Does PostgreSQL optimizer handle iceberg queries well?
What do you mean by iceberg query ?
I've never heard this term.
Regards, Christoph
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I'm wondering if PostgreSQL actually reparses the view definition on
each invocation or if it stores the required information in some
accessible place.
The documentation says:
Whenever a query against a view (i.e. a virtual table) is made, the
rewrite system rewrites the user's query to
See the developers FAQ for URL's.
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Les Hazlewood wrote:
Does anyone have a definitive BNF grammar of SQL99 or SQL92? (I'd prefer 99
but I'll take what I can get ;)
I'm trying to make a simplified XML to SQL
It is a query that looks like
SELECT target1, target2... targetn, SUN(t.qty)
FROM Table t
GROUP BY target1
HAVING SUM(t.qty)=10
You can replace SUM(t.qty)=10 with other aggregate constraints.
- Original Message -
From: Christoph Haller
To: [EMAIL PROTECTED]
Cc: [EMAIL PROTECTED]
On Tue, Feb 04, 2003 at 09:08:56 -0500,
Wei Weng [EMAIL PROTECTED] wrote:
It is a query that looks like
SELECT target1, target2... targetn, SUN(t.qty)
FROM Table t
GROUP BY target1
HAVING SUM(t.qty)=10
You can replace SUM(t.qty)=10 with other aggregate constraints.
There were some
Lex Berezhny wrote:
hi,
I'm trying to write some code that can analyze the database structure
and i need a way to discover the composition of a view (the tables and
table.column info).
I've managed to do much of this by querying the pg_views for the
definition and literally parsing
Christoph Haller wrote:
Does PostgreSQL optimizer handle iceberg queries well?
What do you mean by iceberg query ?
I've never heard this term.
Iceberg queries compute one or more aggregate functions to find
aggregate values above a specified threshold. A typical iceberg query
would be
Jan Wieck [EMAIL PROTECTED] writes:
As to the original question, if an index is available that returns the
rows in the sort order of the GROUP BY clause, PostgreSQL defaults to an
index scan, otherwise it will do a sort of the rows matching an optional
WHERE clause. This sorted set is then
Jan Wieck [EMAIL PROTECTED] writes:
Lex Berezhny wrote:
My goal is to take a view name as input and output the tables and
columns composing the view.
Don't forget that a view's columns can contain complex expressions
instead of simple table.column references.
Yes. This problem is not
Hello,
I'm currently in the midst of working on a serializable transaction
which drops indexes on several tables, does a bulk copy, and rebuilds
the indexes. Based on what I've read it seemed as though I'd be able to
concurrently execute read only queries against these tables, returning
Tom Lane wrote:
Jan Wieck [EMAIL PROTECTED] writes:
As to the original question, if an index is available that returns the
rows in the sort order of the GROUP BY clause, PostgreSQL defaults to an
index scan, otherwise it will do a sort of the rows matching an optional
WHERE clause. This
justin [EMAIL PROTECTED] writes:
I'm currently in the midst of working on a serializable transaction
which drops indexes on several tables, does a bulk copy, and rebuilds
the indexes. Based on what I've read it seemed as though I'd be able to
concurrently execute read only queries against
I have a table which defines various possible file delimiters (CHAR(1) NOT
NULL), for the moment it'll only contain comma and tab. Inserting a comma is
easy, but inserting a tab is proving somewhat more difficult.
How do I do it in 'psql'?
Luke Pascoe.
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Hi Luke.
On Wednesday, February 5, 2003, at 02:39 PM, Luke Pascoe wrote:
I have a table which defines various possible file delimiters (CHAR(1)
NOT
NULL), for the moment it'll only contain comma and tab. Inserting a
comma is
easy, but inserting a tab is proving somewhat more difficult.
How
--- Luke Pascoe [EMAIL PROTECTED] wrote:
I have a table which defines various possible file
delimiters (CHAR(1) NOT
NULL), for the moment it'll only contain comma and
tab. Inserting a comma is
easy, but inserting a tab is proving somewhat more
difficult.
How do I do it in 'psql'?
--
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