On 12-02-2013 13:29, shaung wrote:
On Tuesday, February 12, 2013 7:18:37 PM UTC+9, Simon King wrote:
If you add echo='debug' to your create_engine call, SA will log all
calls to the database and rows returned, which might give you an idea
of where all the time is being spent.
Thanks, Simon. I've looked through the debug log and found the reason.
It turns out that the table has several foreign key constraints,
and SA is inspecting all of the related tables and all the related
tables to the related tables...
There were 23 tables involved, which explained the long execution time.
So is there anything I can do about this?
I'm considering two possibilities:
1. Ignore the constraints to speed up
2. Or cache all the meta data to a disk file so no need to wait when
restarting the program
Either would be fine for me.
Is it possible?
I had a smilar problem.
I had a ms sql database that another application created and I need to
select data from it. There was lots of tables so I tried reflection but
it was slow so I decided to use sa declarative method. But declaring all
the tables again in python was too much work. I use sqlautocode to
generate declerative table classes and use them in my models with some
minor modifications. if the db structure does not change too often this
will speed up things.
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