postgres-xc-general Mailing List for Postgres-XC

Could you check the log of the coordinator you connected?   This may tell
something about the issue.

Also, could you check if all the nodes (gtm, coordinators and datanodes)
are working correctly?   You can do it with psql like:

psql -p port -h host -c 'select 1'

where port and host is these of each node you're testing.  If there're
anything wrong, psql will report an error.

Regards;
---
Koichi Suzuki



2013/8/9 <pos...@gz...>

>  We have a server with 64 cores and 384GB of RAM.  We'd like to take
> advantage of that hardware to speed up some queries that take 8+ hours to
> run, and Postgres-XC seems like a good fit.
>
> I've setup a cluster of 8 data nodes (I'll increase that to 48 for real
> usage), 1 coordinator, and 1 GTM, all running on the same physical server.
> I'm using 1.1 beta, on Postgres 9.2.
>
> Here are the relevant commands (near-identical repeated commands are
> omitted):
> /usr/local/pgsql/bin/initdb -D /var/lib/pgsql/9.2/postgres-xc/data_coord1
> --nodename coord1
> /usr/local/pgsql/bin/initdb -D
> /var/lib/pgsql/9.2/postgres-xc/data_datanode1 --nodename datanode1
> ...
> /usr/local/pgsql/bin/initdb -D
> /var/lib/pgsql/9.2/postgres-xc/data_datanode8 --nodename datanode8
> /usr/local/pgsql/bin/initgtm -D /var/lib/pgsql/9.2/postgres-xc/data_gtm -Z
> gtm
> /usr/local/pgsql/bin/gtm -D /var/lib/pgsql/9.2/postgres-xc/data_gtm >>
> /var/lib/pgsql/9.2/postgres-xc/logfile 2>&1 &
> /usr/local/pgsql/bin/postgres -X -p 15432 -D
> /var/lib/pgsql/9.2/postgres-xc/data_datanode1 >>
> /var/lib/pgsql/9.2/postgres-xc/logfile 2>&1 &
> ...
> /usr/local/pgsql/bin/postgres -X -p 15439 -D
> /var/lib/pgsql/9.2/postgres-xc/data_datanode8 >>
> /var/lib/pgsql/9.2/postgres-xc/logfile 2>&1 &
> /usr/local/pgsql/bin/postgres -C -p 5477 -D
> /var/lib/pgsql/9.2/postgres-xc/data_coord1 >>
> /var/lib/pgsql/9.2/postgres-xc/logfile 2>&1 &
> /usr/local/pgsql/bin/psql -p 5477 -c "CREATE NODE datanode1 WITH (TYPE =
> 'datanode', PORT = 15432)" postgres
> ...
> /usr/local/pgsql/bin/psql -p 5477 -c "CREATE NODE datanode8 WITH (TYPE =
> 'datanode', PORT = 15439)" postgres
> /usr/local/pgsql/bin/psql -p 5477 -c "SELECT pgxc_pool_reload()" postgres
> /usr/local/pgsql/bin/createdb -p 5477 test
> /usr/local/pgsql/bin/psql -p 5477 test
>
> I then created the following tables:
> CREATE TABLE trails1 (
>     id text,
>     a_lat double precision,
>     a_long double precision,
>     b_lat double precision,
>     b_long double precision,
>     trail_id character varying(20),
>     type character varying(4),
>     distance numeric(10,5)
> );
> CREATE INDEX table1_a_lat ON table1 USING btree (a_lat);
> CREATE INDEX table1_a_long ON table1 USING btree (a_long);
> CREATE INDEX table1_b_lat ON table1 USING btree (b_lat);
> CREATE INDEX table1_b_long ON table1 USING btree (b_long);
> CREATE INDEX table1_type ON table1 USING btree (type);
> CREATE INDEX table1_distance ON table1 USING btree (distance);
>
> CREATE TABLE trails2 (
>     a_lat double precision,
>     a_long double precision,
>     b_lat double precision,
>     b_long double precision,
>     type character varying(5),
>     distance numeric(16,8)
> );
> CREATE INDEX table2_a_lat ON table2 USING btree (a_lat);
> CREATE INDEX table2_a_long ON table2 USING btree (a_long);
> CREATE INDEX table2_b_lat ON table2 USING btree (b_lat);
> CREATE INDEX table2_b_long ON table2 USING btree (b_long);
> CREATE INDEX table2_type ON table2 USING btree (type);
> CREATE INDEX table2_distance ON table2 USING btree (distance);
>
> I think I should have had something in the table definition about how to
> partition the data.
>
> I populated them using copy, with 331,106 rows in table1, and 1,124,421
> rows in table2.
>
> Simple queries return the right values:
>
> select count(*) as count from table1;
> 331106
>
> select count(*) as count from table2;
> 1124421
>
> When I do a big query (the one that normally takes hours to complete) it
> is only using one CPU core.  I expected to see Postgres processes using
> near 100% CPU on 8 cores.
>
> SELECT
>     count(*) as count
> FROM
>     trails1
> WHERE
>     not exists (
>         SELECT
>             'x'
>         FROM
>             trails2
>         WHERE
>             trails2.a_lat >= trails1.a_lat - 0.000833 AND
>             trails2.a_lat <= trails1.a_lat + 0.000833 AND
>             trails2.a_long >= trails1.a_long - 0.000833 AND
>             trails2.a_long <= trails1.a_long + 0.000833 AND
>             trails2.b_lat >= trails1.b_lat - 0.000833 AND
>             trails2.b_lat <= trails1.b_lat + 0.000833 AND
>             trails2.b_long >= trails1.b_long - 0.000833 AND
>             trails2.b_long <= trails1.b_long + 0.000833 AND
>             (
>                 trails2.type = trails1.type OR
>                 trails2.type = 'S'
>             ) AND
>             trails2.distance >= trails1.distance - 1.0 AND
>             trails2.distance <= trails1.distance + 1.0
>         );
>
> I haven't let it run to completion.  After seeing the lack of CPU usage I
> went looking for other problems (and found them).
>
> If I reload the pool and then check it, I get true:
> SELECT pgxc_pool_reload();
> t
>
> SELECT pgxc_pool_check();
> t
>
> But after I interact with the data at all, it fails:
> select count(*) as count from table1;
> 331106
>
> SELECT pgxc_pool_check();
> f
>
> So I don't think it's working properly.  The logs don't show anything.
>
> Any suggestions?
>
> Thanks!
>
>
>
>
>
>
>
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