I was thinking about creating a trigger on every table that would write an
insert, update, or delete statement into a log file. Each replicated
database would pro-actively read these and post them.
-----Original Message-----
From: Thomas Antepoth [SMTP:t_antepoth@hamm.netsurf.de]
Sent: Monday, February 15, 1999 9:16 PM
To: pgsql-general@postgreSQL.org
Subject: Re: [GENERAL] Replication of databases (esp.
postgres)
Dustin,
thank you for your answer.
On Mon, 15 Feb 1999, dustin sallings wrote:
> // {Replication of r/w Databases in a two pass scheme w/
renumbering}
> Just one note. Renumbering isn't all that important. I did
one
> that had a non-numeric unique ID for identity type columns.
I thought of a field named db_id. This field combined with
a unique (at least to the local database) counter should give a
unique index to each relation.
The rule to follow is: Every record in a relation with the
same db_id and the same rec_id belongs together.
But think of this situation:
DB 1 gets a relation.
table1 table2
record1 record1
record2
Now this relation gets replicated to DB 2.
After this is done, DB 2 adds a record3 to
table2 this relation.
Question: Which db_id should DB 2 use?
His own? In this way record3 wouldn't belong
to this relation.
The id of DB 1? In this way the data may
not be unique to DB 1 as DB 1 might enter
the same values for record3 for a completely
other relation and a collision is created.
So i dropped the idea of having a db_id field
to identify the record of a relation w/o
renumbering the relations by a master.
have a nice day! t++
