Hi po 7. 7. 2025 v 5:12 odesÃlatel Paul Jungwirth <p...@illuminatedcomputing.com> napsal:
> Hi Hackers, > > Here are some documentation patches about inlining SQL-language functions. > Postgres has been able to > inline both scalar and set-returning functions since the 9.x days (as long > as they are LANGUAGE SQL > and meet a bunch of other conditions). But this was never documented > outside of a wiki page[1]. This > is a very significant optimization, especially for SRFs with qual > pushdown, but it is largely > unknown. I recently checked five books on advanced Postgres usage, some > specifically on query > optimization, and none of them mentioned this feature. I think we should > talk about it. > > Putting this in our docs also gives us a useful reference point for some > support requests that do > similar inlining, but with more user control. We already have a support > request to let users inline > single-result SQL functions[2], and I have a patch to do something similar > for set-returning SQL > functions[3]. I gave a talk at Postgres Extensions Day in Montreal that > ties all this together,[4] > and our docs could do something similar. > > The first patch just adds <sect2> elements to break up the Function > Optimization section into two > sub-sections: one covering declarative annotations and another covering > support functions. No > rewriting is needed. > > The second patch adds a new <sect2> explaining how we inline SQL > functions: both single-result and > set-returning. Since this happens automatically, it makes a nice > progression with the (easy) > declarative annotations and the (hard) support functions. > > I wonder if we should have some tests about this behavior also? I'm happy > to add those, either as > part of this commitfest entry or something separate. > > [1] https://wiki.postgresql.org/wiki/Inlining_of_SQL_functions > [2] > > https://github.com/postgres/postgres/blob/bd3f59fdb71721921bb0aca7e16d483f72e95779/src/include/nodes/supportnodes.h#L64 > [3] https://commitfest.postgresql.org/patch/5083/ > [4] https://github.com/pjungwir/inlining-postgres-functions > > I am checking this patch. The new content is very necessary. I think the related page is well readable after patching. This patch can be enhanced by some examples, and with a description how to detect if a function was inlined or not. Reards Pavel > Yours, > > -- > Paul ~{:-) > p...@illuminatedcomputing.com >
