mdbx::env::geometry Struct Reference

Database geometry for size management. More...

#include <mdbx.h++>

Classes
struct	size
	Tagged type for output to std::ostream. More...

Public Types
enum	: intptr_t {   default_value = -1 , minimal_value = 0 , maximal_value = INTPTR_MAX , kB = 1000 ,   MB = kB * 1000 , GB = MB * 1000 , KiB = 1024 , MiB = KiB << 10 ,   GiB = MiB << 10 }

Public Member Functions
geometry &	make_fixed (intptr_t size) noexcept
geometry &	make_dynamic (intptr_t lower=minimal_value, intptr_t upper=maximal_value) noexcept
constexpr	geometry () noexcept
constexpr	geometry (const geometry &) noexcept=default
constexpr	geometry (intptr_t size_lower, intptr_t size_now=default_value, intptr_t size_upper=maximal_value, intptr_t growth_step=default_value, intptr_t shrink_threshold=default_value, intptr_t pagesize=default_value) noexcept

Public Attributes
intptr_t	size_lower {minimal_value}
	The lower bound of database size in bytes.
intptr_t	size_now {default_value}
	The size in bytes to setup the database size for now.
intptr_t	size_upper {maximal_value}
	The upper bound of database size in bytes.
intptr_t	growth_step {default_value}
	The growth step in bytes, must be greater than zero to allow the database to grow.
intptr_t	shrink_threshold {default_value}
	The shrink threshold in bytes, must be greater than zero to allow the database to shrink.
intptr_t	pagesize {default_value}
	The database page size for new database creation or default_value otherwise.

Detailed Description

Database geometry for size management.

See also

env_managed::create_parameters

env_managed::env_managed(const ::std::string &pathname, const create_parameters &, const operate_parameters &, bool accede)

Member Enumeration Documentation

anonymous enum

anonymous enum : intptr_t

Enumerator
default_value	Means "keep current or use default".
minimal_value	Means "minimal acceptable".
maximal_value	Means "maximal acceptable".
kB	\(10^{3}\) bytes (0x03E8)
MB	\(10^{6}\) bytes (0x000F_4240)
GB	\(10^{9}\) bytes (0x3B9A_CA00)
KiB	\(2^{10}\) bytes (0x0400)
MiB	\(2^{20}\) bytes (0x0010_0000)
GiB	\(2^{30}\) bytes (0x4000_0000)

Constructor & Destructor Documentation

geometry() [1/3]

constexpr mdbx::env::geometry::geometry ( )

inlineconstexprnoexcept

geometry() [2/3]

constexpr mdbx::env::geometry::geometry ( const geometry &  )

constexprdefaultnoexcept

geometry() [3/3]

constexpr mdbx::env::geometry::geometry ( intptr_t  size_lower, intptr_t  size_now = default_value, intptr_t  size_upper = maximal_value, intptr_t  growth_step = default_value, intptr_t  shrink_threshold = default_value, intptr_t  pagesize = default_value  )

inlineconstexprnoexcept

Member Data Documentation

growth_step

intptr_t mdbx::env::geometry::growth_step {default_value}

The growth step in bytes, must be greater than zero to allow the database to grow.

pagesize

intptr_t mdbx::env::geometry::pagesize {default_value}

The database page size for new database creation or default_value otherwise.

Must be power of 2 in the range between MDBX_MIN_PAGESIZE and MDBX_MAX_PAGESIZE.

shrink_threshold

intptr_t mdbx::env::geometry::shrink_threshold {default_value}

The shrink threshold in bytes, must be greater than zero to allow the database to shrink.

size_lower

intptr_t mdbx::env::geometry::size_lower {minimal_value}

The lower bound of database size in bytes.

size_now

intptr_t mdbx::env::geometry::size_now {default_value}

The size in bytes to setup the database size for now.

It is recommended always pass default_value in this argument except some special cases.

size_upper

intptr_t mdbx::env::geometry::size_upper {maximal_value}

The upper bound of database size in bytes.

It is recommended to avoid change upper bound while database is used by other processes or threaded (i.e. just pass default_value in this argument except absolutely necessary). Otherwise you must be ready for MDBX_UNABLE_EXTEND_MAPSIZE error(s), unexpected pauses during remapping and/or system errors like "address busy", and so on. In other words, there is no way to handle a growth of the upper bound robustly because there may be a lack of appropriate system resources (which are extremely volatile in a multi-process multi-threaded environment).

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The documentation for this struct was generated from the following file:

• mdbx.h++