cache.h File Reference

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Macros
#define	GRN_CACHE_DEFAULT_MAX_N_ENTRIES   100

Typedefs
typedef struct _grn_cache	grn_cache
	Cache object.

Functions
GRN_API void	grn_set_default_cache_base_path (const char *base_path)
GRN_API const char *	grn_get_default_cache_base_path (void)
GRN_API grn_cache *	grn_cache_open (grn_ctx *ctx)
	Create a new cache object.
GRN_API grn_cache *	grn_persistent_cache_open (grn_ctx *ctx, const char *base_path)
GRN_API grn_rc	grn_cache_close (grn_ctx *ctx, grn_cache *cache)
	Free resourses of the cache.
GRN_API grn_rc	grn_cache_current_set (grn_ctx *ctx, grn_cache *cache)
	Set the current grn_cache object.
GRN_API grn_cache *	grn_cache_current_get (grn_ctx *ctx)
	Retrieve the current grn_cache object.
GRN_API grn_rc	grn_cache_default_reopen (void)
GRN_API grn_rc	grn_cache_set_max_n_entries (grn_ctx *ctx, grn_cache *cache, unsigned int n)
	Set the maximum number of entries in the grn_cache object.
GRN_API unsigned int	grn_cache_get_max_n_entries (grn_ctx *ctx, grn_cache *cache)
	Retrieve the maximum number of entries in the grn_cache object.

Macro Definition Documentation

GRN_CACHE_DEFAULT_MAX_N_ENTRIES

#define GRN_CACHE_DEFAULT_MAX_N_ENTRIES   100

Typedef Documentation

grn_cache

typedef struct _grn_cache grn_cache

Cache object.

You can create a new cache object using grn_cache_open, and free it using grn_cache_close.

Function Documentation

grn_cache_close()

GRN_API grn_rc grn_cache_close	(	grn_ctx *	ctx,
		grn_cache *	cache
	)

Free resourses of the cache.

Parameters

ctx	The context object.
cache	The cache object to be freed.

Returns

GRN_SUCCESS on success, the appropriate grn_rc on error.

grn_cache_current_get()

GRN_API grn_cache * grn_cache_current_get

(

grn_ctx *

ctx

)

Retrieve the current grn_cache object.

Parameters

ctx	The context object.

Returns

The grn_cache object is associated with the database that the context is using. If there is no specific cache, it returns the current cache which might be NULL.

grn_cache_current_set()

GRN_API grn_rc grn_cache_current_set	(	grn_ctx *	ctx,
		grn_cache *	cache
	)

Set the current grn_cache object.

Parameters

ctx	The context object.
cache	The new current cache object.

Returns

GRN_SUCCESS always.

grn_cache_default_reopen()

GRN_API grn_rc grn_cache_default_reopen

(

void

)

grn_cache_get_max_n_entries()

GRN_API unsigned int grn_cache_get_max_n_entries	(	grn_ctx *	ctx,
		grn_cache *	cache
	)

Retrieve the maximum number of entries in the grn_cache object.

Parameters

ctx	The context object.
cache	The cache object whose maximum entry count is to be retrieved.

Returns

The maximum number of entries for grn_cache object.

grn_cache_open()

GRN_API grn_cache * grn_cache_open

(

grn_ctx *

ctx

)

Create a new cache object.

It initializes a cache based on the current configuration or environment settings. The cache operates in either memory mode or persistent mode.

Cache Modes

Memory Cache:

• The same cache is shared within the same process.
• The same cache isn't shared across multiple processes.

Persistent Cache:

• The same cache is shared across multiple processes.
• Persistent cache is slightly slower than memory cache due to filesystem I/O.

Cache Mode Configuration

Cache mode can be configured in three ways:

Server/Daemon Option

When starting Groonga, use the --cache-base-path option to specify the cache base path. Setting this option to a valid path enables persistent cache mode.

Environment Variable

If the --cache-base-path option is not set when you start Groonga, the function checks the GRN_CACHE_TYPE environment variable.

• If GRN_CACHE_TYPE is set to persistent, it enables persistent cache mode without a specified base path.
• If GRN_CACHE_TYPE is set to any other value or is unset, it uses memory cache mode.

C API

Use grn_set_default_cache_base_path to override the configuration or environment settings at runtime.

Parameters

ctx	The context object used for memory allocation and error handling.

Returns

A newly created grn_cache object on success, NULL on error. The returned grn_cache object must be freed by grn_cache_close. See ctx->rc for error details.

grn_cache_set_max_n_entries()

GRN_API grn_rc grn_cache_set_max_n_entries	(	grn_ctx *	ctx,
		grn_cache *	cache,
		unsigned int	n
	)

Set the maximum number of entries in the grn_cache object.

Parameters

ctx	The context object.
cache	The cache object whose maximum entry count is updated.
n	The new maximum number of entries.

Returns

GRN_SUCCESS on success, the appropriate grn_rc on error.

grn_get_default_cache_base_path()

GRN_API const char * grn_get_default_cache_base_path

(

void

)

grn_persistent_cache_open()

GRN_API grn_cache * grn_persistent_cache_open	(	grn_ctx *	ctx,
		const char *	base_path
	)

grn_set_default_cache_base_path()

GRN_API void grn_set_default_cache_base_path

(

const char *

base_path

)