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?
>>>
>>>
>>>
>>>
>>>
>>
>
>
This archive was generated by hypermail 2.0.0 : Thu Dec 24 2009 - 04:07:55 EST