[MonetDB-users] Select Query crashes the server with "--single-user" option
Hi,
I am trying to use MonetDB in single user mode. While I could load the data using "COPY INTO" command and run a few select queries successfully, the moment i run a query with group by on more than one column, the server crashes saying " ---- >Segmentation fault". Is there a way to get around it? or, am I using it the wrong way? I could recreate the problem doing this--- 1. Start server with "sudo mserver5 --dbfarm='/home/user/work/tmp/data/test' --single-user" 2. start mclient (and create a simple table and fire a select query with group by on multiple columns)
create table test ( market_size int not null, market int not null, state
int not null);
select count(*) from test group by market_size, state;
-- server crashes on the above query.
I am using MonetDB 5 server v11.3.3 "Apr2011-SP1" (64-bit, 64-bit oids)
Thanks, Ram
Hi Ramak,
I can reproduce your problem.
Could you please file a bug report via http://bugs.monetdb.org/ ?
Until we manage to locate and hopefully fix the problem, I'd recommend to simply omit the "--single-user" option --- everything seems to work fine without "--single-user".
What was/is your reason/need to use MonetDB in single-user mode?
Stefan
On Sun, Jun 12, 2011 at 09:59:37AM -0700, Ramak wrote:
Hi,
I am trying to use MonetDB in single user mode. While I could load the data using "COPY INTO" command and run a few select queries successfully, the moment i run a query with group by on more than one column, the server crashes saying " ---- >Segmentation fault". Is there a way to get around it? or, am I using it the wrong way? I could recreate the problem doing this---
- Start server with "sudo mserver5 --dbfarm='/home/user/work/tmp/data/test'
--single-user" 2. start mclient (and create a simple table and fire a select query with group by on multiple columns)
create table test ( market_size int not null, market int not null, state
int not null);
select count(*) from test group by market_size, state;
-- server crashes on the above query.
I am using MonetDB 5 server v11.3.3 "Apr2011-SP1" (64-bit, 64-bit oids)
Thanks, Ram
-- View this message in context: http://old.nabble.com/Select-Query-crashes-the-server-with-%22--single-user%... Sent from the monetdb-users mailing list archive at Nabble.com.
EditLive Enterprise is the world's most technically advanced content authoring tool. Experience the power of Track Changes, Inline Image Editing and ensure content is compliant with Accessibility Checking. http://p.sf.net/sfu/ephox-dev2dev _______________________________________________ MonetDB-users mailing list MonetDB-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/monetdb-users
Thanks Stefan. I have filed a bug report.
The Application iam working on would always have a single user and the data is never modified after initial load (though lots of select queries are run after initial load). Trying to configure monetDB to suit the scenario; i am thinking "--readonly" and "--single-user" options could avoid transactional overheads and concurrency (locking etc) overheads and give a better querying performace. Right now, i am only testing the concept to see if this gives better performace. Please do suggest if anything else can give us better quering results on monetDB.
Stefan Manegold wrote:
Hi Ramak,
I can reproduce your problem.
Could you please file a bug report via http://bugs.monetdb.org/ ?
Until we manage to locate and hopefully fix the problem, I'd recommend to simply omit the "--single-user" option --- everything seems to work fine without "--single-user".
What was/is your reason/need to use MonetDB in single-user mode?
Stefan
On Sun, Jun 12, 2011 at 09:59:37AM -0700, Ramak wrote:
Hi,
I am trying to use MonetDB in single user mode. While I could load the data using "COPY INTO" command and run a few select queries successfully, the moment i run a query with group by on more than one column, the server crashes saying " ---- >Segmentation fault". Is there a way to get around it? or, am I using it the wrong way? I could recreate the problem doing this---
- Start server with "sudo mserver5
--dbfarm='/home/user/work/tmp/data/test' --single-user" 2. start mclient (and create a simple table and fire a select query with group by on multiple columns)
create table test ( market_size int not null, market int not null,
state int not null);
select count(*) from test group by market_size, state;
-- server crashes on the above query.
I am using MonetDB 5 server v11.3.3 "Apr2011-SP1" (64-bit, 64-bit oids)
Thanks, Ram
-- View this message in context: http://old.nabble.com/Select-Query-crashes-the-server-with-%22--single-user%... Sent from the monetdb-users mailing list archive at Nabble.com.
EditLive Enterprise is the world's most technically advanced content authoring tool. Experience the power of Track Changes, Inline Image Editing and ensure content is compliant with Accessibility Checking. http://p.sf.net/sfu/ephox-dev2dev _______________________________________________ MonetDB-users mailing list MonetDB-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/monetdb-users
-- | Stefan.Manegold @ CWI.nl | DB Architectures (INS1) | | http://CWI.nl/~manegold/ | Science Park 123 (L321) | | Tel.: +31 (0)20 592-4212 | 1098 XG Amsterdam (NL) |
EditLive Enterprise is the world's most technically advanced content authoring tool. Experience the power of Track Changes, Inline Image Editing and ensure content is compliant with Accessibility Checking. http://p.sf.net/sfu/ephox-dev2dev _______________________________________________ MonetDB-users mailing list MonetDB-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/monetdb-users
Ramak,
given that MonetDB uses an optimistic concurrency controle protocol rather than locking, single-user mode should not make any difference wrt. performance.
Running the server in --readonly mode (after the initial data loading) might give a slight performance advantage; but in general, I don't expect any significant differences here, either.
In general, MonetDB is designed to be "nob-less", hence, there should not be any need (in fact there are not many options) to tune the system.
Please let us know, in case you experience unexpected (slow) performance of MonetDB, and if so, in what kind of scenarios (data volume, data base schema, query workload, hardware, operating system, etc.).
Stefan
On Sun, Jun 12, 2011 at 11:04:13PM -0700, Ramak wrote:
Thanks Stefan. I have filed a bug report.
The Application iam working on would always have a single user and the data is never modified after initial load (though lots of select queries are run after initial load). Trying to configure monetDB to suit the scenario; i am thinking "--readonly" and "--single-user" options could avoid transactional overheads and concurrency (locking etc) overheads and give a better querying performace. Right now, i am only testing the concept to see if this gives better performace. Please do suggest if anything else can give us better quering results on monetDB.
Stefan Manegold wrote:
Hi Ramak,
I can reproduce your problem.
Could you please file a bug report via http://bugs.monetdb.org/ ?
Until we manage to locate and hopefully fix the problem, I'd recommend to simply omit the "--single-user" option --- everything seems to work fine without "--single-user".
What was/is your reason/need to use MonetDB in single-user mode?
Stefan
On Sun, Jun 12, 2011 at 09:59:37AM -0700, Ramak wrote:
Hi,
I am trying to use MonetDB in single user mode. While I could load the data using "COPY INTO" command and run a few select queries successfully, the moment i run a query with group by on more than one column, the server crashes saying " ---- >Segmentation fault". Is there a way to get around it? or, am I using it the wrong way? I could recreate the problem doing this---
- Start server with "sudo mserver5
--dbfarm='/home/user/work/tmp/data/test' --single-user" 2. start mclient (and create a simple table and fire a select query with group by on multiple columns)
create table test ( market_size int not null, market int not null,
state int not null);
select count(*) from test group by market_size, state;
-- server crashes on the above query.
I am using MonetDB 5 server v11.3.3 "Apr2011-SP1" (64-bit, 64-bit oids)
Thanks, Ram
-- View this message in context: http://old.nabble.com/Select-Query-crashes-the-server-with-%22--single-user%... Sent from the monetdb-users mailing list archive at Nabble.com.
EditLive Enterprise is the world's most technically advanced content authoring tool. Experience the power of Track Changes, Inline Image Editing and ensure content is compliant with Accessibility Checking. http://p.sf.net/sfu/ephox-dev2dev _______________________________________________ MonetDB-users mailing list MonetDB-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/monetdb-users
-- | Stefan.Manegold @ CWI.nl | DB Architectures (INS1) | | http://CWI.nl/~manegold/ | Science Park 123 (L321) | | Tel.: +31 (0)20 592-4212 | 1098 XG Amsterdam (NL) |
EditLive Enterprise is the world's most technically advanced content authoring tool. Experience the power of Track Changes, Inline Image Editing and ensure content is compliant with Accessibility Checking. http://p.sf.net/sfu/ephox-dev2dev _______________________________________________ MonetDB-users mailing list MonetDB-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/monetdb-users
-- View this message in context: http://old.nabble.com/Select-Query-crashes-the-server-with-%22--single-user%... Sent from the monetdb-users mailing list archive at Nabble.com.
EditLive Enterprise is the world's most technically advanced content authoring tool. Experience the power of Track Changes, Inline Image Editing and ensure content is compliant with Accessibility Checking. http://p.sf.net/sfu/ephox-dev2dev _______________________________________________ MonetDB-users mailing list MonetDB-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/monetdb-users
participants (2)
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Ramak -
Stefan Manegold