[jira] [Created] (SOLR-11772) Use JDBC-bind variables for DIH to improve performance with oracle db

["Karl Zweimüller (JIRA)" <ji...@apache.org>]

Karl Zweimüller created SOLR-11772:
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             Summary: Use JDBC-bind variables for DIH to improve performance with oracle db
                 Key: SOLR-11772
                 URL: https://issues.apache.org/jira/browse/SOLR-11772
             Project: Solr
          Issue Type: Improvement
      Security Level: Public (Default Security Level. Issues are Public)
          Components: contrib - DataImportHandler
            Reporter: Karl Zweimüller
            Priority: Minor


I just reduced the time for my full-import (solr 6.0.1) on an oracle-database for 1.4mio documents from 36 hours to 5 hours by setting the oracle session-parameter "CURSOR_SHARING=FORCE".
Here I found one with the same problem:
http://lucene.472066.n3.nabble.com/Optimizing-Dataimport-from-Oracle-cursor-sharing-changing-oracle-session-parameters-td4350601.html

I have 1.4 mio documents and for every document i need 12 queries to collect sub-information for the actual document.
This makes about 17mio sql-Statements to oracle for a full-import.

As DIH doesn't use bind-variables (https://docs.oracle.com/cd/B28359_01/appdev.111/b28765/addfunc.htm#TDPJD210), every select looks "different" for oracle and a full parse (analyze statement, get optimal query-plan,..) has to be done 17mio times.

By setting the session parameter "CURSOR_SHARING=FORCE", which can be done in an on_logon_trigger, oracle replaces all literals ins SQL with bind-variables and then can skip the hard-parse.

This reduced my full-import-time from 36 hours to 5 hours. (With this you get only 13 different sql-statements compared to 17mio different statements before.

As oracle states, that setting the CURSOR_SHARING=FORCE is only a workaround, it would be fine when DIH would use bind-variables for the variables.

Charly




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