This is not a bug. Each query requires a round-trip to the server so it is natural that a lot of queries take additional time.
/M On Wed, Jul 29, 2009 at 1:01 PM, Axel Fix<axel....@sitqsystems.com> wrote: > > The following bug has been logged online: > > Bug reference: 4954 > Logged by: Axel Fix > Email address: axel....@sitqsystems.com > PostgreSQL version: 8.3 and 8.4 > Operating system: Windows XP > Description: very slow query with 2 statements > Details: > > Hello, > > I have a simple er-model with 3 tables for 2D objects and use the following > statements for query data: > s1 = "select t1.id,t1.type... from t0,t1 > where t1.id_t0 = t0.id and t0.name='x1000'" > s2 = "select X,Y from t2 where id_t1=?" > > The table t1 returns 1000 elements which I iterate and use the returned id > for the prepared statement s2. This way the server executes s2 1000 times. > This seems to be very slow (>10sec!!! - the time grows with the whole number > of datasets in the tables). > > Table t2 contains about 2.500 elements for the 1000 elements of t1. > > If I use a single statement, where I get an all in one result set, it will > be finished after <100ms! > The collected statement (with right table and column names) is: > sc = "select t_graphobj.ID,type,fill,color,x,y\n" + > " from t_graphdata,t_graphobj,t_names\n" + > " where ID_GRAPHOBJ=t_graphobj.ID\n" + > " and t_graphobj.ID_NAMES=t_names.ID\n" + > " and t_names.NAME='x1000'\n" + > " order by t_graphobj.id" > > If you need the java source code and SQL statements for the table, let me > know. > > Thanks in advance, > > Axel Fix > > -- > Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-bugs > -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs
