On Wed, Jul 2, 2025 at 4:32 PM Andrei Lepikhov <lepi...@gmail.com> wrote: > I must say that I appreciate Tom's idea and see significant benefits in > making the parse tree a read-only structure. In complex queries, it can > be frustrating to make copies of the parse tree, leading to complaints > from users about insufficient memory allocation. This is why, in our > enterprise fork, we support a specific option to avoid copying the parse > tree multiple times.
I don't see how the changes in this patchset violate Tom's proposal regarding keeping the parse tree read-only. The only potential issue I can see is that we may clear the rte->inh flag in some cases -- but that behavior has existed for a long time, not starting from this patchset. > Therefore, it would be better to find a way to refactor the > `preprocess_relation_rtes` function to gather table statistics lazily > into the hash table when they are needed. For example, we could do this > at the moment of creating the `RelOptInfo` or before a subquery pull-up, > without modifying the RTE at all. All the catalog information collected in preprocess_relation_rtes() is needed very early in the planner. I don't see how we could move that logic to a later stage, such as at the moment of creating RelOptInfos as you mentioned. Thanks Richard
