Hi, On Sat, Mar 16, 2024 at 06:46:15PM -0400, Tom Lane wrote: > Laurenz Albe <laurenz.a...@cybertec.at> writes: > > On Fri, 2024-03-15 at 19:18 -0400, Tom Lane wrote: > >> This patch seems to have stalled out again. In hopes of getting it > >> over the finish line, I've done a bit more work to address the two > >> loose ends I felt were probably essential to deal with: > > > Applies and builds fine. > > I didn't scrutinize the code, but I gave it a spin on a database with > > 15 million (small) large objects. I tried pg_upgrade --link with and > > without the patch on a debug build with the default configuration. > > Thanks for looking at it! > > > Without the patch: > > Runtime: 74.5 minutes > > > With the patch: > > Runtime: 70 minutes > > Hm, I'd have hoped for a bit more runtime improvement.
I also think that this is quite a large runtime for pg_upgrade, but the more important savings should be the memory usage. > But perhaps not --- most of the win we saw upthread was from > parallelism, and I don't think you'd get any parallelism in a > pg_upgrade with all the data in one database. (Perhaps there is more > to do there later, but I'm still not clear on how this should interact > with the existing cross-DB parallelism; so I'm content to leave that > question for another patch.) What is the status of this? In the commitfest, this patch is marked as "Needs Review" with Nathan as reviewer - Nathan, were you going to take another look at this or was your mail from January 12th a full review? My feeling is that this patch is "Ready for Committer" and it is Tom's call to commit it during the next days or not. I am +1 that this is an important feature/bug fix to have. Because we have customers stuck on older versions due to their pathological large objects usage, I did some benchmarks (jsut doing pg_dump, not pg_upgarde) a while ago which were also very promising; however, I lost the exact numbers/results. I am happy to do further tests if that is required for this patch to go forward. Also, is there a chance this is going to be back-patched? I guess it would be enough if the ugprade target is v17 so it is less of a concern, but it would be nice if people with millions of large objects are not stuck until they are ready to ugprade to v17. Michael
