What's the best way to buffer a large map?

[kitfox]

I have program that contains a QMap that uses a custom data structure as a key and maps to a float. (The key has a somewhat complex design). The program has grown to the point that I need to index about 7 million entries in my map, and this is causing me to run out of memory.

I'm thinking that I might need to store all this info in some sort of local database instead, but am unsure of the best way to go about this. I could use SQL, but I am worried that it might be slow. Does Qt provide a fast way to create a file-backed map?

[Christian Ehrlicher]

@kitfox said in What's the best way to buffer a large map?:

Does Qt provide a fast way to create a file-backed map?

No, you have to do it by your own. Maybe you can use QCache and load it from the db if it's no longer in the cache.

[ofmrew]

Have you reviewed the spacial database literature? It seems that you are discussing a common GIS issue.

[Kent-Dorfman]

I think if you've grown to the point of 7million keys then you're way into the realm of using a real database and using something like SQL queries to pull information.