I thought I had fixed the performance problem, but it is still there. What I am doing is opening 3 dependent queries after selecting a record in the main table. It takes 8 or 9 seconds to do the 3 calls to TQuery.Open. Any clues as to what I might be doing wrong? The sample queries done from sqlite3.exe return instantaneously, so I am concluding that I have not set something up correctly in the LCL.

Can you provide test data and a sample program ?
Without that, it's very hard to give recommendations.

The architecture of the sqlite components is not fundamentally different from the other database, and those do work instantaneously.

Michael.

I have a dummy database and complete program I can let you look at if you would like. Nothing particularly proprietary about the code; it's a trivial application. The database is the sensitive part, and I have it dummied out.

I posted the schema a few days ago, and I've added a zipcode table to that. I had initially thought I had solved the performance problem, but when I got to the client, and ran it on his machine (which is about 100x slower than mine). I had not noticed the lag on my machine, but it was really awful on his.

The whole project is in a 1.6Mb zip, expands to just over 7Mb. Would you like me to email it directly to you, or post it?

I have added some code to only open a query if the corresponding tabsheet is selected, which I think speeds things up sufficiently. Still would like to know why a TQuery component would take 2 or 3 seconds to open, even on a slow machine.

Here is the SQL from my address table query:

select * from addresses
where ID = :ID
order by atype,asof

"atype" is a string (home, work, etc.) and "asof" is a date.

The SQL for the other two queries is very similar.

In the synchronization procedure to set the :ID value for each query:

   closeDependentQueries;
   CurrentClientID := qClients.FieldByName('ID').AsInteger;
   qAddresses.Params.ParamByName('ID').Value := CurrentClientID;
   qCases.Params.ParamByName('ID').Value := CurrentClientID;
   qPhones.Params.ParamByName('ID').Value := CurrentClientID;

I have not yet played around with the foreign key stuff, and I'm not really sure how to enable & use foreign keys in SQLite, anyway.