To be frank, there is so much wrong with this query that it is hard to know where to start. But a few top items:
* Make sure all of the tables involved have been analyzed. You might want to bump default_statistics_target up and see if that helps.
* As mentioned already, increase work_mem, as you have things spilling to disk (e.g. external merge Disk: 36280kB)
* Don't use the "FROM table1, table2, table3" syntax but use "FROM table1 JOIN table2 ON (...) JOIN table3 ON (...)
* Try not to use subselects. Things like WHERE x IN (SELECT ...) are expensive and hard to optimize.
* You have useless GROUP BY clauses in there. Remove to simplify the query
* There is no LIMIT. Does the client really need all 135,214 rows?
Cheers,
Greg
