Re: Fast logical replication jump start with PG 10

Hi Adrian, thanks for your reply. Here is the clarification.

1) It is indeed a pg_upgrade from 9.2 to 10.4. Depending on the test
machine, it runs in between 15 and 20 minutes for just over 100GB. I can
negotiate this time with our customer. The vacuum process took another 5 to
7 minutes. This this what I was referring to with the 30 minutes (point 3
in your questions)

2) After pg_upgrade, I published the tables on the database (in the sense
"CREATE DATABASE") and subscribed to this publication on the second server
(logical replication). The data copy processed started immediately and took
around 1 hour. I then loaded the indexes, what took another 2h20m. At that
point the active-passive cluster was ready to go. Note that the active and
the passive databases are on different machines.

4) By "database" I mean the result of "CREATE DATABASE" and we have 1 per
server (or "cluster" in your terminology - I tend to use this word for a
group of machines). We are currently using a streaming replication between
the 9.2 servers, so it could be a fall-back option after the upgrade (I
wanted to remove part of the indexes on the master to lower the load,
reason to use the logical replication... if the execution time is not too
excessive).

Hope it clarifies the question
Best regards
Olivier

Olivier Gautherot
olivier(at)gautherot(dot)net
Cel:+56 98 730 9361
Skype: ogautherot
www.gautherot.net
http://www.linkedin.com/in/ogautherot

On Fri, May 25, 2018 at 7:51 PM, Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com>
wrote:

> On 05/25/2018 02:12 PM, Olivier Gautherot wrote:
>
>> Hi,
>>
>> I just sent the question on StackOverflow but realized that this audience
>> may be more savvy. So sorry in advance for cross-posting...
>>
>> I'm in the process of upgrading a PG from 9.2 to 10.4. pg_upgrade worked
>> fine on the master and was rather fast. The problem is that the database is
>> replicated and I'm planning to switch from streaming to logical. The
>> problem is that it is rather slow (30 minutes for the master and over 3
>> hours for the replication, between data transfer and indexes).
>>
>
> I am not clear on what you did, so can you clarify the following:
>
> 1) pg_upgrade from 9.2 master instance to 10.4 master instance, correct?
>
> 2) What replication are you talking about for the 3 hour value?
>
> 3) What is the 30 minute value referring to?
>
> 4) When you say database are you talking about a Postgres cluster or a
> database in the cluster?
>
>
>> Is there a way to speed up the replication or should I rather stick to
>> streaming replication? As I have only 1 database on the server, it would
>> not be a show-stopper.
>>
>
> See 4) above, but if you are talking about a single database in a cluster
> streaming replication will not work for that.
>
>
>
>>
>> Thanks in advance
>> Olivier Gautherot
>> http://www.linkedin.com/in/ogautherot
>>
>
>
> --
> Adrian Klaver
> adrian(dot)klaver(at)aklaver(dot)com
>