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Posted to user@empire-db.apache.org by Ivan Nemeth <iv...@gmail.com> on 2014/09/24 16:14:07 UTC
DBReader performance suggestion
Hi,
the DBReader can be much faster for resultsets with many columns if the
getFieldIndex(ColumnExpr c) method uses some kind of caching. The following
code is 10 times faster for a resultset with 20000 rows and 70 columns.
public class MyDBReader extends DBReader {
private static final long serialVersionUID = 1L;
private Map<ColumnExpr, Integer> fieldIndices = new HashMap<ColumnExpr,
Integer>();
@Override
public int getFieldIndex(ColumnExpr column) {
Integer i = fieldIndices.get(column);
if (i == null){
i = super.getFieldIndex(column);
fieldIndices.put(column, i);
}
return i;
}
}
What do you think?
Regards,
Ivan
Re: DBReader performance suggestion
Posted by Francis De Brabandere <fr...@gmail.com>.
Rainer, what do you think about this one?
Cheers,
F
On 29 September 2014 08:16, ivan nemeth <iv...@forumdigital.net> wrote:
> Hi Francis,
>
> ok, here it is:
>
> https://issues.apache.org/jira/browse/EMPIREDB-213
>
> Regards,
> Ivan
>
>
> On Sun, Sep 28, 2014 at 8:57 PM, Francis De Brabandere <fr...@gmail.com>
> wrote:
>>
>> Hi Ivan,
>>
>> Would you mind creating at ticket for this issue?
>> https://issues.apache.org/jira/browse/EMPIREDB
>>
>> Thanks,
>> Francis
>>
>> On 24 September 2014 16:14, Ivan Nemeth <iv...@gmail.com> wrote:
>> > Hi,
>> >
>> > the DBReader can be much faster for resultsets with many columns if the
>> > getFieldIndex(ColumnExpr c) method uses some kind of caching. The
>> > following
>> > code is 10 times faster for a resultset with 20000 rows and 70 columns.
>> >
>> > public class MyDBReader extends DBReader {
>> >
>> > private static final long serialVersionUID = 1L;
>> > private Map<ColumnExpr, Integer> fieldIndices = new HashMap<ColumnExpr,
>> > Integer>();
>> >
>> > @Override
>> > public int getFieldIndex(ColumnExpr column) {
>> > Integer i = fieldIndices.get(column);
>> > if (i == null){
>> > i = super.getFieldIndex(column);
>> > fieldIndices.put(column, i);
>> > }
>> > return i;
>> > }
>> >
>> > }
>> >
>> > What do you think?
>> >
>> > Regards,
>> > Ivan
>
>
Re: DBReader performance suggestion
Posted by ivan nemeth <iv...@forumdigital.net>.
Hi Francis,
ok, here it is:
https://issues.apache.org/jira/browse/EMPIREDB-213
Regards,
Ivan
On Sun, Sep 28, 2014 at 8:57 PM, Francis De Brabandere <fr...@gmail.com>
wrote:
> Hi Ivan,
>
> Would you mind creating at ticket for this issue?
> https://issues.apache.org/jira/browse/EMPIREDB
>
> Thanks,
> Francis
>
> On 24 September 2014 16:14, Ivan Nemeth <iv...@gmail.com> wrote:
> > Hi,
> >
> > the DBReader can be much faster for resultsets with many columns if the
> > getFieldIndex(ColumnExpr c) method uses some kind of caching. The
> following
> > code is 10 times faster for a resultset with 20000 rows and 70 columns.
> >
> > public class MyDBReader extends DBReader {
> >
> > private static final long serialVersionUID = 1L;
> > private Map<ColumnExpr, Integer> fieldIndices = new HashMap<ColumnExpr,
> > Integer>();
> >
> > @Override
> > public int getFieldIndex(ColumnExpr column) {
> > Integer i = fieldIndices.get(column);
> > if (i == null){
> > i = super.getFieldIndex(column);
> > fieldIndices.put(column, i);
> > }
> > return i;
> > }
> >
> > }
> >
> > What do you think?
> >
> > Regards,
> > Ivan
>
Re: DBReader performance suggestion
Posted by Francis De Brabandere <fr...@gmail.com>.
Hi Ivan,
Would you mind creating at ticket for this issue?
https://issues.apache.org/jira/browse/EMPIREDB
Thanks,
Francis
On 24 September 2014 16:14, Ivan Nemeth <iv...@gmail.com> wrote:
> Hi,
>
> the DBReader can be much faster for resultsets with many columns if the
> getFieldIndex(ColumnExpr c) method uses some kind of caching. The following
> code is 10 times faster for a resultset with 20000 rows and 70 columns.
>
> public class MyDBReader extends DBReader {
>
> private static final long serialVersionUID = 1L;
> private Map<ColumnExpr, Integer> fieldIndices = new HashMap<ColumnExpr,
> Integer>();
>
> @Override
> public int getFieldIndex(ColumnExpr column) {
> Integer i = fieldIndices.get(column);
> if (i == null){
> i = super.getFieldIndex(column);
> fieldIndices.put(column, i);
> }
> return i;
> }
>
> }
>
> What do you think?
>
> Regards,
> Ivan