Re: [Virtuoso-users] estimating NumberOfBuffers

2015-04-22 Thread Hugh Williams
Hi Andy, The amount of memory and hence NumberOfBuffers a dataset requires for being hosted/cached in memory for best performance varies depending on how well a given dataset can be compressed, which varies based on its structure (data regularity) and size of literals etc. and thus makes this h

[Virtuoso-users] Preview SPARQL query performance

2015-04-22 Thread Fernando GuimarĂ£es Ferreira
Can you think a way of trying to preview whether a query will return a huge load of results? I am trying to avoid timeout server errors. As example a query like: SELECT DISTINCT COUNT(?entity) WHERE { VALUES ?entity_type { dbpedia-owl:Person

[Virtuoso-users] estimating NumberOfBuffers

2015-04-22 Thread Andy Jenkinson
Hi, I would like to find a more efficient way to work out how much memory to allocate to some new Virtuoso VMs, which is directly dependent on how many buffers I allocate to Virtuoso. I want to allocate enough memory so that the column store is effectively operating in-memory. To work this out,

Re: [Virtuoso-users] check if a stored procedure exists

2015-04-22 Thread Gang Fu
It may look verbose, but here it is: create procedure drop_procedure_if_exist (in pname varchar) { declare stmt varchar; declare mdta_out any; declare res_vec_out, param_vec any; declare sql_state, err_msg varchar; declare num_cols_out integer; stmt := 'SELECT * from SYS_PROCEDURES w