, and Heap/Update records (after cross-referencing the > database's relfilemap), as most DDL is "just" a lot of in-memory > operations plus some record insertions/updates/deletes in catalog > tables. You'd also need to keep track of any relfilemap changes while > processing the WAL, as VACUUM FULL on the catalog tables would change > the file numbering of catalog tables... > > Kind regards, > > Matthias van de Meent > Neon (https://neon.tech) >
