Re: Server Crashes if try to provide slot_name='none' at the time of creating subscription.

On Mon, May 15, 2017 at 8:22 PM, Kuntal Ghosh
<kuntalghosh(dot)2007(at)gmail(dot)com> wrote:
> On Mon, May 15, 2017 at 4:39 PM, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
>
> While testing with logical replication, I've found that the server
> hangs if we create a subscription to the same server. For example,
>
> $ ./pg_ctl -D Test start -o "-p 5432"
> $ ./psql -p 5432 postgres -c "CREATE PUBLICATION abc for all tables
> with (publish='delete');"
> $ ./psql -p 5432 postgres -c "create subscription sub connection
> 'dbname=postgres port=5432 user=edb password=edb' publication abc with
> (slot_name='abcslot');"
> NOTICE: synchronized table states
> LOG: logical decoding found initial starting point at 0/162DF18
> DETAIL: Waiting for transactions (approximately 1) older than 560 to end.
>
> And, it hangs. Is this an expected behavior?

I guess this is what we're discussing on [1].
Petr answered on that,
===
Yes that's result of how logical replication slots work, the transaction
that needs to finish is your transaction. It can be worked around by
creating the slot manually via the SQL interface for example and create
the subscription using WITH (NOCREATE SLOT, SLOT NAME = 'your slot') .
===

[1] https://www.postgresql.org/message-id/20170426165954.GK14000%40momjian.us

Regards,

--
Masahiko Sawada
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center