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Callidon / sparql-engine

🚂 A framework for building SPARQL query engines in Javascript/Typescript
https://callidon.github.io/sparql-engine
MIT License
99 stars 14 forks source link

BGP question #4

Closed dwhitney closed 5 years ago

dwhitney commented 6 years ago

This is not really an issue but more of a question - some of the data sets I'm working with have time series data in them and basic queries to get date and value are suffering from the N + 1 select problem - date and value are related to an entity with a blank node, so I get a date and time query for each blank node which can be in the thousands. It's slow and I'm wondering if you have some suggestions for improving performance. My naive guess is that something different than the indexed nested loop join would be better but I'm new to this stuff and could use a pointer in the right direction

Callidon commented 6 years ago

I'm struggling to understand your issue. Do you have an example with a SPARQL query and some data to illustrate the issue?

dwhitney commented 6 years ago

I probably can't put anything together until Monday, but I think a sorted merge join will solve my issue especially since the datasets are in sorted order. I will post more if my experiments are successful

On Sat, Sep 29, 2018, 1:08 PM Thomas Minier notifications@github.com wrote:

I'm struggling to understand your issue. Do you have an example with a SPARQL query and some data to illustrate the issue?

— You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub https://github.com/Callidon/sparql-engine/issues/4#issuecomment-425660445, or mute the thread https://github.com/notifications/unsubscribe-auth/AACCoTykbs02mW4d1T41XIzkmipF9taqks5uf6kFgaJpZM4XAjlK .

Callidon commented 6 years ago

Ok, no problem to wait until Monday, it's the week-end after all ;) Concerning which join algorithms to use, I will wait for your example before drawing any conclusion.