fix: Thread safe Clickhouse offline store #5710
Merged
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What this PR does / why we need it:
PR adjusts the Clickhouse offline store to be thread safe. Issue with the current implementation results in the issue as follows:
raise ProgrammingError('Attempt to execute concurrent queries within the same session.'if you bombard it -
feast serve- with concurrent requests, the under the hood threadpool is more than 1 thread by default (arbitrary number decided by uvicorn).as per Clickhouse docs here:
Solution - using threading.local() we can initialize a per-thread container for variables, to make sure we re-use the client on subsequent calls. Can we just drop the caching? Not really, unless the store is heavily refactored.
Which issue(s) this PR fixes:
No issue raised yet.
Misc