Re: Unhandled exception in PGAdmin when opening 16-million-record table

Hey all,

Why not to use MVC approach by implementing a model, which uses, e.g.
scrollable cursors? I believe that wxWidgets supports MVC.

2010/10/30 Peter Geoghegan <peter(dot)geoghegan86(at)gmail(dot)com>

> On 29 October 2010 21:52, Rob Richardson <Rob(dot)Richardson(at)rad-con(dot)com>
> wrote:
> > A customer was reviewing the database that supports the application we
> have
> > provided. One of the tables is very simple, but has over 16 million
> > records. Here is the table's definition:
> >
> > CREATE TABLE feedback
> > (
> > charge integer,
> > elapsed_time integer, -- number of elapsed minutes since data began
> > recording
> > tag_type character varying(24), -- Description of tag being recorded
> > tag_value real, -- value of tag being recorded
> > status smallint, -- PLC Status, recorded with Control PV only
> > stack integer, -- Not used
> > heating smallint DEFAULT 0, -- 1 for heating, 0 for cooling
> > cooling smallint DEFAULT 0 -- not used
> > )
> >
> > As you see, there is no primary key. There is a single index, as
> follows:
> >
> > CREATE INDEX feedback_charge_idx
> > ON feedback
> > USING btree
> > (charge);
> > In PGAdmin, the customer selected this table and clicked the grid on the
> > toolbar, asking for all of the records in the table. After twenty
> minutes,
> > a message box appeared saying that an unhandled exception had happened.
> > There was no explanation of what the exception was. The database log
> does
> > not contain any information about it. The PGAdmin display did show a
> number
> > of records, leading me to believe that the error happened in PGAdmin
> rather
> > than anywhere in PostGres.
> >
> > Can anyone explain what is happening?
>
> Does WxWidgets/PgAdmin provide an overload of global operator new()
> that follows the pre-standard C++ behaviour of returning a null ptr,
> ala malloc()? C++ application frameworks that eschew exceptions often
> do. This sounds like an unhandled std::bad_alloc exception.
>
>
> Why don't we have some hard limit on the number of rows viewable in a
> table? Would that really be so terrible?
>
>
> --
> Regards,
> Peter Geoghegan
>
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--
// Dmitriy.