Re: Default SELECT locking

From: Rob Calfee <trace_at_primenet.com>
Date: Tue, 14 Sep 1999 19:53:51 GMT
Message-ID: <37dea758.6877120@news.primenet.com>

You're right.

Readers don't block Readers
Readers don't block Writers
Writers don't block Readers

Writers block Writers (locked rows)

This is what I was told in an Oracle DBA class. Plus it makes sense regarding the rollback and recovery mechanisms in place.

Hope this helps and correct me, anyone, if I'm wrong.

On Tue, 14 Sep 1999 17:16:30 GMT, "Tom Williamson" <tom.williamson_at_home.com> wrote:

>This is a request for some "warm-and-fuzzy" reassurance information:
>
>I have written a number of SELECTs into PHP3-based web pages. These SELECTs
>return statistics about the information in our database, how many records,
>etc., etc.. Now that I've done all this work, it occurred to me
>(belatedly) that there might be some locking issues if the database was
>heavily used and one of these SELECTS hit a busy table.
>
>My question(s): I believe Oracle's default behavior is to have NO read
>locks when selecting data, is this correct? This would mean no locking
>problems, right? Is there a way to verify this in actual usage?
>
>Thanks in advance -
>
>Tom Williamson
>
>
>

Rob Calfee
DBA
rcalfee_at_incsystem.com Received on Tue Sep 14 1999 - 14:53:51 CDT