circuit_cache.h File Reference

C-linkage interface to the in-process provenance circuit cache. More...

#include "provsql_utils.h"

Include dependency graph for circuit_cache.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Functions
bool	circuit_cache_create_gate (pg_uuid_t token, gate_type type, unsigned nb_children, pg_uuid_t *children)
	Insert a new gate into the circuit cache.
unsigned	circuit_cache_get_children (pg_uuid_t token, pg_uuid_t **children)
	Retrieve the children of a cached gate.
gate_type	circuit_cache_get_type (pg_uuid_t token)
	Retrieve the type of a cached gate.

Detailed Description

C-linkage interface to the in-process provenance circuit cache.

The circuit cache is a bounded, LRU-evicting in-memory store that avoids repeated round-trips to the mmap-backed persistent circuit storage for recently accessed gates. It is implemented in C++ (see CircuitCache.h / CircuitCache.cpp) but exposed to the C parts of the extension through this header.

Gates evicted from the cache are flushed to the background mmap worker via the shared-memory pipe. Lookups that miss the cache fall back to reading the mmap files directly.

Definition in file circuit_cache.h.

Function Documentation

circuit_cache_create_gate()

bool circuit_cache_create_gate	(	pg_uuid_t	token,
		gate_type	type,
		unsigned	nb_children,
		pg_uuid_t *	children
	)

Insert a new gate into the circuit cache.

Records the gate identified by token with the given type and nb_children children. If the cache is full the oldest entry is evicted (and flushed to persistent storage) to make room.

Parameters

token	UUID identifying the new gate.
type	Gate type (e.g. gate_input, gate_plus).
nb_children	Number of child gates.
children	Array of nb_children child UUIDs.

Returns

true if the gate was inserted, false if it was already present in the cache.

Definition at line 55 of file CircuitCache.cpp.

Here is the call graph for this function:

Here is the caller graph for this function:

circuit_cache_get_children()

unsigned circuit_cache_get_children	(	pg_uuid_t	token,
		pg_uuid_t **	children
	)

Retrieve the children of a cached gate.

Looks up token in the cache and, on a hit, allocates an array of child UUIDs in the current memory context and writes its address to *children.

Parameters

token	UUID of the gate to look up.
children	Output parameter: set to a freshly allocated array of child UUIDs on success; untouched on a cache miss.

Returns

Number of children found, or UINT_MAX on a cache miss.

Definition at line 60 of file CircuitCache.cpp.

Here is the call graph for this function:

Here is the caller graph for this function:

circuit_cache_get_type()

gate_type circuit_cache_get_type

(

pg_uuid_t

token

)

Retrieve the type of a cached gate.

Parameters

token

UUID of the gate to look up.

Returns

The gate_type of the gate, or gate_invalid on a miss.

Definition at line 76 of file CircuitCache.cpp.

Here is the call graph for this function:

Here is the caller graph for this function: