CircuitCache.h File Reference

LRU in-process cache for recently created provenance circuit gates. More...

#include "provsql_utils_cpp.h"
#include <optional>
#include <utility>
#include <vector>
#include <boost/multi_index_container.hpp>
#include <boost/multi_index/hashed_index.hpp>
#include <boost/multi_index/member.hpp>
#include <boost/multi_index/sequenced_index.hpp>

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Classes
struct	CircuitCacheInfos
	All information stored for a single gate in the circuit cache. More...
class	CircuitCache
	Bounded LRU cache mapping gate UUIDs to their CircuitCacheInfos. More...

Detailed Description

LRU in-process cache for recently created provenance circuit gates.

Reading gates from the mmap-backed persistent storage is relatively expensive. The CircuitCache stores the most recently created gates in an in-memory Boost multi-index container so that subsequent lookups within the same backend can skip the IPC round-trip to the background worker.

The cache is bounded by a fixed byte budget. When inserting a new gate would exceed the budget the oldest entry (FIFO order) is evicted. Eviction simply drops the entry: the cache is a read accelerator on top of a write-through design (every create_gate goes to the worker via IPC regardless of cache state, see provsql_mmap.c), so the worker already holds every gate the cache ever did and no flush hook is required.

The C-linkage wrapper functions in circuit_cache.h provide the interface used by the C portions of the extension.

Definition in file CircuitCache.h.