Re: "Multiple table synchronizations are processed serially" still happens

On Fri, May 21, 2021 at 1:30 AM Guillaume Lelarge
<guillaume@lelarge.info> wrote:
>
>
>> If so, the
>> problem might be that copying the data of the first table creates a
>> transaction which blocks creation of the slot for second table copy.
>
>
> I don't understand how a transaction could block the creation of a slot. Could you explain that to me?
>

During the creation of the slot, we need to build the initial snapshot
which is used for decoding WAL. Now, to build the initial snapshot, we
wait for all running xacts to finish. See functions
CreateReplicationSlot() and SnapBuildFindSnapshot().

-- 
With Regards,
Amit Kapila.