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efficient / libcuckoo

A high-performance, concurrent hash table
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upsert reentrancy? #127

Closed graehl closed 4 years ago

graehl commented 4 years ago

Just a question: if the constructor (or update fn) for a value causes another modification to the cuckoohash_map (say it's global), will corruption or deadlock ensue, or will the two or more insert/update both succeed?

manugoyal commented 4 years ago

Hey @graehl! Unfortunately we make no guarantees about mutating the hashtable within a callback or item constructor. The operation is performed under a non-reentrant spinlock, so if a hashtable operation called within the callback needs to access the same lock, it will never complete.

graehl commented 4 years ago

Thanks, I figured in absence of guarantee that was the case.

On Wed, Jul 1, 2020 at 7:30 PM Manu Goyal notifications@github.com wrote:

Hey @graehl https://github.com/graehl! Unfortunately we make no guarantees about mutating the hashtable within a callback or item constructor. The operation is performed under a non-reentrant spinlock, so if a hashtable operation called within the callback needs to access the same lock, it will never complete.

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