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[Bigdata-developers] SPARQL DELETE, INSERT performance question
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From: Kevin F. <kf...@ar...> - 2016-08-17 19:20:56
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Dear All,
I have a question about SPARQL DELETE/INSERT performance.
We have a job that issues two DELETE queries followed by an INSERT
query, per request, to keep our triplestore up to date. The pattern is
as follows:
DELETE { <URI> ?p ?o };
DELETE { <URI/other> ?p ?o };
INSERT {
<URI> <new> '1' .
<URI> <new> '2' .
<URI> <new> '3' .
<URI/other> <new> '1' .
}
We've noted two things:
1) If a store is empty, this is relatively fast.
2) IF the store is configured for automatic inferencing, it is slower
than a store without that feature activated.
Neither of those observations seems particularly surprising, but each of
those two DELETE statements and the one INSERT takes more than 3 seconds
against a store with only 4.6 million triples. See below for a sample
of the output.
Blazegraph is allocated 4g of memory.
We're working within a framework that produces these series of queries
so, before making any custom modifications, I was wondering if this
performance is to be expected? If not, would it point to a configuation
issue of some kind, or something else?
Also, I've noted that issuing a DELETE HTTP request appears to handle
the deletes faster, but is there a more optimal way to construct those
three queries (the DELETE/INSERT WHERE pattern did not appear to improve
matters based on a few isolated tests).
Cordially,
Kevin
$ curl -X POST https://laketsidx/blazegraph/namespace/lakeidx/sparql
--data @bg-test-02.sparql -H "Content-type:
application/x-www-form-urlencoded"
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd"><html><head><meta
http-equiv="Content-Type"
content="text/html;charset=UTF-8"><title>blazegraph™ by
SYSTAP</title
></head
><body<p>totalElapsed=33ms, elapsed=33ms, connFlush=0ms,
batchResolve=0, whereClause=23ms, deleteClause=9ms, insertClause=23ms</p
><hr><p>totalElapsed=2579ms, elapsed=21ms, connFlush=2524ms,
batchResolve=0, whereClause=21ms, deleteClause=0ms, insertClause=21ms</p
><hr><p>totalElapsed=2582ms, elapsed=2ms, connFlush=0ms,
batchResolve=0, whereClause=0ms, deleteClause=0ms, insertClause=0ms</p
><hr><p>COMMIT: totalElapsed=3118ms, commitTime=1471453475719,
mutationCount=62</p
></html
$ curl -X POST https://laketsidx/blazegraph/namespace/lakeidx/sparql
--data @bg-test-02.sparql -H "Content-type:
application/x-www-form-urlencoded"
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd"><html><head><meta
http-equiv="Content-Type"
content="text/html;charset=UTF-8"><title>blazegraph™ by
SYSTAP</title
></head
><body<p>totalElapsed=24ms, elapsed=24ms, connFlush=0ms,
batchResolve=0, whereClause=12ms, deleteClause=11ms, insertClause=12ms</p
><hr><p>totalElapsed=2966ms, elapsed=12ms, connFlush=2929ms,
batchResolve=0, whereClause=12ms, deleteClause=0ms, insertClause=12ms</p
><hr><p>totalElapsed=2969ms, elapsed=2ms, connFlush=0ms,
batchResolve=0, whereClause=0ms, deleteClause=0ms, insertClause=0ms</p
><hr><p>COMMIT: totalElapsed=3669ms, commitTime=1471453483251,
mutationCount=62</p
></html
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