Jeff Amiel becauseimj...@yahoo.com writes:
At the moment I think the only way to work around this is
to denormalize
your schema a bit.
And I feared as much.
It's biting me in other areas as well...this unusual distribution of
data...certain types of customers have completely different
Oddball data distribution giving me headaches.
We have a distinct 'customer' table with customer_id, type and name/demographic
information.
Assume some 1 million rows in the customer table.
We then have a customer 'relationship' table which simply contains 2
columns…designating parent and
-Original Message-
From: pgsql-general-ow...@postgresql.org
[mailto:pgsql-general-ow...@postgresql.org] On Behalf Of Jeff Amiel
Sent: Friday, December 02, 2011 3:20 PM
To: pgsql-general@postgresql.org
Subject: [GENERAL] Oddball data distribution giving me planner headaches
explain
--- On Fri, 12/2/11, David Johnston pol...@yahoo.com wrote:
From: David Johnston pol...@yahoo.com
What kind of plan does the following give?
EXPLAIN ANALYZE
SELECT *
FROM customer_rel p
JOIN customer c ON (p.parent_customer = c.customer_id)
WHERE c.customer_type = 'DISTRIBUTOR'
Nearly
-Original Message-
From: Jeff Amiel [mailto:becauseimj...@yahoo.com]
Sent: Friday, December 02, 2011 3:52 PM
To: pgsql-general@postgresql.org; David Johnston
Subject: RE: [GENERAL] Oddball data distribution giving me planner headaches
--- On Fri, 12/2/11, David Johnston pol...@yahoo.com
--- On Fri, 12/2/11, David Johnston pol...@yahoo.com wrote:
What happens if you disable, say, nested loops and/or index
scans?
planner selects different join/indexing techniques (query is slower) but row
estimates (bad) remain identical.
--
Sent via pgsql-general mailing list
-Original Message-
From: Jeff Amiel [mailto:becauseimj...@yahoo.com]
Sent: Friday, December 02, 2011 4:15 PM
To: pgsql-general@postgresql.org; David Johnston
Subject: RE: [GENERAL] Oddball data distribution giving me planner headaches
--- On Fri, 12/2/11, David Johnston pol
--- On Fri, 12/2/11, David Johnston pol...@yahoo.com wrote:
From: David Johnston pol...@yahoo.com
-
My, possibly naïve, observation:
So aside from the fact the estimates seem to be off the
planner has still
chosen the most
Jeff Amiel becauseimj...@yahoo.com writes:
Oddball data distribution giving me headaches.
[ 'distributor' customers have many more child customers than average ]
Does this oddball data distribution doom me to poor planning forever?
The only real fix for that will require cross-column
-Original Message-
From: Jeff Amiel [mailto:becauseimj...@yahoo.com]
Sent: Friday, December 02, 2011 5:07 PM
To: pgsql-general@postgresql.org; David Johnston
Subject: RE: [GENERAL] Oddball data distribution giving me planner headaches
--- On Fri, 12/2/11, David Johnston pol
--- On Fri, 12/2/11, David Johnston pol...@yahoo.com wrote:
Can you wrap the query into an SQL or PL/pgSQL function so
that, at least,
then planner will not be able to see the embedded plan info
in the outer
queries? You use-case
--- On Fri, 12/2/11, Tom Lane t...@sss.pgh.pa.us wrote:
The only real fix for that will require cross-column
statistics, which
we don't have yet --- without such, there's no way for the
planner to
know that distributors have an atypical number of child
customers.
I suspected as such.
--- On Fri, 12/2/11, Tom Lane t...@sss.pgh.pa.us wrote:
The only real fix for that will require cross-column
statistics, which
we don't have yet --- without such, there's no way for the
planner to
know that distributors have an atypical number of child
customers.
The only caveat that I
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