Thanks guys
Lesson learned
On Tue, 4 Sep 2007, Scott Marlowe wrote:
On 8/31/07, Richard Ray <[EMAIL PROTECTED]> wrote:
Changing to enable_seqscan = on does solve this problem, thanks
Is there some method of crafting a query that will assert my wishes to the
planner
When is enable_seqscan = o
On 8/31/07, Richard Ray <[EMAIL PROTECTED]> wrote:
> Changing to enable_seqscan = on does solve this problem, thanks
> Is there some method of crafting a query that will assert my wishes to the
> planner
> When is enable_seqscan = off appropriate
enable_xxx = off are troubleshooting tools. They
Richard Ray wrote:
When is enable_seqscan = off appropriate
Never(*)
It's not for normal usage, the various enable_xxx settings do let you
experiment with different options if you think the planner is making a
mistake.
(*) OK, sooner or later, if you have enough systems and enough
perfor
On Fri, 31 Aug 2007, Tom Lane wrote:
Richard Ray <[EMAIL PROTECTED]> writes:
On Fri, 31 Aug 2007, Michael Glaesemann wrote:
EXPLAIN ANALYZE will help you see what the planner is doing to produce the
results.
mda=# EXPLAIN ANALYZE select * from t1 where length(bar) = 0 order by foo;
Michael Glaesemann <[EMAIL PROTECTED]> writes:
> On Aug 31, 2007, at 16:07 , Richard Ray wrote:
>>> If length(bar) = 0 is a common operation on this table, you might
>>> consider using an expression index on t1:
>>
>>> create index t1_length_bar_idx on t1 (length(bar));
>>
>> This is a one time
Richard Ray <[EMAIL PROTECTED]> writes:
> On Fri, 31 Aug 2007, Michael Glaesemann wrote:
>> EXPLAIN ANALYZE will help you see what the planner is doing to produce the
>> results.
> mda=# EXPLAIN ANALYZE select * from t1 where length(bar) = 0 order by foo;
>
On Aug 31, 2007, at 16:07 , Richard Ray wrote:
Total runtime: 2349614.258 ms
(3 rows)
Wow. Nearly 40 minutes! What are your work_mem set at? You may want
to increase work_mem, as it might help with the sort.
The index for foo on t1 is the primary index t1_pkey
Why is it slower using the
On Fri, 31 Aug 2007, Michael Glaesemann wrote:
On Aug 31, 2007, at 13:32 , Richard Ray wrote:
"select * from t1 where length(bar) = 0;" runs about 2 minutes
"select * from t1 where length(bar) = 0 order by foo ;" ran until I
stopped it after about 20 minutes
EXPLAIN ANALYZE will help you s
On Aug 31, 2007, at 13:32 , Richard Ray wrote:
"select * from t1 where length(bar) = 0;" runs about 2 minutes
"select * from t1 where length(bar) = 0 order by foo ;" ran until I
stopped it after about 20 minutes
EXPLAIN ANALYZE will help you see what the planner is doing to
produce the res
I have a table, t1, with about 12 million rows
The column foo is unique and indexed
The column bar is not unique and is indexed
"select * from t1 where length(bar) = 0;" runs about 2 minutes
"select * from t1 where length(bar) = 0 order by foo ;" ran until I
stopped it after about 20 minutes
My s
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