On Wed, Jul 3, 2024 at 5:34 AM Fujii Masao <masao.fu...@oss.nttdata.com> wrote: > pg_wal_summary_contents() seems to miss the summary information with "limit" > that pg_walsummary reports. This appears to be a bug. The attached patch > fixes this.
Oops. It looks like pg_wal_summary_contents() forgets to emit the limit block when that's the only data for a particular relation fork. And maybe you can make it emit the limit block multiple times if the list of block numbers is long enough. Thanks for the patch. I think you can commit and back-patch this, but I don't think the commit message is quite right, because it's not like this code just NEVER executes where it is located currently. Or am I missing something? > By the way, pg_wal_summary_contents() and pg_walsummary perform nearly the > same task but are implemented in different functions. This could be the root > of issues like this. In the future, it would be better to have a common > function for outputting the WAL summary file that both can use. It's entirely possible that, with some refactoring, more code could be shared. I tried to make all of the blkreftable stuff reusable, but I didn't pay as much attention to synchronizing up the various users of it. However, the fact that pg_walsummary is frontend code and pg_wal_summary_contents() is backend code does make it hard to get perfect reuse. I think if you go through pg_wal_summary_contents(), you'll find that almost every line of that function contains something backend-specific. -- Robert Haas EDB: http://www.enterprisedb.com
