I just tried a revised version of the cache consumer method as follows:
def Record_entries_count(self):
# import pdb; pdb.set_trace()
db = cherrypy.request.db_session
query_subset = db.query(MyClass).merge_result(self.
search_result_cache)
result = query_subset.count()
return result
However, this gives me the following error:
AttributeError: 'list_iterator' object has no attribute 'count'
Why does `merge_result` return a list_iterator instead of the Query object
itself? How can I perform a .count() method in this case? Thanks.
On Thursday, July 13, 2017 at 4:38:19 PM UTC-7, Jinghui Niu wrote:
>
> I have a web application served by cherrypy (, which is multi-threaded. )
>
> I'm trying to cache a set of rows queried from database using
> `self.search_result_cache` variable on the GUI_Server object. On my
> front-end, the web first request `list_entries` to prepare the rows and
> stores them on `self.search_result_cache`. After that, on user's mouse
> click the front-end initiats another request calling
> `Record_entries_count`, which is expected to revive the Query from
> `self.search_result_cache` and continue on to do some data refining, e.g.
> summing up the count in this case.
>
> class GUI_Server:
>
>
> def __init__(self):
> self.search_result_cache = None
>
>
> @cherrypy.expose
> def list_entries(self, **criteriaDICT):
> # always store the result to self cache
>
> ...
>
>
> db = cherrypy.request.db_session
>
>
> filter_func = getattr(self, 'filterCriteria_' + classmodel_obj.
> __name__)
> queryOBJ = filter_func(criteriaDICT, queryOBJ)
> self.search_result_cache = queryOBJ
> db.expunge_all()
>
> ....
>
> def Record_entries_count(self):
> db = cherrypy.request.db_session
> query_subset = self.search_result_cache
> result = query_subset.count()
> return result
>
>
> But this doesn't work. It always give me an error:
>
> sqlite3.ProgrammingError: SQLite objects created in a thread can only be used
> in that same thread.The object was created in thread id 139937752020736 and
> this is thread id 139938238535424
>
> I am already using `scoped_session` for each request session. I don't
> understand why I got this error.
>
>
> What is the best pratice to cache queried result across different request
> sessions like this? Thanks a lot.
>
>
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