seems similar to this problem: http://stackoverflow.com/questions/5198380/improving-postgres-psycopg2-query-performance-for-python-to-the-same-level-of-ja but no solution yet. On Thu, Jan 12, 2012 at 5:00 PM, Yan Chunlu <springrider@xxxxxxxxx> wrote: > I also tried explain but found nothing special: > > explain select * from data_table where thing_id in > (164438,112478,102941,112377,164442,181764,104028); > QUERY PLAN > ------------------------------------------------------------------------------------------------------- > Bitmap Heap Scan on data_table (cost=31.75..579.10 rows=141 width=53) > Recheck Cond: (thing_id = ANY > ('{164438,112478,102941,112377,164442,181764,104028}'::bigint[])) > -> Bitmap Index Scan on idx_data_table (cost=0.00..31.71 rows=141 width=0) > Index Cond: (thing_id = ANY > ('{164438,112478,102941,112377,164442,181764,104028}'::bigint[])) > > > > On Thu, Jan 12, 2012 at 4:47 PM, Yan Chunlu <springrider@xxxxxxxxx> wrote: >> I am transforming a db with millions records to anther schema. for >> some reason I need to select the records using IN (xx,xx). >> >> the ids in the IN was about 1000 recored every time, but I found the >> query was getting slow while the selection moving on. >> >> the shared buffer is 2048M. and the cpu and io usage is as normal. >> >> But while I am processing a smaller db on another machine, which only >> has the default 24MB, the selection went very smooth. >> >> >> here is the logs: >> >> start... 0 limit:1000 >> selection time: 0.140721082687 >> sort_options >> msgtime >> start... 1000 limit:1000 >> selection time: 0.122759103775 >> start... 2000 limit:1000 >> selection time: 0.150802850723 >> start... 3000 limit:1000 >> selection time: 0.173918008804 >> start... 4000 limit:1000 >> selection time: 0.212812900543 >> start... 5000 limit:1000 >> selection time: 0.255054950714 >> start... 6000 limit:1000 >> selection time: 0.230540037155 >> start... 7000 limit:1000 >> selection time: 0.24426317215 >> start... 8000 limit:1000 >> selection time: 0.326669931412 >> start... 9000 limit:1000 >> selection time: 0.351358175278 >> start... 10000 limit:1000 >> selection time: 0.386382102966 >> start... 11000 limit:1000 >> selection time: 0.440491914749 >> start... 12000 limit:1000 >> selection time: 0.443608045578 >> start... 13000 limit:1000 >> selection time: 0.49751496315 >> start... 14000 limit:1000 >> selection time: 12.0050361156 >> start... 15000 limit:1000 >> selection time: 26.3596658707 >> >> start... 16000 limit:1000 >> selection time: 43.5269529819 -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
