Re: simple question

From: Kenneth Koenraadt <plovmand_at_hotmail.com>
Date: Sat, 10 Mar 2001 18:10:36 GMT
Message-ID: <3aaa6c08.1145111@news.mobilixnet.dk>

Hi Jade,

Since a select statement does not implicitly lock the table, 2 or more processes can easily read a table concurrenly.

Oracle has, however, something called "latches" : When a row is read by a process, it issues a "latch" on it for a *very* limited time, so that no other process can access it. So if MANY processes try to read the row, some of them may wait for their turn/latch.

If processes wait unacceptably long for a latched row, it is called latch contention. But it should not happen in a correctly configured system.

Kenneth Koenraadt plovmand@<no-spam>hotmail.com

On Sun, 11 Mar 2001 01:04:39 +0800, "Jade Fox" <ballsuen_at_yahoo.com> wrote:

>I'm accessing the oracle database through jdbc.
>If two processes are selecting data from a table at the same time, is it a
>concurrent process or one process need to wait until another finish?
>
>
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Received on Sat Mar 10 2001 - 12:10:36 CST