Hi,
Kevin:
Second machine config parameters:
shared_buffers = 8GB
work_mem = 1 GB (was 512MB)
maintenace_work_mem = 4 GB
#seq_page_cost = 1.0
#cpu_tuple_cost = 0.01
#cpu_index_tuple_cost = 0.005
#cpu_operator_cost = 0.0025
random_page_cost = 2.0
effective_cache_size = 110GB
I try to change from_collapse_limit, join_collapse_limit and io_con, w/o success.
I create a database with this tables only, vaccum analyze them and test with only my connection to postgresql.
Now we have another querys(all with aggregates) that the time is 15x - 20x slower than Oracle and SQL Server.
All tables have indexes (btree) with fields in the where/order/group parameters.
Maxim:
The developer is changing from a Desktop application (ODBC with Use Declare/Fetch, 'single' querys with local summing and aggregation) for a client/server web application (.NET, most querys with aggregate). Unfortunattly we cant change this querys, but I will try your solution to see what happens.
Take a look at another big query generated by the development tool. Oracle/SQL Server runs the same query (with the same data but in a slow machine) in about 2 seconds:
Best regards,
Alexandre
2015-08-05 14:24 GMT-03:00 Kevin Grittner <kgrittn@xxxxxxxxx>:
Alexandre de Arruda Paes <adaldeia@xxxxxxxxx> wrote:
> We did the following tests:
>
> 1) Postgresql 9.3 and Oracle 10 in a desktop machine(8 GB RAM, 1 SATA disk,Core i5)
> 2) Postgresql 9.3 in a server + FC storage (128 GB RAM, Xeon 32 cores, SAS disks)
That's only part of the information we would need to be able to
give specific advice. Please read this page:
https://wiki.postgresql.org/wiki/SlowQueryQuestions
One possibility is that you are running with the default
configuration, rather than having tuned for the hardware. You are
very likely to need to adjust shared_buffers, effective_cache_size,
work_mem, maintenance_work_mem, random_page_cost, cpu_tuple_cost,
and (at least for the second machine) effective_io_concurrency. If
the queries have a lot of joins you may need to increase
from_collapse_limit and/or join_collapse_limit. You also may need
to adjust [auto]vacuum and/or background writer settings. Various
OS settings may matter, too.
To get a handle on all this, it might be worth looking for Greg
Smith's book on PostgreSQL high performance.
--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
