"Peter J. Holzer" <hjp-pgsql@xxxxxx> writes: > On 2022-10-01 20:24:21 +0800, Julien Rouhaud wrote: >> This is intentional, and documented at >> https://www.postgresql.org/docs/14/runtime-config-custom.html. > So it's there but hard to find (I did read the table of contents at > https://www.postgresql.org/docs/14/runtime-config.html but I guess after > all the subchapters about specific configuration parameters I didn't > notice the one generic subchapter near the end). > I think referring to that chapter from > https://www.postgresql.org/docs/14/sql-set.html and possibly other > places would help. Up to now, there's been an intentional policy of not documenting this very prominently, because doing so would encourage people to abuse such variables as application state variables. I say "abuse" because the code supporting such variables isn't really designed to support lots of them. There has been a patch in the works for a long time to provide a better mechanism for application state variables [1]. Separately, I did some work recently towards alleviating the performance problems with lots of custom parameters [2]. It appears from the discussion in [2] that we're probably going to stick to the policy of not encouraging use of custom parameters as application state, although if [1] keeps failing to land maybe that will change? regards, tom lane [1] https://www.postgresql.org/message-id/flat/CAFj8pRD053CY_N4=6SvPe7ke6xPbh=K50LUAOwjC3jm8Me9Obg@xxxxxxxxxxxxxx [2] https://www.postgresql.org/message-id/flat/2982579.1662416866@xxxxxxxxxxxxx
