Re: Major features for 9.1

From: Roy Hann
Subject: Re: Major features for 9.1
Date: ,
Msg-id: inij34$m4$1@speranza.aioe.org
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In response to: Re: Major features for 9.1  ("Kevin Grittner")
Responses: Re: Major features for 9.1  ("Kevin Grittner")
List: pgsql-advocacy

Tree view

Major features for 9.1  (Josh Berkus, )
 Re: Major features for 9.1  (Thom Brown, )
 Re: Major features for 9.1  ("Joshua D. Drake", )
 Re: Major features for 9.1  (Pavel Stehule, )
 Re: Major features for 9.1  (Guillaume Lelarge, )
  Re: Major features for 9.1  (phb07, )
 Re: Major features for 9.1  ("Kevin Grittner", )
  Re: Major features for 9.1  (Florian Weimer, )
 Re: Major features for 9.1  (Robert Bernier, )
  Re: Major features for 9.1  (David Fetter, )
 Re: Major features for 9.1  (Simon Riggs, )
  Re: Major features for 9.1  (Josh Berkus, )
   Re: Major features for 9.1  (Simon Riggs, )
    Re: Major features for 9.1  (Gilberto Castillo Martínez<>, )
    Re: Major features for 9.1  (David Fetter, )
   Re: Major features for 9.1  (Peter Eisentraut, )
    Re: Major features for 9.1  (David Fetter, )
     Re: Major features for 9.1  (Peter Eisentraut, )
   Re: Major features for 9.1  (Peter Eisentraut, )
    Re: Major features for 9.1  (Joshua Berkus, )
     Re: Major features for 9.1  (Andrew Lardinois, )
     Re: Major features for 9.1  ("Kevin Grittner", )
     Re: Major features for 9.1  (David Fetter, )
     Re: Major features for 9.1  (Greg Smith, )
      Re: Major features for 9.1  (Joshua Berkus, )
      Re: Major features for 9.1  (Bruce Momjian, )
    Re: Major features for 9.1  (Gilberto Castillo Martínez<>, )
   Re: Major features for 9.1  (Joshua Berkus, )
    Re: Major features for 9.1  (Peter Eisentraut, )
    Re: Major features for 9.1  (Oleg Bartunov, )
 Re: Major features for 9.1  (Emanuel Calvo, )
 Re: Major features for 9.1  ("Kevin Grittner", )
 Re: Major features for 9.1  ("Kevin Grittner", )
  Re: Major features for 9.1  (Jeff Davis, )
   Re: Major features for 9.1  ("Kevin Grittner", )
    Re: Major features for 9.1  (Oleg Bartunov, )
     Re: Major features for 9.1  (Gilberto Castillo Martínez<>, )
    Re: Major features for 9.1  (Jeff Davis, )
     Re: Major features for 9.1  ("Kevin Grittner", )
 Re: Major features for 9.1  ("Kevin Grittner", )
  Re: Major features for 9.1  (Gilberto Castillo Martínez<>, )
   Re: Major features for 9.1  ("Kevin Grittner", )
    Re: Major features for 9.1  (Andrew Lardinois, )
     Re: Major features for 9.1  ("Kevin Grittner", )
      Re: Major features for 9.1  ("Kevin Grittner", )
       Re: Major features for 9.1  (Andrew Lardinois, )
        Re: Major features for 9.1  ("Kevin Grittner", )
         Re: Major features for 9.1  (Andrew Lardinois, )
     Re: Major features for 9.1  (Simon Riggs, )
 Re: Major features for 9.1  (Aidan Van Dyk, )
 Re: Major features for 9.1  ("Kevin Grittner", )
  Re: Major features for 9.1  (Nikolas Everett, )
  Re: Major features for 9.1  (Josh Berkus, )
   Re: Major features for 9.1  ("Kevin Grittner", )
  Re: Major features for 9.1  (Roy Hann, )
   Re: Major features for 9.1  (Jeff Davis, )
    Re: Major features for 9.1  (Peter Eisentraut, )
     Re: Major features for 9.1  ("Kevin Grittner", )
  Re: Major features for 9.1  (Roy Hann, )
   Re: Major features for 9.1  ("Kevin Grittner", )
    Re: Major features for 9.1  (Jeff Davis, )
     Re: Major features for 9.1  ("Kevin Grittner", )
 Re: Major features for 9.1  ("Kevin Grittner", )
 Re: Major features for 9.1  (Peter Eisentraut, )
  Re: Major features for 9.1  (Magnus Hagander, )
   Re: Major features for 9.1  (Peter Eisentraut, )
 Re: Major features for 9.1  ("Kevin Grittner", )
  Re: Major features for 9.1  ("Joshua D. Drake", )
  Re: Major features for 9.1  (Greg Smith, )
   Re: Major features for 9.1  ("Kevin Grittner", )
    Re: Major features for 9.1  (Greg Smith, )
     Re: Major features for 9.1  ("Kevin Grittner", )
 Re: Major features for 9.1  (Simon Riggs, )
  Re: Major features for 9.1  (Joshua Tolley, )
   Re: Major features for 9.1  (Gilberto Castillo Martínez<>, )
   Re: Major features for 9.1  (Thomas Kellerer, )

Peter Eisentraut wrote:

> On ons, 2011-04-06 at 11:01 -0700, Jeff Davis wrote:
>> On Tue, 2011-04-05 at 14:57 +0000, Roy Hann wrote:
>> > Nikolas Everett wrote:
>> >
>> > > I think it is saying something that one of the most exciting features in 9.1
>> > > would be lost on a huge portion of the DB using public.  I've interviewed
>> > > DBAs who don't know what a transaction isolation level is.  Most of the
>> > > developers I've interviewed don't know.
>> >
>> > A DBA doesn't need to know what an isolation level is.  Programmers need
>> > to know.  (But they don't.)
>>
>> One of the use cases of SSI is to enforce constraints, which are
>> certainly of interest to DBAs.
>
> Well, but users can freely change the isolation level, so it would not
> really be an effective constraint mechanism.

We're getting O/T, but...

The checking of constraints is expected to be done using
serializable isolation regardless of the isolation level of the
transation that triggered it. See section 4.35.4 of the latest SQL
standard:

"Regardless of the isolation level of the SQL-transaction, phenomena
P1, P2, and P3 shall not occur during the implied reading of schema
definitions performed on behalf of executing an SQL-statement, the
checking of integrity constraints, and the execution of referential actions
associated with referential constraints."

A friend pointed this section out to me just a couple of days ago.

--
Roy



pgsql-advocacy by date:

From: Roy Hann
Date:
Subject: Re: Major features for 9.1
From: "Kevin Grittner"
Date:
Subject: Re: Major features for 9.1