Re: out of memory using ResultIterator

From: Emanuele Maiarelli (emanuel..engozzi.com)
Date: Thu Dec 24 2009 - 04:02:59 EST

  • Next message: Andrey Razumovsky: "Re: out of memory using ResultIterator"

        I'll give a try once the project will me stable on the 2.0.4. This
    project uses ROP with a swing rich application, plus some webservices
    for batchjobs, are ROP still working good on 3.0
    as they works on 2.0.4?

    Andrus Adamchik ha scritto:
    > Sure. Hopefully within a couple of weeks 3.0 becomes Release Candidate
    > and final after that, so you may give it another look.
    >
    > For now I guess the only way is to write a custom query extending
    > SQLTemplate and overriding 'createSQLAction' to call 'setFetchSize' on
    > the JDBC statement. Implementing a custom SQLAction can be pretty
    > involved, however if you are doing a one-off thing, it is doable.
    >
    > Also I would recommend to switch to Cayenne 3.0 at least temporarily
    > to confirm that the fix I described is indeed working for you. There
    > may be some other things at play here. Who knows.
    >
    > Andrus
    >
    >
    > On Dec 24, 2009, at 10:48 AM, Emanuele Maiarelli wrote:
    >>
    >> I'm trying to figureout a solution using 2.0.4.
    >>
    >> I don't feel confortable in switching to 3.0 at this stage of the
    >> project.
    >>
    >>
    >> Thank you,
    >>
    >> Emanuele
    >> Andrus Adamchik ha scritto:
    >>> This is likely an issue with MySQL driver caching returned data. The
    >>> solution was implemented in Cayenne 3.0 (which is now in beta):
    >>>
    >>> query.setStatementFetchSize(1000);
    >>>
    >>> This propagates the fetch size setting to the JDBC statement,
    >>> reducing the driver memory footprint.
    >>>
    >>> Andrus
    >>>
    >>> On Dec 24, 2009, at 9:43 AM, Emanuele Maiarelli wrote:
    >>>
    >>>> im using cayenne 2.0.4, and i need to fetch an huge ammout of data,
    >>>> i did that way:
    >>>>
    >>>>
    >>>> public static StringBuffer traceProts;
    >>>>
    >>>>
    >>>> static {
    >>>> traceProts = new StringBuffer();
    >>>> traceProts.append("SELECT ");
    >>>> traceProts.append("PROTOCOLLI.* ");
    >>>> traceProts.append("FROM PROTOCOLLI, ");
    >>>> traceProts.append("( ");
    >>>> traceProts.append(" SELECT ");
    >>>> traceProts.append(" FORM_PROT_FK ");
    >>>> traceProts.append(" FROM ");
    >>>> traceProts.append(" ( ");
    >>>> traceProts.append(" SELECT ");
    >>>> traceProts.append(" FORM_PROT_FK,SUM(IF(ME_PK is not
    >>>> null,1,0)) AS ESPORTAZIONI ");
    >>>> traceProts.append(" FROM FORMULARI ");
    >>>> traceProts.append(" LEFT JOIN MOV_EXPORTED ON
    >>>> (FORM_PK=ME_FORMULARI_FK) ");
    >>>> traceProts.append(" GROUP BY FORM_PROT_FK ");
    >>>> traceProts.append(" ) ");
    >>>> traceProts.append(" EXPS ");
    >>>> traceProts.append(" WHERE ESPORTAZIONI=0 ");
    >>>> traceProts.append(") ");
    >>>> traceProts.append("UNEXP ");
    >>>> traceProts.append("where PROT_PK=UNEXP.FORM_PROT_FK");
    >>>> }
    >>>>
    >>>> this query returns an huge ammont of row,
    >>>>
    >>>> and im fetching row using IteratedQuery, that's the code im using
    >>>>
    >>>> StringBuffer mq=new StringBuffer();
    >>>> Vector<EXPProtocolli> toRet=new Vector<EXPProtocolli>();
    >>>> mq.append(traceProts);
    >>>> mq.append(" AND PROT_CHIUSO=true AND PROT_RIPARTITO=true");
    >>>> SQLTemplate rawSelect = new SQLTemplate(Protocolli.class,
    >>>> mq.toString());
    >>>> ResultIterator v=ctx.performIteratedQuery(rawSelect);
    >>>> while (v.hasNextRow())
    >>>> {
    >>>> EXPProtocolli prt=new EXPProtocolli();
    >>>> DataRow dataRow = (DataRow) v.nextDataRow();
    >>>>
    >>>> Protocolli p=(Protocolli)
    >>>> ctx.objectFromDataRow(Protocolli.class, dataRow,false);
    >>>>
    >>>> this.bindEXPProtMsg(p,prt);
    >>>> prt.setStato(ProtStato.PROT_CARICO_ESPORTABILE);
    >>>> toRet.add(prt);
    >>>> }
    >>>> return toRet;
    >>>>
    >>>> when running this method i always get an heap space problem
    >>>>
    >>>> java.lang.OutOfMemoryError: Java heap space
    >>>> at com.mysql.jdbc.MysqlIO.nextRowFast(MysqlIO.java:1621)
    >>>> at com.mysql.jdbc.MysqlIO.nextRow(MysqlIO.java:1398)
    >>>> at com.mysql.jdbc.MysqlIO.readSingleRowSet(MysqlIO.java:2816)
    >>>> at com.mysql.jdbc.MysqlIO.getResultSet(MysqlIO.java:467)
    >>>> at
    >>>> com.mysql.jdbc.MysqlIO.readResultsForQueryOrUpdate(MysqlIO.java:2510)
    >>>> at com.mysql.jdbc.MysqlIO.readAllResults(MysqlIO.java:1746)
    >>>> at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2135)
    >>>> at
    >>>> com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2542)
    >>>> at
    >>>> com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1734)
    >>>>
    >>>> at
    >>>> com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:995)
    >>>> at
    >>>> org.apache.cayenne.access.jdbc.SQLTemplateAction.execute(SQLTemplateAction.java:135)
    >>>>
    >>>> at
    >>>> org.apache.cayenne.access.jdbc.SQLTemplateAction.performAction(SQLTemplateAction.java:107)
    >>>>
    >>>> at
    >>>> org.apache.cayenne.access.DataNodeQueryAction.runQuery(DataNodeQueryAction.java:59)
    >>>>
    >>>> at
    >>>> org.apache.cayenne.access.DataNode.performQueries(DataNode.java:273)
    >>>> at
    >>>> org.apache.cayenne.access.DataDomainLegacyQueryAction.execute(DataDomainLegacyQueryAction.java:81)
    >>>>
    >>>> at
    >>>> org.apache.cayenne.access.DataDomain$1.transform(DataDomain.java:725)
    >>>> at
    >>>> org.apache.cayenne.access.DataDomain.runInTransaction(DataDomain.java:826)
    >>>>
    >>>> at
    >>>> org.apache.cayenne.access.DataDomain.performQueries(DataDomain.java:722)
    >>>>
    >>>> at
    >>>> org.apache.cayenne.access.DataContext.internalPerformIteratedQuery(DataContext.java:1329)
    >>>>
    >>>> at
    >>>> org.apache.cayenne.access.DataContext.performIteratedQuery(DataContext.java:1295)
    >>>>
    >>>> at
    >>>> services.EXP.Factory.getProtocolliCaricoNonEsp(Factory.java:85)
    >>>> at services.EXP.EXPServicePBE.getData(EXPServicePBE.java:54)
    >>>> at services.EXPExporter.processRequest(EXPExporter.java:52)
    >>>> ....
    >>>>
    >>>> the error is generated by: ResultIterator
    >>>> v=ctx.performIteratedQuery(rawSelect);
    >>>>
    >>>> any hints?
    >>>>
    >>>>
    >>>>
    >>>>
    >>>>
    >>>
    >>
    >>
    >



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