Build options

Macros
#define	MDBX_OSX_WANNA_DURABILITY   0
#define	MDBX_OSX_WANNA_SPEED   1
#define	MDBX_APPLE_SPEED_INSTEADOF_DURABILITY   MDBX_OSX_WANNA_DURABILITY
#define	MDBX_ENV_CHECKPID   1
#define	MDBX_TXN_CHECKOWNER   1
#define	MDBX_TRUST_RTC   1
#define	MDBX_ENABLE_REFUND   1
#define	MDBX_ENABLE_PROFGC   0
#define	MDBX_ENABLE_PGOP_STAT   1
#define	MDBX_USE_MINCORE   1
#define	MDBX_USE_MINCORE_CONFIG   "AUTO=" MDBX_STRINGIFY(MDBX_USE_MINCORE)
#define	MDBX_ENABLE_BIGFOOT   1
#define	MDBX_DISABLE_VALIDATION   0
#define	MDBX_PNL_PREALLOC_FOR_RADIXSORT   1
#define	MDBX_DPL_PREALLOC_FOR_RADIXSORT   1
#define	MDBX_DML_PREALLOC_FOR_RADIXSORT   1
#define	MDBX_DPL_CACHE_NPAGES   0
#define	MDBX_AVOID_MSYNC   0
#define	MDBX_ENABLE_DBI_SPARSE   1
#define	MDBX_ENABLE_DBI_LOCKFREE   1
#define	MDBX_PNL_ASCENDING   0
#define	MDBX_WITHOUT_MSVC_CRT   0
#define	MDBX_ENVCOPY_WRITEBUF   1048576u
#define	MDBX_FORCE_ASSERTIONS   0
#define	MDBX_ASSUME_MALLOC_OVERHEAD   (sizeof(void *) * 2u)
#define	MDBX_HAVE_BUILTIN_CPU_SUPPORTS   0
#define	MDBX_NOSUCCESS_PURE_COMMIT   0
#define	MDBX_ENABLE_NON_READONLY_EXPORT   0
#define	MDBX_ENABLE_FAKE_NESTED_READONLY_TRANSACTIONS   0
#define	MDBX_ROUNDING_TO_ALLOCATION_GRANULARITY   0
#define	MDBX_LOCKING_WIN32FILES   -1
#define	MDBX_LOCKING_SYSV   5
#define	MDBX_LOCKING_POSIX1988   1988
#define	MDBX_LOCKING_POSIX2001   2001
#define	MDBX_LOCKING_POSIX2008   2008
#define	MDBX_LOCKING   MDBX_LOCKING_SYSV
#define	MDBX_USE_OFDLOCKS   0
#define	MDBX_USE_SENDFILE   0
#define	MDBX_USE_COPYFILERANGE   0
#define	MDBX_USE_FALLOCATE   0
#define	MDBX_USE_FALLOCATE_CONFIG   "AUTO=" MDBX_STRINGIFY(MDBX_USE_FALLOCATE)
#define	MDBX_HISTOGRAM_USING_128BIT   0
#define	MDBX_CPU_WRITEBACK_INCOHERENT   0
#define	MDBX_MMAP_INCOHERENT_FILE_WRITE   0
#define	MDBX_MMAP_INCOHERENT_CPU_CACHE   0
#define	MDBX_MMAP_NEEDS_JOLT   1
#define	MDBX_MMAP_NEEDS_JOLT_CONFIG   "AUTO=" MDBX_STRINGIFY(MDBX_MMAP_NEEDS_JOLT)
#define	MDBX_64BIT_ATOMIC   1
#define	MDBX_64BIT_CAS   1
#define	MDBX_UNALIGNED_OK   0 /* no unaligned access allowed */
#define	MDBX_CACHELINE_SIZE   64
#define	MDBX_AUXILARY_IOV_MAX   64
#define	MDBX_BUILD_METADATA   ""
#define	MDBX_DEBUG   0...2

Detailed Description

Copyright

SPDX-License-Identifier: Apache-2.0

Author

Леонид Юрьев aka Leonid Yuriev leo@y.nosp@m.urie.nosp@m.v.ru

Date

2015-2026

The libmdbx build options.

Macro Definition Documentation

MDBX_64BIT_ATOMIC

#define MDBX_64BIT_ATOMIC   1

MDBX_64BIT_CAS

#define MDBX_64BIT_CAS   1

MDBX_APPLE_SPEED_INSTEADOF_DURABILITY

#define MDBX_APPLE_SPEED_INSTEADOF_DURABILITY   MDBX_OSX_WANNA_DURABILITY

Choices MDBX_OSX_WANNA_DURABILITY or MDBX_OSX_WANNA_SPEED for OSX & iOS

MDBX_ASSUME_MALLOC_OVERHEAD

#define MDBX_ASSUME_MALLOC_OVERHEAD   (sizeof(void *) * 2u)

Presumed malloc size overhead for each allocation to adjust allocations to be more aligned.

MDBX_AUXILARY_IOV_MAX

#define MDBX_AUXILARY_IOV_MAX   64

MDBX_AVOID_MSYNC

#define MDBX_AVOID_MSYNC   0

Controls dirty pages tracking, spilling and persisting in MDBX_WRITEMAP.

In other words, disables in-memory database updating with consequent flush-to-disk/msync syscall.

0/OFF = Don't track dirty pages at all, don't spill ones, and use msync() to persist data. This is by-default on Linux and other systems where kernel provides properly LRU tracking and effective flushing on-demand.

1/ON = Tracking of dirty pages but with LRU labels for spilling and explicit persist ones by write(). This may be reasonable for goofy systems (Windows) which low performance of msync() and/or zany LRU tracking.

MDBX_BUILD_METADATA

#define MDBX_BUILD_METADATA   ""

MDBX_CACHELINE_SIZE

#define MDBX_CACHELINE_SIZE   64

MDBX_CPU_WRITEBACK_INCOHERENT

#define MDBX_CPU_WRITEBACK_INCOHERENT   0

MDBX_DEBUG

#define MDBX_DEBUG   0...2

Controls enabling of debugging features.

• MDBX_DEBUG = 0 (by default) Disables any debugging features at all, including logging and assertion controls. Logging level and corresponding debug flags changing by mdbx_setup_debug() will not have effect.
• MDBX_DEBUG > 0 Enables code for the debugging features (logging, assertions checking and internal audit). Simultaneously sets the default logging level to the MDBX_DEBUG value. Also enables MDBX_DBG_AUDIT if MDBX_DEBUG >= 2.

MDBX_DISABLE_VALIDATION

#define MDBX_DISABLE_VALIDATION   0

Disable some checks to reduce an overhead and detection probability of database corruption to a values closer to the LMDB.

MDBX_DML_PREALLOC_FOR_RADIXSORT

#define MDBX_DML_PREALLOC_FOR_RADIXSORT   1

MDBX_DPL_CACHE_NPAGES

#define MDBX_DPL_CACHE_NPAGES   0

MDBX_DPL_PREALLOC_FOR_RADIXSORT

#define MDBX_DPL_PREALLOC_FOR_RADIXSORT   1

MDBX_ENABLE_BIGFOOT

#define MDBX_ENABLE_BIGFOOT   1

Enables chunking long list of retired pages during huge transactions commit to avoid use sequences of pages.

MDBX_ENABLE_DBI_LOCKFREE

#define MDBX_ENABLE_DBI_LOCKFREE   1

Controls support of lock-free opening of DBI-handles and deferred destroying ones.

MDBX_ENABLE_DBI_SPARSE

#define MDBX_ENABLE_DBI_SPARSE   1

Controls a supporting sparse sets of DBI-handles to reduce transaction startup and processing overhead.

MDBX_ENABLE_FAKE_NESTED_READONLY_TRANSACTIONS

#define MDBX_ENABLE_FAKE_NESTED_READONLY_TRANSACTIONS   0

Enables fake nested read-only transactions, which are much cheaper but do not restore the state of cursors in case of transaction abortion.

MDBX_ENABLE_NON_READONLY_EXPORT

#define MDBX_ENABLE_NON_READONLY_EXPORT   0

if enabled then instead of the returned error MDBX_REMOTE, only a warning is issued, when the database being opened in non-read-only mode is located in a file system exported via NFS.

MDBX_ENABLE_PGOP_STAT

#define MDBX_ENABLE_PGOP_STAT   1

Controls gathering statistics for page operations.

MDBX_ENABLE_PROFGC

#define MDBX_ENABLE_PROFGC   0

Controls profiling of GC search and updates.

MDBX_ENABLE_REFUND

#define MDBX_ENABLE_REFUND   1

Controls online database auto-compactification during write-transactions.

MDBX_ENV_CHECKPID

#define MDBX_ENV_CHECKPID   1

Controls checking PID against reuse DB environment after the fork()

MDBX_ENVCOPY_WRITEBUF

#define MDBX_ENVCOPY_WRITEBUF   1048576u

Size of buffer used during copying a environment/database file.

MDBX_FORCE_ASSERTIONS

#define MDBX_FORCE_ASSERTIONS   0

Forces assertion checking.

MDBX_HAVE_BUILTIN_CPU_SUPPORTS

#define MDBX_HAVE_BUILTIN_CPU_SUPPORTS   0

If defined then enables integration with Valgrind, a memory analyzing tool. If defined then enables use C11 atomics, otherwise detects ones availability automatically. If defined then enables use the GCC's __builtin_cpu_supports() for runtime dispatching depending on the CPU's capabilities.

Note

Defining MDBX_HAVE_BUILTIN_CPU_SUPPORTS to 0 should avoided unless build for particular single-target platform, since on AMD64/x86 this disables dynamic choice (at runtime) of SSE2 / AVX2 / AVX512 instructions with fallback to non-accelerated baseline code.

MDBX_HISTOGRAM_USING_128BIT

#define MDBX_HISTOGRAM_USING_128BIT   0

MDBX_LOCKING

#define MDBX_LOCKING   MDBX_LOCKING_SYSV

Advanced: Choices the locking implementation (autodetection by default).

MDBX_LOCKING_POSIX1988

#define MDBX_LOCKING_POSIX1988   1988

POSIX-1 Shared anonymous semaphores for MDBX_LOCKING

MDBX_LOCKING_POSIX2001

#define MDBX_LOCKING_POSIX2001   2001

POSIX-2001 Shared Mutexes for MDBX_LOCKING

MDBX_LOCKING_POSIX2008

#define MDBX_LOCKING_POSIX2008   2008

POSIX-2008 Robust Mutexes for MDBX_LOCKING

MDBX_LOCKING_SYSV

#define MDBX_LOCKING_SYSV   5

SystemV IPC semaphores for MDBX_LOCKING

MDBX_LOCKING_WIN32FILES

#define MDBX_LOCKING_WIN32FILES   -1

Win32 File Locking API for MDBX_LOCKING

MDBX_MMAP_INCOHERENT_CPU_CACHE

#define MDBX_MMAP_INCOHERENT_CPU_CACHE   0

MDBX_MMAP_INCOHERENT_FILE_WRITE

#define MDBX_MMAP_INCOHERENT_FILE_WRITE   0

MDBX_MMAP_NEEDS_JOLT

#define MDBX_MMAP_NEEDS_JOLT   1

Assume system needs explicit syscall to sync/flush/write modified mapped memory.

MDBX_MMAP_NEEDS_JOLT_CONFIG

#define MDBX_MMAP_NEEDS_JOLT_CONFIG   "AUTO=" MDBX_STRINGIFY(MDBX_MMAP_NEEDS_JOLT)

MDBX_NOSUCCESS_PURE_COMMIT

#define MDBX_NOSUCCESS_PURE_COMMIT   0

if enabled then treats the commit of pure (nothing changes) transactions as special cases and return MDBX_RESULT_TRUE instead of MDBX_SUCCESS.

MDBX_OSX_WANNA_DURABILITY

#define MDBX_OSX_WANNA_DURABILITY   0

Using fcntl(F_FULLFSYNC) with 5-10 times slowdown

MDBX_OSX_WANNA_SPEED

#define MDBX_OSX_WANNA_SPEED   1

Using fsync() with chance of data lost on power failure

MDBX_PNL_ASCENDING

#define MDBX_PNL_ASCENDING   0

Controls sort order of internal page number lists. This mostly experimental/advanced option with not for regular MDBX users.

Warning

The database format depend on this option and libmdbx built with different option value are incompatible.

MDBX_PNL_PREALLOC_FOR_RADIXSORT

#define MDBX_PNL_PREALLOC_FOR_RADIXSORT   1

MDBX_ROUNDING_TO_ALLOCATION_GRANULARITY

#define MDBX_ROUNDING_TO_ALLOCATION_GRANULARITY   0

Forces rounding size of memory mapped regions and files to system allocation granularity rather to system page size.

In most operating systems, RAM is allocated in larger chunks consisting of several pages. Thus, rounding up to the size of the system page, rather than the actual size of the block used for memory allocation, does not save resources, but only hides what is really happening. On the other hand, system allocation granularity may depend not only on the type of operating system, but also on the version, settings, and amount of available resources (RAM), so increasing the rounding unit may lead to doubtful and unexpected behavior for the user.

MDBX_TRUST_RTC

#define MDBX_TRUST_RTC   1

Does a system have battery-backed Real-Time Clock or just a fake.

MDBX_TXN_CHECKOWNER

#define MDBX_TXN_CHECKOWNER   1

Controls checking transaction owner thread against misuse transactions from other threads.

MDBX_UNALIGNED_OK

#define MDBX_UNALIGNED_OK   0 /* no unaligned access allowed */

MDBX_USE_COPYFILERANGE

#define MDBX_USE_COPYFILERANGE   0

Advanced: Using copy_file_range() syscall (autodetection by default).

MDBX_USE_FALLOCATE

#define MDBX_USE_FALLOCATE   0

Advanced: Using posix_fallocate() or fcntl(F_PREALLOCATE) on OSX (autodetection by default).

MDBX_USE_FALLOCATE_CONFIG

#define MDBX_USE_FALLOCATE_CONFIG   "AUTO=" MDBX_STRINGIFY(MDBX_USE_FALLOCATE)

MDBX_USE_MINCORE

#define MDBX_USE_MINCORE   1

Controls using Unix' mincore() to determine whether DB-pages are resident in memory.

MDBX_USE_MINCORE_CONFIG

#define MDBX_USE_MINCORE_CONFIG   "AUTO=" MDBX_STRINGIFY(MDBX_USE_MINCORE)

MDBX_USE_OFDLOCKS

#define MDBX_USE_OFDLOCKS   0

Advanced: Using POSIX OFD-locks (autodetection by default).

MDBX_USE_SENDFILE

#define MDBX_USE_SENDFILE   0

Advanced: Using sendfile() syscall (autodetection by default).

MDBX_WITHOUT_MSVC_CRT

#define MDBX_WITHOUT_MSVC_CRT   0

Avoid dependence from MSVC CRT and use ntdll.dll instead.