Hi Alexander, The error you're getting is indicative of a timeout -- a long-running query or a runaway memory usage.
Follow up questions and suggestions - 1. How are you running this query? via SPARQL endpoint or a built-in? 2. Are there any default inference setting on the database? (from your query I'd guess no, but that would affect the server a lot) If you're using a built-in to run the query, I'd try changing the "optimize" option, which may lead to a better query plan. I'd also suggest using 8.0-2 as there have been rapid improvements in speed a query processing throughout the dev cycles. If neither suggestion gets you anywhere, this is probably a query and dataset we'd want to take a closer look at... the query doesn't look like one I'd expect to have issues. Charles ________________________________ From: [email protected] [[email protected]] on behalf of Takacs [[email protected]] Sent: Wednesday, April 22, 2015 8:30 AM To: [email protected] Subject: [MarkLogic Dev General] SPARQL queries causing XDMP-MEMCANCELED Hi, We are performing a series of different SPARQL queries on a database containing ~5 million triples. Our queries often cause a XDMP-MEMCANCELED-error though not consistently, they mostly return a correct result within a few seconds or less. Some queries occationally seems to hang and cause the server to run at 100% CPU until the query times out. We have tried increasing what memory-related settings we could find. This query runs fine on other triple stores/engines. We are running MarkLogic 8.0-11 AWS instance with 8 gb of internal memory and 16 gb of swap space. Example of a query that sometimes causes the error: PREFIX xsd: <http://www.w3.org/2001/XMLSchema#> PREFIX t5_m: <http://url.com/T5/model#> PREFIX t5_d: <http://url.com/T5/data#> SELECT DISTINCT ?_app_id ( ?_err as ?_reason ) ?_comment ?_severity WHERE { BIND ( 3 as ?_severity) BIND ( "Generated by HL7 v2 Conformance Profile of IHE PCD-01 message" as ?_comment ) FILTER( ?_app_id = 'APP_ID') FILTER ( ?_ts >= '2015-04-21T09:04:07.871' ) FILTER ( ?_ts <= '2015-04-21T09:07:43.973' ) ?ACK t5_m:hasMSH ?MSH . ?MSH t5_m:hasMSH.5 ?MSH_5 . ?MSH_5 t5_m:hasHD.1 ?HD_1 . ?HD_1 t5_m:hD.1Value ?_app_id . ?ACK t5_m:hasMSA ?MSA . ?MSA t5_m:hasMSA.2 ?MSA_2 . ?MSA_2 t5_m:mSA.2Value ?_msg_id . ?PCD_01_Message a t5_m:PCD_01_Message . ?PCD_01_Message t5_m:id ?_msg_id . ?PCD_01_Message t5_m:timeStamp ?_ts . ?ACK t5_m:hasERR ?ERR . ?ERR t5_m:hasERR.7 ?ERR_7 . ?ERR_7 t5_m:eRR.7Value ?_err . } Is there something in the configuration that we are missing or does the query itself have issues? Thanks a lot for any suggestions! Yours truly, Alexander
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