Обсуждение: Re: pgsql: Ignore PlaceHolderVars when looking up statistics
On Sun, Dec 28, 2025 at 9:45 PM Richard Guo <rguo@postgresql.org> wrote: > Ignore PlaceHolderVars when looking up statistics > > Back-patch to v18. Although this issue exists before that, changes in > this version made it common enough to notice. Given the lack of field > reports for older versions, I am not back-patching further. Generally we don't back-patch fixes that could change plans, because it tends to produce user complaints. It's maybe more justifiable in this case because v18 is quite new and you didn't back-patch to older releases, but are we sure that it's warranted even there? -- Robert Haas EDB: http://www.enterprisedb.com
Robert Haas <robertmhaas@gmail.com> writes: > On Sun, Dec 28, 2025 at 9:45 PM Richard Guo <rguo@postgresql.org> wrote: >> Back-patch to v18. Although this issue exists before that, changes in >> this version made it common enough to notice. Given the lack of field >> reports for older versions, I am not back-patching further. > Generally we don't back-patch fixes that could change plans, because > it tends to produce user complaints. It's maybe more justifiable in > this case because v18 is quite new and you didn't back-patch to older > releases, but are we sure that it's warranted even there? It's a regression if we don't. See nearby complaint at https://www.postgresql.org/message-id/flat/b75866aa-bb54-456b-8f88-6b5bc52064ca%40app.fastmail.com That case was correctly handled in v17 and before. regards, tom lane
On Fri, Jan 2, 2026 at 4:20 PM Tom Lane <tgl@sss.pgh.pa.us> wrote: > It's a regression if we don't. See nearby complaint at > > https://www.postgresql.org/message-id/flat/b75866aa-bb54-456b-8f88-6b5bc52064ca%40app.fastmail.com > > That case was correctly handled in v17 and before. Oh, OK. Probably makes sense then, since v18 is new. -- Robert Haas EDB: http://www.enterprisedb.com
On Sat, Jan 3, 2026 at 6:20 AM Tom Lane <tgl@sss.pgh.pa.us> wrote: > Robert Haas <robertmhaas@gmail.com> writes: > > Generally we don't back-patch fixes that could change plans, because > > it tends to produce user complaints. It's maybe more justifiable in > > this case because v18 is quite new and you didn't back-patch to older > > releases, but are we sure that it's warranted even there? > It's a regression if we don't. That's right. I was actually of two minds for a while regarding the back-patch, but in the end decided to proceed. You can find the discussions and the reasoning behind this decision in the link below. https://postgr.es/m/CAMbWs49h5F66KZwLxaeXoLwHe_9jAB7Eu44UmJhhQpLA38tKhw@mail.gmail.com - Richard