From: | "Mark Woodward" <pgsql(at)mohawksoft(dot)com> |
---|---|
To: | "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | pg(at)mohawksoft(dot)com, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: Netflix Prize data |
Date: | 2006-10-04 22:57:58 |
Message-ID: | 21735.24.91.171.78.1160002678.squirrel@mail.mohawksoft.com |
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Lists: | pgsql-hackers |
> "Mark Woodward" <pgsql(at)mohawksoft(dot)com> writes:
>> The one thing I notice is that it is REAL slow.
>
> How fast is your disk? Counting on my fingers, I estimate you are
> scanning the table at about 47MB/sec, which might or might not be
> disk-limited...
>
>> I'm using 8.1.4. The "rdate" field looks something like: "2005-09-06"
>
> So why aren't you storing it as type "date"?
>
You are assuming I gave it any thought at all. :-)
I converted it to a date type (create table ratings2 as ....)
markw(at)snoopy:~/netflix/download$ time psql -c "select count(*) from
ratings" netflix
count
-----------
100480507
(1 row)
real 1m29.852s
user 0m0.002s
sys 0m0.005s
That's about the right increase based on the reduction in data size.
OK, I guess I am crying wolf, 47M/sec isn't all that bad for the system.
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