sqlite3 performance problems only in python
python.list at tim.thechases.com
Thu Jul 23 14:39:46 CEST 2009
> until now I used only small / simple databases in Python with sqlite3.
> Now I've a large and rather complex database.
> The most simple query (with just a result of 100 rows),
> takes about 70 seconds.
> And all that time is consumed in "cursor.fetchall"
> Using the same database in Delphi,
> using the same query,
> takes less than 5 seconds (including displaying the full table in a grid).
While it may seem obvious, are you doing anything time-consuming
with those results? Or have you tested just doing the fetchall()
without doing any further processing? I'm curious on the timing of
sql = "..."
start = time()
rows = cursor.fetchall()
end = time()
with no other processing. I regularly write sql that's fairly
complex and brings back somewhat large datasets (sometimes in
sqlite), and have never experienced problems with "simple
quer[ies] (with just a result of 100 rows" taking such
The answer from the above code will help determine whether it's
the sqlite portion that's crazy (and might need some well-placed
index statements; though if your Delphi code is fine, I suspect
not), or if it's your application code that goes off into left
field with the resulting data.
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