Re: 9i streams vs triggers

From: Mark Townsend <markbtownsend_at_attbi.com>
Date: Fri, 10 Jan 2003 15:48:12 GMT
Message-ID: <BA442B14.5836%markbtownsend@attbi.com>

in article avmkgh$6kq$1_at_gabriel.uhc.com, servant at mjohns1_at_uhc.com wrote on 1/10/03 6:14 AM:

> The update
> will lock the row and block the select and vice versa, right?

Nope - welcome to Oracle. Repeat after me - "readers don't block writers, writers don't block readers". It's a little complicated, but basically Oracle reads are not blocked by writes to the data (an older version of the row(s) are used), and Oracle also doesn't take out read locks like other databases do.

> What I meant by replication is logical hot standby so I think we agree
> there. That solves the contention issue but does not address the complexity
> issue.

The thinking here is not clear also - logical standby is still doing the same amount of DML on the standby system, so if DML WAS going to block your queries on the production, the 'replicated' DML would also block the queries on the standby. Received on Fri Jan 10 2003 - 09:48:12 CST