Re: continuous copy/update one table to another

From: John R Pierce <pierce(at)hogranch(dot)com>
To: Terry <td3201(at)gmail(dot)com>
Cc: PostgreSQL <pgsql-general(at)postgresql(dot)org>
Subject: Re: continuous copy/update one table to another
Date: 2010-02-28 22:32:03
Message-ID: 4B8AEEE3.9050806@hogranch.com
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Terry wrote:
> Hello,
>
> I am looking for a way to copy all the data from one table to another
> on a regular basis, every 5 minutes let's say.
>
> INSERT INTO table2 SELECT * FROM table1;
>
> The above will copy all the data as is and insert it into the other
> table. What happens if I rerun it again? Will it just append table1
> again into table2? How can I have it only insert rows that are
> different? Would that be a program to lookup the most last record in
> table 1 and then a query to only select after that row for the insert
> into table2?
>
>

both tables should have a serial 'id' (or bigserial if you expect over 2
billion entries), and use something like ...


insert into table2 select * from table1 as t1 where t1.id >
(select max(t.id) from table2 as t);

i haven't tested this but I think it should work. as long as id is
indexed in both tables

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