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Class mdbx::cache_entry

ClassList > mdbx > cache_entry

Cache entry for the transparent read-your-writes caching, see txn::get_cached() andmdbx_cache_get() .More...

• #include <mdbx.h++>

Inherits the following classes: MDBX_cache_entry_t

Public Attributes inherited from MDBX_cache_entry_t

See MDBX_cache_entry_t

Type	Name
uint64_t	last_confirmed_txnid
uint32_t	length
size_t	offset
uint64_t	trunk_txnid

Public Functions

Type	Name
	cache_entry () noexcept
	cache_entry (const cache_entry &) noexcept
	cache_entry (cache_entry && other) noexcept
constexpr	cache_entry (const MDBX_cache_entry_t & ce) noexcept
uint64_t	last_confirmed () noexcept const Returns the recent transaction/MVCC-snapshot ID wherein the entry was checked and confirmed.
bool	notfound () noexcept const Returns true if the entry caches the "key not found" state.
cache_entry &	operator= (const cache_entry &) noexcept
cache_entry &	operator= (const MDBX_cache_entry_t & ce) noexcept
void	reset () noexcept Initializes the cache entry to the "no cached info" state.
uint64_t	transaction_id () noexcept const Returns the transaction/MVCC-snapshot ID of the internal structure that holds the cached data.

Detailed Description

A value type wrapping MDBX_cache_entry_t. Each entry is associated with a key and holds a lightweight "version stamp" plus the offset of the cached value inside the memory-mapped database file, so subsequent lookups stop as soon as they reach an unmodified page.

An entry must be initialized (reset()) before the first use. Entries may be placed in shared memory and used by multiple processes, though libmdbx does not provide such interaction management yet.

Public Functions Documentation

function cache_entry [1/4]

inline mdbx::cache_entry::cache_entry () noexcept

---

function cache_entry [2/4]

mdbx::cache_entry::cache_entry (
    const cache_entry &
) noexcept

---

function cache_entry [3/4]

inline mdbx::cache_entry::cache_entry (
    cache_entry && other
) noexcept

---

function cache_entry [4/4]

inline constexpr mdbx::cache_entry::cache_entry (
    const MDBX_cache_entry_t & ce
) noexcept

---

function last_confirmed

Returns the recent transaction/MVCC-snapshot ID wherein the entry was checked and confirmed.

inline uint64_t mdbx::cache_entry::last_confirmed () noexcept const

---

function notfound

Returns true if the entry caches the "key not found" state.

inline bool mdbx::cache_entry::notfound () noexcept const

---

function operator=

cache_entry & mdbx::cache_entry::operator= (
    const cache_entry &
) noexcept

---

function operator=

inline cache_entry & mdbx::cache_entry::operator= (
    const MDBX_cache_entry_t & ce
) noexcept

---

function reset

Initializes the cache entry to the "no cached info" state.

inline void mdbx::cache_entry::reset () noexcept

---

function transaction_id

Returns the transaction/MVCC-snapshot ID of the internal structure that holds the cached data.

inline uint64_t mdbx::cache_entry::transaction_id () noexcept const

---

Friends Documentation

friend operator!=

inline bool mdbx::cache_entry::operator!= (
    const cache_entry & a,
    const cache_entry & b
) noexcept

---

friend operator==

inline bool mdbx::cache_entry::operator== (
    const cache_entry & a,
    const cache_entry & b
) noexcept

---

---

The documentation for this class was generated from the following file docs/mdbx.h++