Hello everybody,
I have a simple query which selects data from not very large table (
434161 rows) and takes far more time than I'd expect. I believe it's
due to a poor disk performance because when I execute the very same
query for a second time I get much better results (caching kicks in?).
Can
Martin Chlupac wrote:
Hello everybody,
I have a simple query which selects data from not very large table (
434161 rows) and takes far more time than I'd expect. I believe it's
due to a poor disk performance because when I execute the very same
query for a second time I get much better results
Suppose I have a large table with a small-cardinality CATEGORY column (say,
categories 1..5). I need to sort by an arbitrary (i.e. user-specified) mapping
of CATEGORY, something like this:
1 = 'z'
2 = 'a'
3 = 'b'
4 = 'w'
5 = 'h'
So when I get done, the sort order should be 2,3,5,4,1.
I
On Thu, Jul 9, 2009 at 5:26 PM, Craig Jamescraig_ja...@emolecules.com wrote:
Suppose I have a large table with a small-cardinality CATEGORY column (say,
categories 1..5). I need to sort by an arbitrary (i.e. user-specified)
mapping of CATEGORY, something like this:
1 = 'z'
2 = 'a'
3 =
[ Attempting to resend, because it didn't seem to get through last time. ]
We have a query that runs very slowly on our 8.3 database. (I can't
tell you exactly how slowly, because it has never successfully run to
completion even when we left it running overnight.) On the 8.4
database on my
=?UTF-8?Q?Grzegorz_Ja=C5=9Bkiewicz?= gryz...@gmail.com writes:
On Thu, Jul 9, 2009 at 5:26 PM, Craig Jamescraig_ja...@emolecules.com wrote:
Suppose I have a large table with a small-cardinality CATEGORY column (say,
categories 1..5). Â I need to sort by an arbitrary (i.e. user-specified)
Craig James craig_ja...@emolecules.com wrote:
Suppose I have a large table with a small-cardinality CATEGORY
column (say, categories 1..5). I need to sort by an arbitrary
(i.e. user-specified) mapping of CATEGORY
There was a recent thread discussing ways to do that:
On Thu, Jul 9, 2009 at 6:26 PM, Craig Jamescraig_ja...@emolecules.com wrote:
Suppose I have a large table with a small-cardinality CATEGORY column (say,
categories 1..5). I need to sort by an arbitrary (i.e. user-specified)
mapping of CATEGORY, something like this:
1 = 'z'
2 = 'a'
3 =
Robin Houston escribió:
We have a query that runs very slowly on our 8.3 database. (I can't
tell you exactly how slowly, because it has never successfully run to
completion even when we left it running overnight.) On the 8.4
database on my laptop, it runs in about 90 seconds. Of course there
Robin Houston robin.hous...@gmail.com writes:
We have a query that runs very slowly on our 8.3 database. (I can't
tell you exactly how slowly, because it has never successfully run to
completion even when we left it running overnight.) On the 8.4
database on my laptop, it runs in about 90
I noticed a bit of a performance regression in embedded sql queries when
moving from the client libraries in verison 8.2.4 to 8.3.7. My
application does a whole lot of queries, many of which don't return any
data. When we moved to the new libraries the time of running a query
(from the
From: pgsql-performance-ow...@postgresql.org
[mailto:pgsql-performance-
ow...@postgresql.org] On Behalf Of Robin Houston
Sent: Thursday, July 09, 2009 12:35 PM
We have a query that runs very slowly on our 8.3 database. (I can't
tell you exactly how slowly, because it has never successfully
On Thu, Jul 09, 2009 at 09:26:42AM -0700, Craig James wrote:
Suppose I have a large table with a small-cardinality CATEGORY column (say,
categories 1..5). I need to sort by an arbitrary (i.e. user-specified)
mapping of CATEGORY, something like this:
1 = 'z'
2 = 'a'
3 = 'b'
4 = 'w'
On Thu, Jul 09, 2009 at 09:26:42AM -0700, Craig James wrote:
You can do it like this:
select c.*
from categories c, ( values (1, 'z'), (2, 'a'), (3, 'b'), (4, 'w'),
(5,
'h') ) as o (id, ordering) on c.id = o.id
order by o.ordering
Another option would be:
select c.*
from categories c
order
2009/7/9 Tom Lane t...@sss.pgh.pa.us:
=?UTF-8?Q?Grzegorz_Ja=C5=9Bkiewicz?= gryz...@gmail.com writes:
On Thu, Jul 9, 2009 at 5:26 PM, Craig Jamescraig_ja...@emolecules.com
wrote:
Suppose I have a large table with a small-cardinality CATEGORY column (say,
categories 1..5). I need to sort by
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