On Fri, May 14, 2021 at 3:12 AM Bruce Momjian <br...@momjian.us> wrote: > > > Maybe we should revert this thing pending somebody doing the work to > > make a version of queryid labeling that actually is negligibly cheap. > > It certainly seems like that could be done; one more traversal of the > > parse tree can't be that expensive in itself. I suspect that the > > performance problem is with the particular hashing mechanism that > > was used, which looks mighty ad-hoc anyway. > > I was surprised it was ~2%.
Just to be clear, the 2% was a worst case scenario, ie. a very fast read-only query on small data returning a single row. As soon as you get something more realistic / expensive the overhead goes away. For reference here is the detail: https://www.postgresql.org/message-id/CAOBaU_ZVmGPfKTwZ6cM_qdzaF2E1gMkrLDMwwLy4Z1JxQ6=c...@mail.gmail.com
