On Fri, Dec 3, 2021 at 9:02 PM Tom Lane <tgl@xxxxxxxxxxxxx> wrote: > > Dilip Kumar <dilipbalaut@xxxxxxxxx> writes: > > On Thu, Dec 2, 2021 at 9:35 AM Dilip Kumar <dilipbalaut@xxxxxxxxx> wrote: > >> I think there is no such view or anything which tells about which > >> backend or transaction has more than 64 sub transaction. But if we > >> are ready to modify the code then we can LOG that information in > >> GetNewTransactionId(), when first time we are marking it overflown. > > > I have prepared a small patch to log this information. > > Putting an elog call into GetNewTransactionId seems like a completely > horrid idea from a performance standpoint. Especially if you put it > inside the XidGenLock hold, where it can block the entire system not just > the one process. But even without that, this seems like a performance > penalty with basically no real-world benefit. People who have issues > like this are not going to want to trawl the postmaster log for such > messages. Agreed with both points. What about we add, subxid count and overflow status in LocalPgBackendStatus and through that, we can show in pg_stat_activity. That way we don't have to report it ever and whenever the user is running pg_stat_activity they can fetch it directly from "proc->subxidStatus", along with fetching the proc.xid and proc.xmin. Does this make sense? -- Regards, Dilip Kumar EnterpriseDB: http://www.enterprisedb.com
