Re: How to "unique-ify" HUGE table?

On Tue, 23 Dec 2008 12:25:48 -0500
"Kynn Jones" <kynnjo(at)gmail(dot)com> wrote:
> Hi everyone!
> I have a very large 2-column table (about 500M records) from which I want to
> remove duplicate records.
>
> I have tried many approaches, but they all take forever.
>
> The table's definition consists of two short TEXT columns. It is a
> temporary table generated from a query:
>
> CREATE TEMP TABLE huge_table AS SELECT x, y FROM ... ;
>
> Initially I tried
>
> CREATE TEMP TABLE huge_table AS SELECT DISTINCT x, y FROM ... ;
>
> but after waiting for nearly an hour I aborted the query, and repeated it

Do you have an index on x and y? Also, does this work better?

CREATE TEMP TABLE huge_table AS SELECT x, y FROM ... GROUP BY x, y;

What does ANALYZE EXPLAIN have to say?

--
D'Arcy J.M. Cain <darcy(at)druid(dot)net> | Democracy is three wolves
http://www.druid.net/darcy/ | and a sheep voting on
+1 416 425 1212 (DoD#0082) (eNTP) | what's for dinner.