row wise comparison broken

Tatsuo Ishii <t-ishii@sra.co.jp> writes:

I guess this means that PostgreSQL does not fully support SQL's
row-wise comparison. We need to add this to the TODO list?

I thought it was there already ... certainly this has been discussed
before ...

regards, tom lane

Tatsuo Ishii <t-ishii@sra.co.jp> writes:

I guess this means that PostgreSQL does not fully support SQL's
row-wise comparison. We need to add this to the TODO list?

I thought it was there already ... certainly this has been discussed
before ...

This was discussed (including a possible implementation of the correct
behavior) at some length on the performance list a little over a month
ago. I don't think it made it to Bruce who probably would have added to
the todo list...the consensus was the current behavior is wrong but
there were some concerns about backwards compatibility.

Merlin

Tatsuo Ishii <t-ishii@sra.co.jp> writes:

I guess this means that PostgreSQL does not fully support SQL's
row-wise comparison. We need to add this to the TODO list?

I thought it was there already ... certainly this has been discussed
before ...

This was discussed (including a possible implementation of the correct
behavior) at some length on the performance list a little over a month
ago. I don't think it made it to Bruce who probably would have added to
the todo list...the consensus was the current behavior is wrong but

Yes, I found the following thread started by you in the
pgsql-performance list:

Subject: [PERFORM] best way to fetch next/prev record based on index
Date: Tue, 27 Jul 2004 06:18:43 -0700

there were some concerns about backwards compatibility.

IMO 8.0 is a good chance to fix it. Maybe we could add a GUC switch to
fall back to pre-8.0 behavior...
--
Tatsuo Ishii

Tatsuo Ishii wrote:

Tatsuo Ishii <t-ishii@sra.co.jp> writes:

I guess this means that PostgreSQL does not fully support SQL's
row-wise comparison. We need to add this to the TODO list?

I thought it was there already ... certainly this has been discussed
before ...

This was discussed (including a possible implementation of the correct
behavior) at some length on the performance list a little over a month
ago. I don't think it made it to Bruce who probably would have added to
the todo list...the consensus was the current behavior is wrong but

Yes, I found the following thread started by you in the
pgsql-performance list:

Subject: [PERFORM] best way to fetch next/prev record based on index
Date: Tue, 27 Jul 2004 06:18:43 -0700

there were some concerns about backwards compatibility.

IMO 8.0 is a good chance to fix it. Maybe we could add a GUC switch to
fall back to pre-8.0 behavior...

I remember the thread but didn't see a TODO in there at the time.

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

Bruce Momjian <pgman@candle.pha.pa.us> writes:

I remember the thread but didn't see a TODO in there at the time.

* Make row-wise comparisons work per SQL spec

regards, tom lane

Yes, I found the following thread started by you in the
pgsql-performance list:

Subject: [PERFORM] best way to fetch next/prev record based on index
Date: Tue, 27 Jul 2004 06:18:43 -0700

there were some concerns about backwards compatibility.

IMO 8.0 is a good chance to fix it. Maybe we could add a GUC switch to
fall back to pre-8.0 behavior...
--
Tatsuo Ishii

Here is a link to Tom's thoughts on possible approaches to implementing
a fix, and why this is A Lot More Complicated Than It Seems (tm),
particularly if taken to the next logical step where the planner could
make use of the row-wise comparison to make more intelligent decisions
about index selection.

http://archives.postgresql.org/pgsql-performance/2004-07/msg00218.php

Still, I think the current behavior is wrong...and is exactly the kind
of trick question that a sql compliance benchmark might ask.

Merlin

"Merlin Moncure" <merlin.moncure@rcsonline.com> writes:

http://archives.postgresql.org/pgsql-performance/2004-07/msg00218.php

Still, I think the current behavior is wrong...and is exactly the kind
of trick question that a sql compliance benchmark might ask.

It undoubtedly is wrong. But it has been wrong forever, or at least
since Tom Lockhart put in the syntax, back in 1997. We've gotten few
complaints --- which means to me that this is not a high-priority bug
fix. I think we should leave it as a to-do item for a future release
cycle, rather than implement some hasty solution for 8.0.

regards, tom lane

Added to TODO:

* Make row-wise comparisons work per SQL spec

---------------------------------------------------------------------------

Tom Lane wrote:

"Merlin Moncure" <merlin.moncure@rcsonline.com> writes:

http://archives.postgresql.org/pgsql-performance/2004-07/msg00218.php

Still, I think the current behavior is wrong...and is exactly the kind
of trick question that a sql compliance benchmark might ask.

It undoubtedly is wrong. But it has been wrong forever, or at least
since Tom Lockhart put in the syntax, back in 1997. We've gotten few
complaints --- which means to me that this is not a high-priority bug
fix. I think we should leave it as a to-do item for a future release
cycle, rather than implement some hasty solution for 8.0.

regards, tom lane

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-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073