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List:       sqlite-users
Subject:    [sqlite] Out of memory error on query returning no records
From:       Radcon Entec <radconentec () yahoo ! com>
Date:       2009-03-27 17:49:37
Message-ID: 368540.4163.qm () web43405 ! mail ! sp1 ! yahoo ! com
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I found the table that I wasn't closing properly, which was locking up my database.  \
Thanks again, Dr. Hipp, for pointing me in the right direction.

But I just stumbled on another problem.  It shouldn't show up in production, but it \
wouldn't be good to ignore it, either.  

The table I'm working with has 3 columns:  a tag_key, a value and a time.  The \
tag_key is a foreign key into another table that has 5 record, so the possible values \
of tag_key are 1, 2, 3, 4 and 5.  Data is added to this table in sets, one record for \
each possible tag key.  At our customer's site, this table is about 68 megabytes \
long, containing data from several months ago up to the current time.  For \
convenience in debugging, yesterday morning I stripped out all data except that \
recorded between midnight and the current time, so now it contains only about nine \
hours' worth of data.

The control I developed that displays the graph allows the user to select data up to \
one month old.  So, just for the heck of it, I asked for data about two weeks old.  \
This generated the following query:

select tag_key, value, julianday(value_timestamp) AS juliantime from trend_data where \
tag_key in (select tag_key from trend_pens where trend_key = 1) and \
datetime(value_timestamp, 'localtime') > '2009-02-25 17:26:42' and \
datetime(value_timestamp, 'localtime') < '2009-03-25 13:26:42'

There is no data in the trend_data table that is older than 2009-03-25 13:26:42, so \
this query should just return no records.  Instead, sqlite3 throws an out of memory \
error!  

I know this isn't very much to go on, but can anyone suggest anything I might be \
doing wrong that would cause this simple query to fail so badly?

My control is written in C++ using MS Visual Studio 6.

Thank you very much!

RobR



      
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