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TransitLayer realtime updates are slow and can be out of sync with Graph #2918
Description
As an intermediate step, we are currently mapping the Raptor TransitLayer from the old Graph representation of transit data. To get realtime updates for the TransitLayer, we implemented a GraphUpdater that periodically remaps the TransitLayer from the Graph.
When testing this with Norway data, there are two problems. First, it takes between 1-2 minutes to map the entire TransitLayer. This has to happen often, and consumes a lot of resources on the server.
The other problem is that this delays the effect of realtime updates and will for a time cause the data from the GraphIndex to become out of sync with the data in the TransitLayer. Both are used in the TransmodelAPI, so it is possible for a user to see data that is out of sync.
A better way is to only update the relevant parts of the TransitLayer, instead of mapping the entire data periodically.
Activity
t2gran commentedon Jan 6, 2020
Just to have everyone on the same page, the goal is to skip the mapping - there should be one model serving both the API needs and the Raptor routing. So this issue, is about solving making a short term solution to the RT performance issue described above.
gmellemstrand commentedon Feb 6, 2020
This is solved in #2919