FFT-95 Optimise edit forecast database queries #546
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so far so good. the issue is too many db queries. started at 9000+ now down to 450~. next steps is to look at the get_budget call
easy annotate sum for the budget has solved the n+1 finally turned my attention to the rest of the view added a selected_related room for more improvements down to 21 queries and no n+1
small js optimisation
add sentry database query tracking
CamLamb
approved these changes
Nov 29, 2024
SamDudley
changed the title
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I set out to improve the performance of the edit forecast page. On my local machine it took over 6 seconds just to fetch the initial HTML.
Our local dataset contains over 400 rows in the table on that page, so I suspected we had an n+1 database query problem. After some digging it turns out I was right and there were over 17,000 queries!
After a couple of days spent optimising code, mostly through the use of
select_relatedandprefetch_related, I've managed to get the number of queries down to 13 and the page load time down to around 300ms!Here is a brief list of the optimisations:
select_relatedandprefetch_relatedwhere neededcurrent_financial_yearon therequestobjectcached_propertyto view methods being used in the templatecurrent_financial_yearas context into the financial code serializerThere was a more ambitious optimising around the
current_financial_yearusing aContextVar, but I chose to leave it out and go with storing it on the request object as it's simpler.The react code is now the bottleneck on that page :)