5 Replies Latest reply on Jun 7, 2013 5:54 PM by alwu-Oracle

    SPARQL Update with Jena Adapter

    martani
    martani May 31, 2013 5:01 PM
      Hi,

      I am using the following SPARQL Update query: 
      DELETE { ?s ?p ?o }
WHERE {
    ?s  :isUpdatedQRY  "no".
    ?s  ?p  ?o .
}
      However, when I run it (with debug messages enabled), I notice that some operations are taking too long to run: 
      <<[DEBUG 18:48:28] [OracleTranslator:202] [main] >> encode: hit a plain literal, val = no
<<[DEBUG 18:48:38] [OracleTranslator:202] [main] >> encode: hit a plain literal, val = Graph4
<<[DEBUG 18:49:05] [OracleTranslator:202] [main] >> encode: hit a plain literal, val = no
<<[DEBUG 18:49:14] [OracleTranslator:202] [main] >> encode: hit a plain literal, val = Graph3
      As you can see, it takes between 9 seconds to 17 seconds for the next operation to execute.
      Do you have any idea what might be causing this?

      Regards.
        • 1. Re: SPARQL Update with Jena Adapter
          alwu-Oracle
          alwu-Oracle Jun 2, 2013 11:10 PM (in response to martani)
          Hi,

          Could you please cut & paste here the execution plan (from EM)?

          Thanks,

          Zhe Wu
          • 2. Re: SPARQL Update with Jena Adapter
            martani
            martani Jun 4, 2013 2:28 PM (in response to alwu-Oracle)
            Hi,

            I notice this SQL query executed: 
            DELETE    /*+ index(app MODEL_A_IDX) */
FROM  MY_SCHEMA.MODEL_TAB_A APP
WHERE BITAND (APP."TRIPLE".RDF_M_ID, 79228162514264337593543950335 - 4294967295) / 4294967296 = 
        (CASE
             WHEN INSTR (:B1, 'g') = 0
             THEN 0
             ELSE SYS_OP_RAWTONUM ( SUBSTR (:B1, INSTR (:B1, 'g') + 1, INSTR (:B1, '_') - INSTR (:B1, 'g') - 1))
          END)
     AND (APP."TRIPLE".RDF_S_ID) = 
               SYS_OP_RAWTONUM (SUBSTR (:B1, INSTR (:B1, '_') + 1, INSTR (:B1, '_', INSTR (:B1, '_') + 1) - INSTR (:B1, '_') - 1))
     AND (APP."TRIPLE".RDF_P_ID) = 
               SYS_OP_RAWTONUM (SUBSTR (:B1, INSTR (:B1, '_', 1, 2) + 1, INSTR (:B1, '_', 1, 3) - INSTR (:B1, '_', 1, 2) - 1))
     AND (APP."TRIPLE".RDF_C_ID) =
               SYS_OP_RAWTONUM (SUBSTR (:B1, INSTR (:B1, '_', 1, 3) + 1, LENGTH (:B1) - INSTR (:B1, '_', 1, 3)))
            And this is the execution plan: 
            PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------
| Id  | Operation          | Name      | Rows  | Bytes | Cost (%CPU)| Time     |
--------------------------------------------------------------------------------
|   0 | DELETE STATEMENT   |           |     1 |    59 | 10915  (15)| 00:02:11 |
|   1 |  DELETE            | NDB_TPL_A |       |       |            |          |
|*  2 |   TABLE ACCESS FULL| NDB_TPL_A |     1 |    59 | 10915  (15)| 00:02:11 |
--------------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

   2 - filter("APP"."SYS_NC00003$"=SYS_OP_RAWTONUM(HEXTORAW(SUBSTR(:B1,I
              NSTR(:B1,'_',1,3)+1,LENGTH(:B1)-INSTR(:B1,'_',1,3)))) AND
              "APP"."SYS_NC00006$"=SYS_OP_RAWTONUM(HEXTORAW(SUBSTR(:B1,INSTR(:B1,'_',1
              ,2)+1,INSTR(:B1,'_',1,3)-INSTR(:B1,'_',1,2)-1))) AND
              "APP"."SYS_NC00005$"=SYS_OP_RAWTONUM(HEXTORAW(SUBSTR(:B1,INSTR(:B1,'_')+
              1,INSTR(:B1,'_',INSTR(:B1,'_')+1)-INSTR(:B1,'_')-1))) AND
              BITAND("APP"."SYS_NC00004$",79228162514264337589248983040)/4294967296=CA
              SE INSTR(:B1,'g') WHEN 0 THEN 0 ELSE

PLAN_TABLE_OUTPUT
-----------------------------------------------------------------------------------------------
              SYS_OP_RAWTONUM(HEXTORAW(SUBSTR(:B1,INSTR(:B1,'g')+1,INSTR(:B1,'_')-INSTR(:B1,'g')-1))) END )
            Notice that we do not have a MODEL_A_IDX index; is this created automatically after a call to SEM_APIS.CREATE_SEM_MODEL?

            Thanks.
            • 3. Re: SPARQL Update with Jena Adapter
              alwu-Oracle
              alwu-Oracle Jun 5, 2013 11:38 PM (in response to martani)
              Hi,

              You can invoke the rebuildApplicationTableIndex() method against a GraphOracleSem object.
              It will re-recreate the index that is critical to delete performance.

              Thanks,

              Zhe Wu
              • 4. Re: SPARQL Update with Jena Adapter
                martani
                martani Jun 7, 2013 5:11 PM (in response to alwu-Oracle)
                Hi,

                Thank you very much for the reply, it works indeed. I can see the index range scan in the execution plan now: 
                DELETE STATEMENT, GOAL = ALL_ROWS
 DELETE                              USER    MODEL_A               
  TABLE ACCESS BY INDEX ROWID               USER    MODEL_A
   INDEX RANGE SCAN                    USER    MODEL_A_IDX     
                I am wondering if there is a way to create this index (or indexes) using SEM_APIS Package Subprograms?

                Thank you.
                • 5. Re: SPARQL Update with Jena Adapter
                  alwu-Oracle
                  alwu-Oracle Jun 7, 2013 5:54 PM (in response to martani)
                  Hi,

                  SEM_APIS package does not have this index creation. The reason is that this index belong more or less to the application area. One can, of course, get the underlying index DDL and run it in SQL*Plus.

                  Thanks,

                  Zhe Wu
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