Re: Support logical replication of DDLs

There's a bug in this patch, where if there are multiple publications
that publish ddls,
then multiple event triggers will write multiple WAL records.
This will result in duplicate ddls statements being published.
This will also create multiple WAL records.
To avoid this,
I've added a fix in event_trigger invoking logic
(EventTriggerCommonSetup()) patch-6,
to check for duplicate publication ddl deparsing event trigger functions
and if there are duplicates, only the first event trigger function is
invoked and the rest ignored.
This way, even if there are multiple publications that publish ddls,
then only one set
event trigger functions are invoked.

regards,
Ajin Cherian
Fujitsu Australia