hope I understand the planner behavior for
my queries better now.
Regards,
Milan Zamazal
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> "PS" == Pavel Stehule writes:
PS> and value efective_cache_size ???
effective_cache_size = 128MB
PS> what is CREATE INDEX stament for index?
create index foo2_value_idx on foo2(value);
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> "PS" == Pavel Stehule writes:
PS> Have you original values random_page_cost and seq_page_cost in
PS> postgres.conf?
Yes. To be sure I uncommented the values in postgresql.conf
seq_page_cost = 1.0 # measured on an arbitrary scale
random_page_cost = 4.0
> "GJ" == Grzegorz Jaśkiewicz writes:
GJ> Do you seriously need to walk the user through couple of million
GJ> rows of data ?
Typically not. Data can be of any size. Some tables may be large and
I'd like to understand what happens. It is a general data browser.
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> "AL" == Albe Laurenz writes:
AL> Did you try to reduce the cursor_tuple_fraction parameter?
No, good idea, thanks. It helps.
The question is whether it's a good idea to reduce cursor_tuple_fraction
universally, without knowing the table size before (and I'm not going to
use SELECT CO
> "PS" == Pavel Stehule writes:
PS> please EXPLAIN ANALYZE Pavel
I see, I'm sorry. Here are the results:
set enable_seqscan = on;
explain analyze declare c cursor for select * from foo2 order by value;
QUERY PLAN
QUERY PLAN
-
Index Scan using foo2_value_idx on foo2 (cost=0.00..32220140.73
rows=999 width=10)
(1 row)
Regards,
Milan Zamazal
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>>>>> "FR" == Filip Rembiałkowski writes:
FR> 2010/1/5 Milan Zamazal
>> - Is it a good idea to set enable_seqscan or enable_sort to "off"
>> globally in my case? Or to set them to "off" just before working
>&
My problem is that retrieving sorted data from large tables is sometimes
very slow in PostgreSQL (8.4.1, FWIW).
I typically retrieve the data using cursors, to display them in UI:
BEGIN;
DECLARE ... SELECT ... ORDER BY ...;
FETCH ...;
...
On a newly created table of about 10 million rows
