Re: Query Performance SQL Server vs. Postgresql

I have to concur. Sql is written specifially and only for Windows. It is
optimized for windows. Postgreal is writeen for just about everything
trying to use common code so there isn't much optimization because it has to
be optimized based on the OS that is running it. Check out your config and
send it to us. That would include the OS and hardware configs for both
machines.

On Wed, Nov 17, 2010 at 3:47 PM, Tomas Vondra <tv(at)fuzzy(dot)cz> wrote:

> Dne 17.11.2010 05:47, Pavel Stehule napsal(a):
> > 2010/11/17 Humair Mohammed <humairm(at)hotmail(dot)com>:
> >>
> >> There are no indexes on the tables either in SQL Server or Postgresql -
> I am
> >> comparing apples to apples here. I ran ANALYZE on the postgresql tables,
>
> Actually no, you're not comparing apples to apples. You've provided so
> little information that you may be comparing apples to cucumbers or
> maybe some strange animals.
>
> 1) info about the install
>
> What OS is this running on? I guess it's Windows in both cases, right?
>
> How nuch memory is there? What is the size of shared_buffers? The
> default PostgreSQL settings is very very very limited, you have to bump
> it to a much larger value.
>
> What are the other inportant settings (e.g. the work_mem)?
>
> 2) info about the dataset
>
> How large are the tables? I don't mean number of rows, I mean number of
> blocks / occupied disk space. Run this query
>
> SELECT relname, relpages, reltuples, pg_size_pretty(pg_table_size(oid))
> FROM pg_class WHERE relname IN ('table1', 'table2');
>
> 3) info about the plan
>
> Please, provide EXPLAIN ANALYZE output, maybe with info about buffers,
> e.g. something like
>
> EXPLAIN (ANALYZE ON, BUFFERS ON) SELECT ...
>
> 4) no indexes ?
>
> Why have you decided not to use any indexes? If you want a decent
> performance, you will have to use indexes. Obviously there is some
> overhead associated with them, but it's premature optimization unless
> you prove the opposite.
>
> BTW I'm not a MSSQL expert, but it seems like it's building a bitmap
> index on the fly, to synchronize parallelized query - PostgreSQL does
> not support that.
>
> regards
> Tomas
>
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