Assuming you were able to create this database, it might by a good idea to trim down
the problem by growing the database in a few steps to isolate if size is the problem.

Are there any known limits of tables sizes? Row-wise or size-wise?

There are no limits, except for your diskspace.

The last resort is to attach a debugger to the server before you issue the query to catch
a stack trace where it happens in the code base.

Do you have any how-to doc for that?

roughly:
1) start mserver5 using the latest arguments line you can find in the merovingian.log file
2) in a separate window locate the process id of that mserver5 instance
3) attach the debugger:
  gdb mserver5 <processId>
  continue

4) use mclient to connect to the server and run the query
If it segfaults you can see it in the window 2)
issue a backtrace/bt/where command to find the stack trace.

regards, Martin

Thank you for your help,

Nikita

regards, Martin


On 06/06/16 18:13, Nikita Salnikov-Tarnovski wrote:

Hello. I am evaluating MonetDB to use in our project, but so far have some real problems with MonetDB constantly having segmentation faults. Here is my setup:

I am using AWS EC2 instance with 16GB of RAM, monetdb farm is location on ESB volume.

Welcome to mclient, the MonetDB/SQL interactive terminal (Jul2015-SP4)
Database: MonetDB v11.21.19 (Jul2015-SP4), 'mapi:monetdb://ip-10-0-0-47:50000/mysql-copy'

In there I have several tables, among them is one table I am most interested in, problemsview, with total columnsize of 120GB, largest column is around 11GB.

The moment I execute “select count(1) from problemsview;” I get segmentation fault:

mserver5[1300]: segfault at 0 ip 00007f86a0ca0712 sp 00007f869b6faa80 error 4 in lib_sql.so[7f86a0c72000+199000]

Next
select * from problemsview limit 10;

wait for 20-30 seconds, and then segmentation fault:
mserver5[1313]: segfault at 18 ip 00007f68cf2a0726 sp 00007f68ce14ea80 error 4 in lib_sql.so[7f68cf272000+199000]

So essentially I cannot do anything, I always get segmentation fault. Can this be fixed somehow?

Thank you in advance,

Nikita Salnikov-Tarnovski
Plumbr Founder and Master Developer
@JavaPlumbr/@iNikem



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