Oh boy. My latest update to my commercial app contained a database update. As 
SQLite 
doesn't offer a general enough ALTER TABLE implementation, my program makes a 
copy of 
the affected table(s), and then recreates the table definitions, and finally 
copies 
the data from the old to the new, and drops the old.

This has been working great for years. But for some reason (perhaps people's 
databases have grown much larger than they were before) the update for one 
customer 
took 45 minutes, even though the total number of rows copied was < 10K. The 
customer 
thought the program was nonresponsive, even though I have a throbber, and 
force-quit 
during the update, corrupting the data. 2 other customers did the same thing. 3 
other 
customers had no problem (not sure if their updates were relatively quick or 
not - 
I'm going to be calling them to find out).

These are all XP or Vista machines. Seems some of them are taking a seriously 
long 
time to do the update, while my testing on my Vista/XP boxes happens reasonably 
quickly. I acquired the database of that one customer that took 45 minutes on 
his 
system, and ran it on my Vista, Mac, and Linux systems. The Vista system took 7 
minutes, Mac 3 minutes, and Linux 2 minutes. I guess 10K rows in 7 minutes is 
in the 
realm of acceptable, but it still seems slow.

But what could cause such slow performance on my customer's system. I watched 
the 
process with LogMeIn, and had task manager open. CPU usage was only at like 10% 
during the process, and memory usage for the app stayed at a constant 69-70 MB. 
I 
didn't watch disk I/O (how would I do that remotely in Windows?)

Is there something in XP/Vista that would cause such severe slowdowns? The 
database 
lives (by default) in the user's %appdata% directory. I didn't notice any other 
process hogging resources.

Any ideas, other than making it clear that they need to wait for the updating 
to occur?

Paul
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