Hi, On 2026-04-06 18:10:56 -0700, Noah Misch wrote: > 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.
I see. > Little of our INSERT/UPDATE coverage targets a system catalog. Sure. We do have plenty DML doing heap_insert/update however. > Hence, the current position is better for detection. What if we returned early in AssertBufferLocksPermitCatalogRead() if InterruptHoldoffCount == 0? That'd only fail if some code manually did a RESUME_INTERRUPTS() to balance the one acquired as part of the content lock? > 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. Yea, plausible. It will only scan PrivateRefCountHash if PrivateRefCountOverflowed overflowed, but it did overflow in the case I was testing... Greetings, Andres Freund
