RE: Do selects block truncates?
- From: genegurevich@xxxxxxxxxxxx
- To: ukja.dion@xxxxxxxxx
- Date: Fri, 21 Dec 2007 09:52:54 -0600
Ukja,
I just posted a possible explanation to the list - the truncate is
considered a DDL and select would block other
DDL statements to prevent the table structure from being changed during the
execution.
thank you
Gene Gurevich
Oracle MySQL Operations - OMO
224-405-4079
"Ukja.dion"
<ukja.dion@gmail.
com> To
Sent by: "'Kurt Franke'"
oracle-l-bounce@f <Kurt-Franke@xxxxxx>, "'oracle-l'"
reelists.org <oracle-l@xxxxxxxxxxxxx>
cc
12/21/2007 09:34 Subject
AM RE: Do selects block truncates?
Please respond to
ukja.dion@xxxxxxx
om
>this is never a bug but is the consequence of enforcing statement-level
read consistency
>which is always guranteed by oracle.
Can you explain in more detail?
Which relationship does read consistency mechanism have with the blocking
of truncate by select operation?
I don't know no concept of "select" blocking any kind of operation in
Oracle.
(except some internal lightweight locks like latch or buffer lock, library
cache lock/pin, blah blah blah)
-----Original Message-----
From: Kurt Franke [mailto:Kurt-Franke@xxxxxx]
Sent: Friday, December 21, 2007 10:35 PM
To: 'oracle-l'; ukja.dion@xxxxxxxxx
Subject: RE: Do selects block truncates?
Hi,
...
>
> If select really blocks truncate, it's a amazing bug. :)
>
this is never a bug but is the consequence of enforcing statement-level
read consistency
which is always guranteed by oracle.
the only exception from this mechanism is the complete refresh of a
materialized view with
"atomic_refresh => FALSE" which then does the truncate wether or not any
select is runnig
on the materialized view. active select on the materialized view will break
then with
ORA-08103
regards
kf
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