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mdbx: refine mdbx.h and error strings (1 of 5).

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Change-Id: Iaa6c4afeb9268d916ef1e8e23fdf12b7f603869f
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Leonid Yuriev 2019-09-12 03:30:10 +03:00
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mdbx.h
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@ -1,69 +1,15 @@
/* LICENSE AND COPYRUSTING *****************************************************
/**** BRIEFLY ******************************************************************
*
* Copyright 2015-2019 Leonid Yuriev <leo@yuriev.ru>
* and other libmdbx authors: please see AUTHORS file.
* All rights reserved.
* libmdbx is superior to LMDB in terms of features and reliability,
* not inferior in performance. libmdbx works on Linux, FreeBSD, MacOS X
* and other systems compliant with POSIX.1-2008, but also support
* Windows as a complementary platform.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted only as authorized by the OpenLDAP
* Public License.
* Look below for API description, for other information (build, embedding and
* amalgamation, improvements over LMDB, benchmarking, etc) please refer to
* README.md at https://abf.io/erthink/libmdbx.
*
* A copy of this license is available in the file LICENSE in the
* top-level directory of the distribution or, alternatively, at
* <http://www.OpenLDAP.org/license.html>.
*
* ---
*
* This code is derived from "LMDB engine" written by
* Howard Chu (Symas Corporation), which itself derived from btree.c
* written by Martin Hedenfalk.
*
* ---
*
* Portions Copyright 2011-2015 Howard Chu, Symas Corp. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted only as authorized by the OpenLDAP
* Public License.
*
* A copy of this license is available in the file LICENSE in the
* top-level directory of the distribution or, alternatively, at
* <http://www.OpenLDAP.org/license.html>.
*
* ---
*
* Portions Copyright (c) 2009, 2010 Martin Hedenfalk <martin@bzero.se>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
/* ACKNOWLEDGEMENTS ************************************************************
*
* Howard Chu (Symas Corporation) - the author of LMDB,
* from which originated the MDBX in 2015.
*
* Martin Hedenfalk <martin@bzero.se> - the author of `btree.c` code,
* which was used for begin development of LMDB. */
#pragma once
#ifndef LIBMDBX_H
#define LIBMDBX_H
/*******************************************************************************
*
* libmdbx is superior to LMDB in terms of features and reliability, not
* inferior in performance. libmdbx works on Linux, FreeBSD, MacOS X and other
* systems compliant with POSIX.1-2008, but also support Windows as a
* complementary platform.
* ---
*
* The next version is under active non-public development and will be released
* as MithrilDB and libmithrildb for libraries & packages. Admittedly mythical
@ -77,8 +23,230 @@
*
* The Future will (be) Positive. Всё будет хорошо.
*
*
**** INTRODUCTION *************************************************************
*
* // For the most part, this section is a copy of the corresponding text
* // from LMDB description, but with some edits reflecting the improvements
* // and enhancements were made in MDBX.
*
* MDBX is a Btree-based database management library modeled loosely on the
* BerkeleyDB API, but much simplified. The entire database (aka "environment")
* is exposed in a memory map, and all data fetches return data directly from
* the mapped memory, so no malloc's or memcpy's occur during data fetches.
* As such, the library is extremely simple because it requires no page caching
* layer of its own, and it is extremely high performance and memory-efficient.
* It is also fully transactional with full ACID semantics, and when the memory
* map is read-only, the database integrity cannot be corrupted by stray pointer
* writes from application code.
*
* The library is fully thread-aware and supports concurrent read/write access
* from multiple processes and threads. Data pages use a copy-on-write strategy
* so no active data pages are ever overwritten, which also provides resistance
* to corruption and eliminates the need of any special recovery procedures
* after a system crash. Writes are fully serialized; only one write transaction
* may be active at a time, which guarantees that writers can never deadlock.
* The database structure is multi-versioned so readers run with no locks;
* writers cannot block readers, and readers don't block writers.
*
* Unlike other well-known database mechanisms which use either write-ahead
* transaction logs or append-only data writes, MDBX requires no maintenance
* during operation. Both write-ahead loggers and append-only databases require
* periodic checkpointing and/or compaction of their log or database files
* otherwise they grow without bound. MDBX tracks free pages within the database
* and re-uses them for new write operations, so the database size does not grow
* without bound in normal use. It is worth noting that the "next" version
* libmdbx (MithrilDB) will solve this problem.
*
* The memory map can be used as a read-only or read-write map. It is read-only
* by default as this provides total immunity to corruption. Using read-write
* mode offers much higher write performance, but adds the possibility for stray
* application writes thru pointers to silently corrupt the database.
* Of course if your application code is known to be bug-free (...) then this is
* not an issue.
*
* If this is your first time using a transactional embedded key/value store,
* you may find the "GETTING STARTED" section below to be helpful.
*
* ---
* Restrictions and Caveats (in addition to those listed for some functions):
*
* - Troubleshooting the LCK-file.
* 1. A broken LCK-file can cause sync issues, including appearance of
* wrong/inconsistent data for readers. When database opened in the
* cooperative read-write mode the LCK-file requires to be mapped to
* memory in read-write access. In this case it is always possible for
* stray/malfunctioned application could writes thru pointers to
* silently corrupt the LCK-file.
*
* Unfortunately, there is no any portable way to prevent such
* corruption, since the LCK-file is updated concurrently by
* multiple processes in a lock-free manner and any locking is
* unwise due to a large overhead.
*
* The "next" version of libmdbx (MithrilDB) will solve this issue.
*
* Workaround: Just make all programs using the database close it;
* the LCK-file is always reset on first open.
*
* 2. Stale reader transactions left behind by an aborted program cause
* further writes to grow the database quickly, and stale locks can
* block further operation.
* MDBX checks for stale readers while opening environment and before
* growth the database. But in some cases, this may not be enough.
*
* Workaround: Check for stale readers periodically, using the
* mdbx_reader_check() function or the mdbx_stat tool.
*
* 3. Stale writers will be cleared automatically by MDBX on supprted
* platforms. But this is platform-specific, especially of
* implementation of shared POSIX-mutexes and support for robust
* mutexes. For instance there are no known issues on Linux, OSX,
* Windows and FreeBSD.
*
* Workaround: Otherwise just make all programs using the database
* close it; the LCK-file is always reset on first open
* of the environment.
*
* - Do not use MDBX databases on remote filesystems, even between processes
* on the same host. This breaks file locks on some platforms, possibly
* memory map sync, and certainly sync between programs on different hosts.
*
* On the other hand, MDBX support the exclusive database operation over
* a network, and cooperative read-only access to the database placed on
* a read-only network shares.
*
* - There is no pure read-only mode in a normal explicitly way, since
* readers need write access to LCK-file to be ones visible for writer.
* MDBX always tries to open/create LCK-file for read-write, but switches
* to without-LCK mode on appropriate errors (EROFS, EACCESS, EPERM)
* if the read-only mode was requested by the MDBX_RDONLY flag which is
* described below.
*
* The "next" version of libmdbx (MithrilDB) will solve this issue.
*
* - A thread can only use one transaction at a time, plus any nested
* read-write transactions in the non-writemap mode. Each transaction
* belongs to one thread. The MDBX_NOTLS flag changes this for read-only
* transactions. See below.
*
* - MDBX_env instance(s) should not be used in child processes after fork().
* It would be insane to call fork() and any MDBX-functions simultaneously
* from multiple threads. The best way is to prevent the presence of open
* MDBX-instances during fork().
*
* The MDBX_TXN_CHECKPID build-time option, which is ON by default on
* non-Windows platforms (i.e. where fork() is available), enables PID
* checking at a few critical points. But this does not give any guarantees,
* but only allows you to detect such errors a little sooner. Depending on
* the platform, you should expect an application crash and/or database
* corruption in such cases.
*
* On the other hand, MDBX allow calling mdbx_close_env() in such cases to
* release resources, but no more and in general this is a wrong way.
*
* - Do not have open an MDBX database twice in the same process at
* the same time. Not even from a plain open() call - close()ing it
* breaks POSIX's fcntl() advisory locking. It is OK to reopen it after
* fork() or exec(), since the opened files has FD_CLOEXEC set.
*
* Unlike the LMDB, the MDBX uses the "Open file description" locks (aka
* OFD-locks) when ones available, also performing additional checks against
* double-opening.
*
* - Avoid long-lived transactions, especially in the scenarios with a high
* rate of write transactions. Read transactions prevent reuse of pages
* freed by newer write transactions, thus the database can grow quickly.
* Write transactions prevent other write transactions, since writes are
* serialized.
*
* The "next" version of libmdbx (MithrilDB) will solve this issue
* for read-only transactions.
*
* - Avoid suspending a process with active transactions. These would then be
* "long-lived" as above.
*
* The "next" version of libmdbx (MithrilDB) will solve this issue.
*
* - Avoid aborting a process with an active read-only transaction in scenaries
* with high rate of write transactions. The transaction becomes "long-lived"
* as above until a check for stale readers is performed or the LCK-file is
* reset, since the process may not remove it from the lockfile. This does
* not apply to write transactions if the system clears stale writers, see
* above.
*
* - An MDBX database configuration will often reserve considerable unused
* memory address space and maybe file size for future growth. This does
* not use actual memory or disk space, but users may need to understand
* the difference so they won't be scared off.
*
**** GETTING STARTED **********************************************************
*
* TBD
*
**** LICENSE AND COPYRUSTING **************************************************
*
* Copyright 2015-2019 Leonid Yuriev <leo@yuriev.ru>
* and other libmdbx authors: please see AUTHORS file.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted only as authorized by the OpenLDAP
* Public License.
*
* A copy of this license is available in the file LICENSE in the
* top-level directory of the distribution or, alternatively, at
* <http://www.OpenLDAP.org/license.html>.
*
* ---
*
* This code is derived from "LMDB engine" written by
* Howard Chu (Symas Corporation), which itself derived from btree.c
* written by Martin Hedenfalk.
*
* ---
*
* Portions Copyright 2011-2015 Howard Chu, Symas Corp. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted only as authorized by the OpenLDAP
* Public License.
*
* A copy of this license is available in the file LICENSE in the
* top-level directory of the distribution or, alternatively, at
* <http://www.OpenLDAP.org/license.html>.
*
* ---
*
* Portions Copyright (c) 2009, 2010 Martin Hedenfalk <martin@bzero.se>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
*
**** ACKNOWLEDGEMENTS *********************************************************
*
* Howard Chu (Symas Corporation) - the author of LMDB,
* from which originated the MDBX in 2015.
*
* Martin Hedenfalk <martin@bzero.se> - the author of `btree.c` code,
* which was used for begin development of LMDB.
*
******************************************************************************/
#pragma once
#ifndef LIBMDBX_H
#define LIBMDBX_H
#ifdef _MSC_VER
#pragma warning(push, 1)
#pragma warning(disable : 4548) /* expression before comma has no effect; \
@ -201,6 +369,7 @@ typedef pthread_t mdbx_tid_t;
extern "C" {
#endif
/* MDBX version information. */
typedef struct mdbx_version_info {
uint8_t major;
uint8_t minor;
@ -214,7 +383,11 @@ typedef struct mdbx_version_info {
} git;
const char *sourcery /* sourcery anchor for pinning */;
} mdbx_version_info;
extern LIBMDBX_API const mdbx_version_info mdbx_version;
/* MDBX build information.
* WARNING: Some strings could be NULL in case no corresponding information was
* provided at build time (i.e. flags). */
typedef struct mdbx_build_info {
const char *datetime /* build timestamp (ISO-8601 or __DATE__ __TIME__) */;
const char *target /* cpu/arch-system-config triplet */;
@ -223,22 +396,48 @@ typedef struct mdbx_build_info {
const char *flags /* CFLAGS */;
} mdbx_build_info;
extern LIBMDBX_API const mdbx_version_info mdbx_version;
extern LIBMDBX_API const mdbx_build_info mdbx_build;
#if defined(_WIN32) || defined(_WIN64)
#if !MDBX_BUILD_SHARED_LIBRARY
/* Dll initialization callback for ability to dynamically load MDBX DLL by
* LoadLibrary() on Windows versions before Windows Vista. This function MUST be
* called once from DllMain() for each reason (DLL_PROCESS_ATTACH,
* DLL_PROCESS_DETACH, DLL_THREAD_ATTACH and DLL_THREAD_DETACH). Do this
* carefully and ONLY when actual Windows version don't support initialization
* via "TLS Directory" (e.g .CRT$XL[A-Z] sections in executable or dll file). */
/* MDBX internally uses global and thread local storage destructors to
* automatically (de)initialization, releasing reader lock table slots
* and so on.
*
* If MDBX builded as a DLL this is done out-of-the-box by DllEntry() function,
* which called automatically by Windows core with passing corresponding reason
* argument.
*
* Otherwise, if MDBX was builded not as a DLL, some black magic
* may be required depending of Windows version:
* - Modern Windows versions, including Windows Vista and later, provides
* support for "TLS Directory" (e.g .CRT$XL[A-Z] sections in executable
* or dll file). In this case, MDBX capable of doing all automatically,
* and you do not need to call mdbx_dll_callback().
* - Obsolete versions of Windows, prior to Windows Vista, REQUIRES calling
* mdbx_dll_callback() manually from corresponding DllMain() or WinMain()
* of your DLL or application.
* - This behavior is under control of the MODX_CONFIG_MANUAL_TLS_CALLBACK
* option, which is determined by default according to the target version
* of Windows at build time.
* But you may override MODX_CONFIG_MANUAL_TLS_CALLBACK in special cases.
*
* Therefore, building MDBX as a DLL is recommended for all version of Windows.
* So, if you doubt, just build MDBX as the separate DLL and don't worry. */
#ifndef MDBX_CONFIG_MANUAL_TLS_CALLBACK
#if defined(_WIN32_WINNT_VISTA) && WINVER >= _WIN32_WINNT_VISTA
/* As described above mdbx_dll_callback() is NOT needed forWindows Vista
* and later. */
#define MDBX_CONFIG_MANUAL_TLS_CALLBACK 0
#else
/* As described above mdbx_dll_callback() IS REQUIRED for Windows versions
* prior to Windows Vista. */
#define MDBX_CONFIG_MANUAL_TLS_CALLBACK 1
#endif
#endif /* MDBX_CONFIG_MANUAL_TLS_CALLBACK */
#if MDBX_CONFIG_MANUAL_TLS_CALLBACK
void LIBMDBX_API NTAPI mdbx_dll_callback(PVOID module, DWORD reason,
PVOID reserved);
@ -246,12 +445,7 @@ void LIBMDBX_API NTAPI mdbx_dll_callback(PVOID module, DWORD reason,
#endif /* !MDBX_BUILD_SHARED_LIBRARY */
#endif /* Windows */
/* The name of the lock file in the DB environment */
#define MDBX_LOCKNAME "/mdbx.lck"
/* The name of the data file in the DB environment */
#define MDBX_DATANAME "/mdbx.dat"
/* The suffix of the lock file when no subdir is used */
#define MDBX_LOCK_SUFFIX "-lck"
/**** TOP-LEVEL STRUCTURES ****************************************************/
/* Opaque structure for a database environment.
*
@ -265,8 +459,11 @@ typedef struct MDBX_env MDBX_env;
* read-only or read-write. */
typedef struct MDBX_txn MDBX_txn;
/* A handle for an individual database in the DB environment. */
/* A handle for an individual database (key-value spaces) in the DB environment.
* Zero handle is used internally (hidden Garbage Collection DB).
* So, any valid DBI-handle great than 0 and less than or equal MDBX_MAX_DBI. */
typedef uint32_t MDBX_dbi;
#define MDBX_MAX_DBI UINT32_C(32765)
/* Opaque structure for navigating through a database */
typedef struct MDBX_cursor MDBX_cursor;
@ -298,23 +495,75 @@ typedef struct iovec MDBX_val;
/* A callback function used to compare two keys in a database */
typedef int(MDBX_cmp_func)(const MDBX_val *a, const MDBX_val *b);
/* Environment Flags */
/* no environment directory */
/**** THE FILES ****************************************************************
* At the file system level, the environment corresponds to a pair of files.
* */
/* The name of the lock file in the DB environment */
#define MDBX_LOCKNAME "/mdbx.lck"
/* The name of the data file in the DB environment */
#define MDBX_DATANAME "/mdbx.dat"
/* The suffix of the lock file when MDBX_NOSUBDIR is used */
#define MDBX_LOCK_SUFFIX "-lck"
/**** Environment Flags *******************************************************/
/* MDBX_NOSUBDIR = no environment directory.
*
* - with MDBX_NOSUBDIR = in a filesystem we have the pair of MDBX-files which
* names derived from given pathname by appending predefined suffixes.
*
* - without MDBX_NOSUBDIR = in a filesystem we have the MDBX-directory with
* given pathname, within that a pair of MDBX-files with predefined names. */
#define MDBX_NOSUBDIR 0x4000u
/* don't fsync after commit */
#define MDBX_NOSYNC 0x10000u
/* read only */
/* MDBX_RDONLY = read only mode.
* - with MDBX_RDONLY = open environment in read-only mode.
*
* - without MDBX_RDONLY = open environment in read-write mode*/
#define MDBX_RDONLY 0x20000u
/* don't fsync metapage after commit */
#define MDBX_NOMETASYNC 0x40000u
/* MDBX_EXCLUSIVE = open DB in exclusive/monopolistic mode.
*
* - with MDBX_EXCLUSIVE = open environment in exclusive/monopolistic mode
* or return MDBX_BUSY if environment already used by other process.
* The main feature of the exclusive mode is the ability to open the
* environment placed on a network share..
*
* - without MDBX_RDONLY = open environment in cooperative mode,
* i.e. for multi-process access/interaction/cooperation.
* The main requirements of the cooperative mode are:
* 1. data files MUST be placed in the LOCAL file system,
* but NOT on a network share.
* 2. environment MUST be opened only by LOCAL processes,
* but NOT over a network.
* 3. OS kernel (i.e. file system and memory mapping implementation) and
* all processes that open the given environment MUST be running
* in the physically single RAM with cache-coherency. The only
* exception for cache-consistency requirement is Linux on MIPS
* architecture, but this case has not been tested for a long time). */
#define MDBX_EXCLUSIVE 0x400000u
/* use writable mmap */
#define MDBX_WRITEMAP 0x80000u
/* use asynchronous msync when MDBX_WRITEMAP is used */
#define MDBX_MAPASYNC 0x100000u
/* MDBX_NOSYNC = don't sync data to persistent storage (e.g. disk)
* at the end of transaction commit.
*
*/
#define MDBX_NOSYNC 0x10000u
/* don't fsync metapage after commit */
#define MDBX_NOMETASYNC 0x40000u
/* make a steady-sync only on close and explicit env-sync */
#define MDBX_UTTERLY_NOSYNC (MDBX_NOSYNC | MDBX_MAPASYNC)
/* tie reader locktable slots to MDBX_txn objects instead of to threads */
#define MDBX_NOTLS 0x200000u
/* open DB in exclusive/monopolistic mode. */
#define MDBX_EXCLUSIVE 0x400000u
/* don't do readahead */
#define MDBX_NORDAHEAD 0x800000u
/* don't initialize malloc'd memory before writing to datafile */
@ -323,8 +572,6 @@ typedef int(MDBX_cmp_func)(const MDBX_val *a, const MDBX_val *b);
#define MDBX_COALESCE 0x2000000u
/* LIFO policy for reclaiming FreeDB records */
#define MDBX_LIFORECLAIM 0x4000000u
/* make a steady-sync only on close and explicit env-sync */
#define MDBX_UTTERLY_NOSYNC (MDBX_NOSYNC | MDBX_MAPASYNC)
/* debuging option, fill/perturb released pages */
#define MDBX_PAGEPERTURB 0x8000000u
@ -463,7 +710,8 @@ typedef enum MDBX_cursor_op {
#define MDBX_BAD_DBI (-30780)
/* Unexpected problem - txn should abort */
#define MDBX_PROBLEM (-30779)
/* Another write transaction is running */
/* Another write transaction is running or environment is already used while
* opening with MDBX_EXCLUSIVE flag */
#define MDBX_BUSY (-30778)
/* The last defined error code */
#define MDBX_LAST_ERRCODE MDBX_BUSY

32
src/elements/core.c
View File

@ -1418,8 +1418,8 @@ static const char *__mdbx_strerr(int errnum) {
"MDBX_DBS_FULL: Too may DBI (maxdbs reached)",
"MDBX_READERS_FULL: Too many readers (maxreaders reached)",
NULL /* MDBX_TLS_FULL (-30789): unused in MDBX */,
"MDBX_TXN_FULL: Transaction has too many dirty pages - transaction too "
"big",
"MDBX_TXN_FULL: Transaction has too many dirty pages, "
"i.e transaction too big",
"MDBX_CURSOR_FULL: Internal error - cursor stack limit reached",
"MDBX_PAGE_FULL: Internal error - page has no more space",
"MDBX_MAP_RESIZED: Database contents grew beyond environment mapsize",
@ -1430,7 +1430,8 @@ static const char *__mdbx_strerr(int errnum) {
"DUPFIXED size",
"MDBX_BAD_DBI: The specified DBI handle was closed/changed unexpectedly",
"MDBX_PROBLEM: Unexpected problem - txn should abort",
"MDBX_BUSY: Another write transaction is started",
"MDBX_BUSY: Another write transaction is running or "
"environment is already used while opening with MDBX_EXCLUSIVE flag",
};
if (errnum >= MDBX_KEYEXIST && errnum <= MDBX_LAST_ERRCODE) {
@ -1861,10 +1862,10 @@ static int mdbx_page_befree(MDBX_cursor *mc, MDBX_page *mp) {
/* Loosen or free a single page.
*
* Saves single pages to a list for future reuse
* in this same txn. It has been pulled from the freeDB
* in this same txn. It has been pulled from the GC
* and already resides on the dirty list, but has been
* deleted. Use these pages first before pulling again
* from the freeDB.
* from the GC.
*
* If the page wasn't dirtied in this txn, just add it
* to this txn's free list. */
@ -2529,7 +2530,7 @@ bailout:
*
* If there are free pages available from older transactions, they
* are re-used first. Otherwise allocate a new page at mt_next_pgno.
* Do not modify the freedB, just merge freeDB records into me_reclaimed_pglist
* Do not modify the freedB, just merge GC records into me_reclaimed_pglist
* and move me_last_reclaimed to say which records were consumed. Only this
* function can create me_reclaimed_pglist and move
* me_last_reclaimed/mt_next_pgno.
@ -2559,7 +2560,7 @@ static int mdbx_page_alloc(MDBX_cursor *mc, unsigned num, MDBX_page **mp,
if (likely(flags & MDBX_ALLOC_GC)) {
flags |= env->me_flags & (MDBX_COALESCE | MDBX_LIFORECLAIM);
if (unlikely(mc->mc_flags & C_RECLAIMING)) {
/* If mc is updating the freeDB, then the befree-list cannot play
/* If mc is updating the GC, then the befree-list cannot play
* catch-up with itself by growing while trying to save it. */
flags &=
~(MDBX_ALLOC_GC | MDBX_ALLOC_KICK | MDBX_COALESCE | MDBX_LIFORECLAIM);
@ -2822,7 +2823,7 @@ static int mdbx_page_alloc(MDBX_cursor *mc, unsigned num, MDBX_page **mp,
#endif /* MDBX_PNL sort-order */
}
/* Use new pages from the map when nothing suitable in the freeDB */
/* Use new pages from the map when nothing suitable in the GC */
repg_pos = 0;
pgno = txn->mt_next_pgno;
rc = MDBX_MAP_FULL;
@ -3978,7 +3979,7 @@ static __inline int mdbx_backlog_extragap(MDBX_env *env) {
/* LY: Prepare a backlog of pages to modify FreeDB itself,
* while reclaiming is prohibited. It should be enough to prevent search
* in mdbx_page_alloc() during a deleting, when freeDB tree is unbalanced. */
* in mdbx_page_alloc() during a deleting, when GC tree is unbalanced. */
static int mdbx_prep_backlog(MDBX_txn *txn, MDBX_cursor *mc) {
/* LY: extra page(s) for b-tree rebalancing */
const int extra =
@ -4190,7 +4191,7 @@ retry:
head_gc_id = MDBX_PNL_LAST(txn->mt_lifo_reclaimed);
}
} else {
/* If using records from freeDB which we have not yet deleted,
/* If using records from GC which we have not yet deleted,
* now delete them and any we reserved for me_reclaimed_pglist. */
while (cleaned_gc_id < env->me_last_reclaimed) {
rc = mdbx_cursor_first(&mc, &key, NULL);
@ -4356,14 +4357,14 @@ retry:
// handle befree-list - store ones into singe gc-record
if (befree_stored < MDBX_PNL_SIZE(txn->mt_befree_pages)) {
if (unlikely(!befree_stored)) {
/* Make sure last page of freeDB is touched and on befree-list */
/* Make sure last page of GC is touched and on befree-list */
mc.mc_flags &= ~C_RECLAIMING;
rc = mdbx_page_search(&mc, NULL, MDBX_PS_LAST | MDBX_PS_MODIFY);
mc.mc_flags |= C_RECLAIMING;
if (unlikely(rc != MDBX_SUCCESS) && rc != MDBX_NOTFOUND)
goto bailout;
}
/* Write to last page of freeDB */
/* Write to last page of GC */
key.iov_len = sizeof(txn->mt_txnid);
key.iov_base = &txn->mt_txnid;
do {
@ -11973,7 +11974,7 @@ static int __cold mdbx_env_compact(MDBX_env *env, MDBX_txn *read_txn,
meta->mp_meta.mm_dbs[MAIN_DBI].md_flags =
read_txn->mt_dbs[MAIN_DBI].md_flags;
} else {
/* Count free pages + freeDB pages. Subtract from last_pg
/* Count free pages + GC pages. Subtract from last_pg
* to find the new last_pg, which also becomes the new root. */
pgno_t freecount = 0;
MDBX_cursor mc;
@ -14708,6 +14709,8 @@ int mdbx_set_attr(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data,
}
//----------------------------------------------------------------------------
/* *INDENT-OFF* */
/* clang-format off */
__dll_export
#ifdef __attribute_used__
@ -14778,3 +14781,6 @@ LIBMDBX_API __attribute__((__weak__)) const char *__asan_default_options() {
"abort_on_error=1";
}
#endif /* __SANITIZE_ADDRESS__ */
/* *INDENT-ON* */
/* clang-format on */

3
src/elements/internals.h
View File

@ -238,6 +238,9 @@ extern LIBMDBX_API const char *const mdbx_sourcery_anchor;
/* Number of DBs in metapage (free and main) - also hardcoded elsewhere */
#define CORE_DBS 2
#define MAX_DBI (INT16_MAX - CORE_DBS)
#if MAX_DBI != MDBX_MAX_DBI
#error "Opps, MAX_DBI != MDBX_MAX_DBI"
#endif
/* Number of meta pages - also hardcoded elsewhere */
#define NUM_METAS 3