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https://issues.apache.org/jira/browse/SOLR-1262?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13024930#comment-13024930
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Joachim Martin commented on SOLR-1262:
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I have been told by my Oracle DBA that DIH's use of Statement vs Prepared
Statement is causing serious problems on the database side. There is a
performance gain by not having to re-parse a prepared statement, but more
importantly, each Statement that needs to be re-parsed takes up space in the
cache. If you have repeating related entities (e.g. Author->Books[]), each
related query is a unique statement.
Many developers, myself included, would never consider writing a database app
without Prepared Statements for performance reasons. I think it's even more
important in a batch update situation where you are running N additional
related entity queries.
I like the syntax of MyBatis' mapped statements:
select field1, field2 from related_table where entity_id = #{id,
jdbcType=NUMERIC}
> DIH needs support for callable statements
> ------------------------------------------
>
> Key: SOLR-1262
> URL: https://issues.apache.org/jira/browse/SOLR-1262
> Project: Solr
> Issue Type: Improvement
> Components: contrib - DataImportHandler
> Affects Versions: 1.3
> Environment: linux
> mysql
> Reporter: Abdul Chaudhry
> Assignee: Noble Paul
> Priority: Minor
> Fix For: Next
>
>
> During an indexing run we noticed that we were spending a lot of time
> creating and tearing down queries in mysql
> The queries we are using are complex and involve joins spanning across
> multiple tables.
> We should support prepared statements in the data import handler via the
> data-config.xml file - for those databases that support prepared statements.
> We could add a new attribute to the entity entity in dataConfig - say -
> pquery or preparedQuery and then pass the prepared statement and have values
> filled in by the actual queries for each row using a placeholder - like a ?
> or something else.
> I would probably start by hacking class JdbcDataSource to try a test but was
> wondering if anyone had experienced this or had any suggestions or if there
> is something in the works that I missed - I couldn't find any other bugs
> mentioning using prepared statements for performance.
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