Re: Adding LEFT JOIN to a query has increased execution time 10 times

>>>>> "Alexander" == Alexander Farber <alexander.farber@gmail.com> writes:
 Alexander> With the further help of the IRC folks the query has been
 Alexander> optimized (7-10 seconds -> 0.3 second)

0.3 MILLIseconds, actually.

(You chanced not to catch me around on IRC, but I see that didn't
matter.)

 Alexander> CREATE INDEX ON words_moves (gid, played DESC);
 Alexander> CREATE INDEX ON words_social (uid, stamp DESC);

I'm not a big fan of using DESC on indexes; it's almost never needed,
because any btree index can be scanned in reverse. (You only actually
need it if you're mixing ASC/DESC orderings in an ORDER BY and want an
index that matches it.)