Re: [HACKERS] Detecting schema changes during logical replication

On Sun, May 7, 2017 at 8:04 PM, Andres Freund <andres@anarazel.de> wrote:
> Hi,
>
> On 2017-05-07 19:27:08 +0100, Daniele Varrazzo wrote:
>> I'm putting together a replication system based on logical
>> replication.
>
> Interesting.  If you very briefly could recap what it's about... ;)

I need to replicate some tables from a central database into the
database that should run a secondary system. For a similar use case we
have used Londiste in the past, which has served us good, but its
usage has not been problem-free. Logical decoding seems much less
invasive on the source database than a trigger-based replication
solution, and has less moving part to care about and maintain.

For the moment I'm hacking into a fork of Euler project for wal
decoding into json (https://github.com/dvarrazzo/wal2json), mostly
adding configurability, so that we may be able to replicate only the
tables we need, skip certain fields etc. I'm also taking a look at
minimising the amount of information produced: sending over and over
the column names and types for every record seems a waste, hence my
question.