On Mon, Apr 06, 2026 at 05:11:30PM -0400, Andres Freund wrote:
> heap_insert()
> ->CacheInvalidateHeapTuple()
> ->CacheInvalidateHeapTupleCommon()
> ->AssertCouldGetRelation()
> not being cheap and running a *lot*.
>
> Admittedly it's way worse if you build with -O0, which I tend to do to make
> debugging easier.
>
> In that config, the assert single-handled increases the time for a repack by
> 35% or so.
>
>
> Noah, is there any reason we need to do the AssertCouldGetRelation() before
> the !IsCatalogRelation(relation)? Given that the goal is to make
> RelationGetRelid() safe, it doesn't seem there is?
By running AssertCouldGetRelation() during every INSERT statement, this
detects cases that would be unsafe when the target of the INSERT happens to be
a system catalog. Little of our INSERT/UPDATE coverage targets a system
catalog. Hence, the current position is better for detection.
I wonder if this got slower in v19. In v14-v18, the assert's cost is
proportional to the number of held lwlocks, often 0 or 1. In v19, it's
proportional to PrivateRefCountHash cardinality.
