Hi
Each MAL instruction is executed by a single thread. Some operators require the complete input to be available, such as in your case the group.subgroup().
martin
On 18/01/15 01:27, shamsul hassan wrote:
Hi All,
I have recently install monetdb "OCT 2014-SP1" release on my Oracle Enterprise 6 Linux server.
Server configuration -
8 CPU Cores 64 GB RAM
I have loaded a data set with 70 columns having 15 Millions Rows.
I have started mserver5 as below --
mserver5 --debug=10 --set *gdk_nr_threads=8* --dbpath=/data/monetdb/testdb --set mapi_open=true --set mapi_port=54321 --set merovingian_uri=mapi:monetdb://localhost:54321/testdb --set mapi_usock=/data/monetdb/testdb/.mapi.sock --set monet_vault_key=/data/monetdb/testdb/.vaultkey --set sql_optimizer=default_pipe --set max_clients=64
Now I have ran a query as below --
select product_type,COUNT(DISTINCT sales_document),sum(ord_qty) FROM bookings where ord_entry_date between '2014-04-01' and '2014-10-01' group by product_type;
This query took around 90 Secs .. So I started tomograph and checked plotted graph ... which shows the parallelism usage as 39.9 % only and its utilizing only 1 thread with maximum time went in the step - group.subgroupdone almost 98%.
My Question is that even I have started the server with gdk_nr_threads=8 , then why it is just using single thread.
More info --
mserver5 --version
MonetDB 5 server v11.19.7 "Oct2014-SP1" (64-bit, 64-bit oids)
Copyright (c) 1993-July 2008 CWI
Copyright (c) August 2008-2014 MonetDB B.V., all rights reserved
Visit http://www.monetdb.org/ for further information
Found 63.0GiB available memory, 8 available cpu cores
Libraries:
libpcre: 7.8 2008-09-05 (compiled with 7.8)
openssl: OpenSSL 1.0.1e 11 Feb 2013 (compiled with OpenSSL 1.0.1e-fips 11 Feb 2013)
libxml2: 2.7.6 (compiled with 2.7.6)
Compiled by: root@localhost (x86_64-unknown-linux-gnu)
Compilation: gcc -O3 -fomit-frame-pointer -pipe -D_FORTIFY_SOURCE=2
Linking : /usr/bin/ld -m elf_x86_64
Any pointers ??
Thanks
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