I've been working extensively with Wikidata for about a year now and have installed a local Wikidata instance a handful of times as per the directions found in the official mediaWiki article on Wikidata. I decided to install an instance afresh just recently and have encountered a puzzling problem. After running the loadRestAPI.sh command, the wikidata.jnl database was about 560G which is big but not as big as I expected it to be so I tried to query the database using a Python script and the SPARQLWrapper package but no query returned any results. Even the following query returned no results:
SELECT ?item WHERE {
?item ?prop ?val.
} LIMIT 1
There were no errors, so the connection to the database was created, but still no results. If I change the name of the endpoint variable in my python script to a different host at my lab that is running an outdated Wikidata service, the query returns results. Clearly the issue is with this new, potentially incomplete instance.
How could my wikidata.jnl file contain 560G worth of data but not contain a single RDF-triple? This has never happened before to me.
