st 7. 8. 2024 v 12:22 odesílatel Alexander Korotkov <aekorot...@gmail.com> napsal:
> On Wed, Aug 7, 2024 at 1:03 PM Pavel Stehule <pavel.steh...@gmail.com> > wrote: > > > > st 7. 8. 2024 v 10:52 odesílatel Alexander Korotkov < > aekorot...@gmail.com> napsal: > >> > >> Hi, Pavel! > >> > >> On Wed, Aug 7, 2024 at 9:35 AM Pavel Stehule <pavel.steh...@gmail.com> > wrote: > >> > st 7. 8. 2024 v 6:08 odesílatel Alexander Korotkov < > akorot...@postgresql.org> napsal: > >> >> > >> >> Introduce hash_search_with_hash_value() function > >> >> > >> >> This new function iterates hash entries with given hash values. > This function > >> >> is designed to avoid full sequential hash search in the syscache > invalidation > >> >> callbacks. > >> >> > >> >> Discussion: > https://postgr.es/m/5812a6e5-68ae-4d84-9d85-b443176966a1%40sigaev.ru > >> >> Author: Teodor Sigaev > >> >> Reviewed-by: Aleksander Alekseev, Tom Lane, Michael Paquier, Roman > Zharkov > >> >> Reviewed-by: Andrei Lepikhov > >> > > >> > > >> > I tried to use hash_seq_init_with_hash_value in session variables > patch, but it doesn't work there. > >> > > >> > <-->if (!sessionvars) > >> > <--><-->return; > >> > > >> > elog(NOTICE, "%u", hashvalue); > >> > > >> > > >> > <-->hash_seq_init(&status, sessionvars); > >> > > >> > <-->while ((svar = (SVariable) hash_seq_search(&status)) != NULL) > >> > <-->{ > >> > <--><-->if (hashvalue == 0 || svar->hashvalue == hashvalue) > >> > <--><-->{ > >> > <--><--><-->elog(NOTICE, "FOUND OLD"); > >> > <--><--><-->svar->is_valid = false; > >> > <--><-->} > >> > <-->} > >> > > >> > > >> > > >> > <-->/* > >> > <--> * If the hashvalue is not specified, we have to recheck all > currently > >> > <--> * used session variables. Since we can't tell the exact session > variable > >> > <--> * from its hashvalue, we have to iterate over all items in the > hash bucket. > >> > <--> */ > >> > <-->if (hashvalue == 0) > >> > <--><-->hash_seq_init(&status, sessionvars); > >> > <-->else > >> > <--><-->hash_seq_init_with_hash_value(&status, sessionvars, > hashvalue); > >> > > >> > <-->while ((svar = (SVariable) hash_seq_search(&status)) != NULL) > >> > <-->{ > >> > <--><-->Assert(hashvalue == 0 || svar->hashvalue == hashvalue); > >> > > >> > elog(NOTICE, "found"); > >> > > >> > <--><-->svar->is_valid = false; > >> > <--><-->needs_validation = true; > >> > <-->} > >> > } > >> > > >> > Old methods found an entry, but new not. > >> > > >> > What am I doing wrong? > >> > >> I'm trying to check this. Applying this patch [1], but got conflicts. > >> Could you please, rebase the patch, so I can recheck the issue? > > > > I sent rebased patchset > > > Thank you. > Please see 40064a8ee1 takes special efforts to match HTAB hash > function to syscache hash function. By default, their hash values > don't match and you can't simply use syscache hash value to search > HTAB. This probably should be mentioned in the header comment of > hash_seq_init_with_hash_value(). > yes, enhancing doc should be great + maybe assert Regards Pavel > > ------ > Regards, > Alexander Korotkov > Supabase >
