Hi, I seem to recall that in Oracle you load into specific partitions
without specifically naming them in insert statements (in other words you
insert into table, the engine redirects data to the corrisponding
partition), I quickly looked at postgresql partitioning and it seems to me
that you need to insert into a specified derived table (unless you set up
rules).
It would be good to have an insert behaviour similar to Oracle by default.
Also I see that the original table is always scanned, partition exclusion
happens only on the derived tables, is this correct?
Regards
paolo
-Messaggio originale-
Da: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] conto di Simon Riggs
Inviato: venerdì 23 settembre 2005 11.51
A: Jim C. Nasby
Cc: Tom Lane; pgsql-hackers@postgresql.org
Oggetto: Re: [HACKERS] Table Partitioning is in 8.1
On Thu, 2005-09-22 at 14:37 -0500, Jim C. Nasby wrote:
On Thu, Sep 22, 2005 at 10:11:50AM +0100, Simon Riggs wrote:
On Wed, 2005-09-21 at 15:39 -0400, Tom Lane wrote:
Simon Riggs [EMAIL PROTECTED] writes:
Is it possible that the Release Notes do not fully explain the
Constraint Exclusion feature? Or is it the consensus that
it works but
not quite well enough to make a song and dance about yet?
I hardly think that the existing constraint-exclusion code
is enough for
us to claim we support table partitioning. There's too much grunt
work that the DBA still has to do to set up a partitioning
arrangement.
So you think the DBA can do partitioning? Good.
Setting up partitioning in Oracle or SQLServer2005 requires lots of
syntax and multiple commands. There are fewer commands with PostgreSQL
and they are ISO/ANSI compliant also.
Actually, IIRC it takes 2 commands; one to initially setup the
partitioning and one to create new partitions as needed. 3 commands if
you count DROP PARTITON.
Which is what it takes in PostgreSQL.
It's been a while since I looked at what you've done, but I seem to
recall needing to manually maintain rules every time you create a new
partition.
All current implementations I am aware of require Declarative statements
each time a new partition is started.
But there is no *need* to create RULEs. You would need to do that if you
wanted automatic routing of INSERT statements. The current PostgreSQL
implementation does not do this, and yes, this would require creating a
set of Rule statements to do this - though possible to do this
automatically with a simple script. My experience with Oracle has been
that one loads into specifically identified partitions, so the loading
case for PostgreSQL is essentially identical to the common case for
Oracle. My experience may not be everybody's, so I may be off-base on
this, but I've not put a priority on solving that issue. Do people
consider that aspect essential to the wider use of partitioning?
I don't consider CE to be complete, any more than any newly introduced
major feature set, but IMHO the important first order functionality is
now available in PostgreSQL.
I'm looking at probably Tuesday to submit first draft docs.
Best Regards, Simon Riggs
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