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---+ How can I get full <code>explain</code> and <code>profile</code> plans for a simple SPARQL query?
Starting with Virtuoso Commercial Release 6.4, and Virtuoso Open Source 6.1.5, <code>isql</code> offers 2 new modes for analyzing SPARQL queries:
1 Translate a SPARQL query into the correspondent SQL:
<verbatim>
SQL> SET SPARQL_TRANSLATE ON;
SQL> SELECT * FROM <graph> WHERE {?S a ?O};
---> Or execute query of your choice
SQL> SET SPARQL_TRANSLATE OFF;
</verbatim>
1 Generate compilation plan of an SQL query:
<verbatim>
SQL> SET EXPLAIN ON;
SQL> SELECT * FROM TABLE WHERE field = 'text';
---> Or execute query of your choice
SQL> SET EXPLAIN OFF;
</verbatim>
* The equivalent is <code>[[http://docs.openlinksw.com/virtuoso/fn_explain/][EXPLAIN()]]</code>, which is much more difficult to use; you cannot just copy-and-paste a query, as all quotes must be doubled within the <code>EXPLAIN(' ... ')</code>, as shown below:
<verbatim>
SQL> explain('select * from table where field = ''text''');
</verbatim>
1 Generate compilation and execution plan of an SQL query:
<verbatim>
SQL> SET PROFILE ON;
SQL> SELECT * FROM TABLE WHERE field = 'text';
---> Or execute query of your choice
SQL> SET PROFILE OFF;
</verbatim>
* The equivalent (available in Virtuoso 7 and later) is <code>[[http://docs.openlinksw.com/virtuoso/fn_profile/][PROFILE()]]</code>, which is much more difficult to use; you cannot just copy-and-paste a query, as all quotes must be doubled within the <code>PROFILE(' ... ')</code>, as shown below:
<verbatim>
SQL> profile('select * from table where field = ''text''');
</verbatim>
1 A more detailed query profile (compilation and execution) with cardinality can be obtained by executing the following following sequence
<verbatim>
SQL> __dbf_set('enable_qr_comment', 1);
SQL> __dbf_set('dbf_explain_level', 3);
SQL> SET PROFILE ON;
SQL> SET BLOBS ON;
SQL> SELECT * FROM TABLE WHERE field = 'text';
---> Or execute query of your choice
SQL> SET PROFILE OFF;
</verbatim>
Provide the generated plans for analysis.
---++ Example
Here is a simple example of how to combine the two options to get a full <code>explain()</code> plan for a simple SPARQL query:
1 Assume the following query:
<verbatim>
SELECT *
FROM <http://dbpedia.org>
WHERE
{
?s a ?o
}
LIMIT 10
</verbatim>
1. Use the <code>isql</code> command line tool to connect to your database, and execute:
<verbatim>
SQL> SET BLOBS ON;
-- in case output is very large
SQL> SET SPARQL_TRANSLATE ON;
SQL> SELECT * FROM <http://dbpedia.org> WHERE {?s a ?o} LIMIT 10;
SPARQL_TO_SQL_TEXT
VARCHAR
_______________________________________________________________________________
SELECT TOP 10 __id2i ( "s_1_0-t0"."S" ) AS "s",
__ro2sq ( "s_1_0-t0"."O" ) AS "o"
FROM DB.DBA.RDF_QUAD AS "s_1_0-t0"
WHERE "s_1_0-t0"."G" = __i2idn ( __bft( 'http://dbpedia.org' , 1))
AND "s_1_0-t0"."P" = __i2idn ( __bft( 'http://www.w3.org/1999/02/22-rdf-syntax-ns#type' , 1))
OPTION (QUIETCAST)
1 Rows. -- 1 msec.
SQL> SET SPARQL_TRANSLATE OFF;
</verbatim>
1. Use your mouse to select the query output, and paste it after the <code>SET EXPLAIN ON;</code>
command. Then hit the ENTER key.
<verbatim>
SQL> SET EXPLAIN ON;
SQL> SELECT TOP 10 __id2i ( "s_1_0-t0"."S" ) AS "s", __ro2sq ( "s_1_0-t0"."O" ) AS "o"
FROM DB.DBA.RDF_QUAD AS "s_1_0-t0"
WHERE "s_1_0-t0"."G" = __i2idn ( __bft( 'http://dbpedia.org' , 1))
AND "s_1_0-t0"."P" = __i2idn ( __bft( 'http://www.w3.org/1999/02/22-rdf-syn tax-ns#type' , 1))
OPTION (QUIETCAST)
;
REPORT
VARCHAR
_______________________________________________________________________________
{
from DB.DBA.RDF_QUAD by RDF_QUAD_POGS 4.5e+05 rows
Key RDF_QUAD_POGS ASC ($22 "s_1_0-t0.S", $21 "s_1_0-t0.O")
inlined <col=556 P = #type >
row specs: <col=554 G = #http://dbpedia.org >
After code:
0: $25 "s" := Call __id2i ($22 "s_1_0-t0.S")
5: $26 "o" := Call __ro2sq ($21 "s_1_0-t0.O")
10: BReturn 0
Select (TOP 10 ) ($25 "s", $26 "o", <$24 "<DB.DBA.RDF_QUAD s_1_0-t0>" spec 5>)
}
13 Rows. -- 1 msec.
SQL> SET EXPLAIN OFF;
</verbatim>
---++Related
* [[VirtTipsAndTricksGuide][Virtuoso Tips and Tricks Collection]]
* [[http://docs.openlinksw.com/virtuoso/rdfsparql.html][Virtuoso Documentation]]
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![[RDF Data]](/fct/images/sw-rdf-blue.png)
![[cxml]](/fct/images/cxml_doc.png)
![[csv]](/fct/images/csv_doc.png)
![[text]](/fct/images/ntriples_doc.png)
![[turtle]](/fct/images/n3turtle_doc.png)
![[ld+json]](/fct/images/jsonld_doc.png)
![[rdf+json]](/fct/images/json_doc.png)
![[rdf+xml]](/fct/images/xml_doc.png)
![[atom+xml]](/fct/images/atom_doc.png)
![[html]](/fct/images/html_doc.png)