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https://issues.apache.org/jira/browse/JENA-2228?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17466643#comment-17466643
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Andy Seaborne edited comment on JENA-2228 at 12/30/21, 9:14 AM:
----------------------------------------------------------------
The execution is on quads for a query directly to TDB.
{noformat}
OpExecutorTDB2.execute(OpQuadPattern, ...)
{noformat}
I suggest you walk through a query
{noformat}
SELECT * {
?x :p ?o .
?o :q ?z .
{noformat}
with data
{noformat}
:x :p :o .
:o :q :z .
{noformat}
which does not involve RDF-star. (that uses a different approach to avoid
needing database format on-disk changes).
Don't forget that ARQ is a streaming engine - work is done only when the
results are consumed walking the iterator for a ResultSet.
The base level access is in {{{}StageMatchTuple{}}}.
Access to the node tuple table is:
{noformat}
Iterator<Tuple<NodeId>> iterMatches =
nodeTupleTable.find(TupleFactory.create(ids));
{noformat}
was (Author: andy.seaborne):
The execution is on quads for a query directly to TDB.
{noformat}
OpExecutorTDB2.execute(OpQuadPattern, ...)
{noformat}
I suggest you walk though a query
{noformat}
SELECT * {
?x :p ?o .
?o :q ?z .
{noformat}
with data
{noformat}
:x :p :o .
:o :q :z .
{noformat}
which does not involve RDF-star. (that uses a different approach to avoid
needing datbase format on-disk changes).
The base level access is in {{StageMatchTuple}}.
Access to the node tuple table is:
{noformat}
Iterator<Tuple<NodeId>> iterMatches =
nodeTupleTable.find(TupleFactory.create(ids));
{noformat}
> Does Fuseki2 use TDB indexes or indexes for in-memory store?
> ------------------------------------------------------------
>
> Key: JENA-2228
> URL: https://issues.apache.org/jira/browse/JENA-2228
> Project: Apache Jena
> Issue Type: Question
> Components: Fuseki, TDB
> Affects Versions: Jena 3.17.0
> Environment: I am running the jena-fuseki-server-3.17.0.jar file from
> jena-fuseki2/jena-fuseki-server/target/ as follows
> {code:java}
> java -Xmx500g -jar fuseki-jenaclone.jar --tdb2 --loc=db/jena
> --timeout=1000000 /jena &{code}
> Reporter: Martin Pekár
> Priority: Major
>
> Based on logging messages inserted into various places in the indexes in the
> TDB module (NodeTupleTableConcrete, TupleIndexBase, NodeTableNative,
> BPlusTree), I can see that the B+ tree is only used once per query. I have
> inserted logging messages for every finding method to see which classes are
> used when querying. I would expect to the the B+ tree be used several times
> per query.
>
> I use the error logging level, and I inserted logging in the class
> constructors to make sure logging worked. I see construction of all the index
> classes.
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