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This new macro is able to perform a direct lookup from the local cache of injection points (refreshed each time a point is loaded or run), without touching the shared memory state of injection points at all. This works in combination with INJECTION_POINT_LOAD(), and it is better than INJECTION_POINT() in a critical section due to the fact that it would avoid all memory allocations should a concurrent detach happen since a LOAD(), as it retrieves a callback from the backend-private memory. The documentation is updated to describe in more details how to use this new macro with a load. Some tests are added to the module injection_points based on a new SQL function that acts as a wrapper of INJECTION_POINT_CACHED(). Based on a suggestion from Heikki Linnakangas. Author: Heikki Linnakangas, Michael Paquier Discussion: https://postgr.es/m/58d588d0-e63f-432f-9181-bed29313dece@iki.fi
46 lines
1.5 KiB
C
46 lines
1.5 KiB
C
/*-------------------------------------------------------------------------
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* injection_point.h
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* Definitions related to injection points.
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*
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* Copyright (c) 2001-2024, PostgreSQL Global Development Group
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*
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* src/include/utils/injection_point.h
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*-------------------------------------------------------------------------
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*/
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#ifndef INJECTION_POINT_H
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#define INJECTION_POINT_H
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/*
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* Injections points require --enable-injection-points.
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*/
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#ifdef USE_INJECTION_POINTS
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#define INJECTION_POINT_LOAD(name) InjectionPointLoad(name)
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#define INJECTION_POINT(name) InjectionPointRun(name)
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#define INJECTION_POINT_CACHED(name) InjectionPointCached(name)
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#else
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#define INJECTION_POINT_LOAD(name) ((void) name)
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#define INJECTION_POINT(name) ((void) name)
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#define INJECTION_POINT_CACHED(name) ((void) name)
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#endif
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/*
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* Typedef for callback function launched by an injection point.
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*/
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typedef void (*InjectionPointCallback) (const char *name,
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const void *private_data);
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extern Size InjectionPointShmemSize(void);
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extern void InjectionPointShmemInit(void);
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extern void InjectionPointAttach(const char *name,
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const char *library,
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const char *function,
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const void *private_data,
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int private_data_size);
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extern void InjectionPointLoad(const char *name);
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extern void InjectionPointRun(const char *name);
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extern void InjectionPointCached(const char *name);
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extern bool InjectionPointDetach(const char *name);
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#endif /* INJECTION_POINT_H */
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