Hi all,
I suspect this problem/bug has been dealt with already, but I couldn't
find anything in the mail archives.
I'm using postgres 7.3, and I managed to recreate the problem using the
attached
files.
The database structure is in slow_structure.sql
After creating the database, using this script, I ran run_before_load__fast.sql
Then I created a load file using create_loadfile.sh (It creates a file called
load.sql)
I timed the loading of this file, and it loaded in 1 min 11.567 sec
Then I recreated the database from slow_structure.sql, ran
run_before_load__slow.sql,
and then loaded the same load.sql and it took 3 min 51.293 sec which is about 6
times slower.
I tried the same thing on postgres 8.0.0 to see if it does the same thing, but
there it
was consistently slow : 3 min 31.367 sec
The only way I got the load.sql to load fast on postgres 8.0.0, was by not
creating
any of the foreign key constraints that point to the "main" table, and then
enabling them
afterwards. This gave me the fastest time overall : 1 min 4.911 sec
My problem is that on the postgres 7.3.4 database I'm working with, a load
process that
used to take 40 minutes, now takes 4 hours, because of 3 rows data being loaded
into
a table (similar in setup to the "main" table in the example) before the
indexes were created.
(This happens automatically when you dump and re-import the database (7.3.4))
Is there a way to get it to load fast again on the 7.3 database without
dropping the foreign
key constraints (After running run_before_load_slow.sql) ?
And, if someone knows off-hand, what's happening here?
TIA
Kind Regards
Stefan#!/bin/bash
for x in one two three four five six seven eight nine ten
do
for y in eleven twelve thirteen fourteen fifteen sixteen seventeen eighteen nineteen twenty
do
for z in `seq 1 100`
do
echo "insert into main (c_text,d_text) values ('${x}','${y}');" >> load.sql
echo "insert into a(id) values (currval('public.main_id_seq'::text));" >> load.sql
echo "insert into b(id) values (currval('public.main_id_seq'::text));" >> load.sql
echo "insert into e(id) values (currval('public.main_id_seq'::text));" >> load.sql
echo "insert into f(id) values (currval('public.main_id_seq'::text));" >> load.sql
echo "insert into g(id) values (currval('public.main_id_seq'::text));" >> load.sql
echo "insert into h(id) values (currval('public.main_id_seq'::text));" >> load.sql
done
done
done
run_before_load__fast.sql
Description: Binary data
run_before_load__slow.sql
Description: Binary data
slow_structure.sql
Description: Binary data
---(end of broadcast)---
TIP 9: the planner will ignore your desire to choose an index scan if your
joining column's datatypes do not match
