Re: lastOverflowedXid does not handle transaction ID wraparound

[Andrey Borodin]

> 21 окт. 2021 г., в 09:01, Kyotaro Horiguchi <horikyota....@gmail.com> 
> написал(а):
> 
> If the discussion so far is correct, the following diff will fix the
> issue.
> 
> diff --git a/src/backend/storage/ipc/procarray.c 
> b/src/backend/storage/ipc/procarray.c
> index bd3c7a47fe..19682b73ec 100644
> --- a/src/backend/storage/ipc/procarray.c
> +++ b/src/backend/storage/ipc/procarray.c
> @@ -4463,6 +4463,12 @@ ExpireOldKnownAssignedTransactionIds(TransactionId xid)
> {
>        LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
>        KnownAssignedXidsRemovePreceding(xid);
> +       /*
> +        * reset lastOverflowedXid if we know transactions that have been 
> possiblly
> +        * running are being gone.
> +        */
> +       if (TransactionIdPrecedes(procArray->lastOverflowedXid, xid))
> +               procArray->lastOverflowedXid = InvalidTransactionId;
>        LWLockRelease(ProcArrayLock);
> }

The patch seems correct bugfix to me. The only question I have: is it right 
place from modularity standpoint? procArray->lastOverflowedXid is not a part of 
KnownAssignedTransactionIds?

Best regards, Andrey Borodin.