Re: Logical replication on two identical databases but diff versions

Thank you, Tim.
I was always trying ways to speed up initial sync, did not know i could try
this route.
(*sorry for top post, but hopefully this is the end of thread)

On Sat, Jun 18, 2022, 4:50 AM Tim <timfosho(at)gmail(dot)com> wrote:

> >> Is this expected ?
>
> Yes, this is expected.
>
> >> If this is expected, that means i can have a
> >> no downtime upgrade ?
>
> Indeed you can.
>
> >> Is this correct?
>
> This is correct.
>
> On Fri, Jun 17, 2022 at 2:35 PM Vijaykumar Jain <
> vijaykumarjain(dot)github(at)gmail(dot)com> wrote:
>
>> Hi,
>>
>> i have two db servers pg12 and pg14 and they have exactly the same data
>> in all schemas and tables. I tried linking both by setting
>> wal_level=logical and make pg12 publisher and pg14 subscriber (with
>> copy_data = false, create_slot = false, enabled = false)
>> Then i created a logical replication slot on pg12 and enabled
>> subscription and logical replication was running just fine and all changes
>> from pg12 going to pg14...
>> Is this expected ? I did not play with any of advancing of lsn anywhere...
>>
>> If this is expected, that means i can have a pg12 cluster of primary and
>> replica ... then i can take the replica out of cluster , make it writable
>> using pg_promote and then pg_upgrade it to pg14 and then link it like above
>> to old pg12 via logical replication...and then slowly after ensuring no
>> issues, phase out pg12 and replace it with pg14, no downtime upgrade ?
>>
>> Is this correct? (Of course no schema changes while this is being done)
>> and i set max_wal_size to a large value to retain enough wals.
>>
>>
>>