/* LICENSE AND COPYRUSTING ***************************************************** * * Copyright 2015-2017 Leonid Yuriev * 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 * . * * --- * * 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 * . * * --- * * Portions Copyright (c) 2009, 2010 Martin Hedenfalk * * 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 - the author of `btree.c` code, * which was used for begin development of LMDB. */ #pragma once #ifndef LIBMDBX_H #define LIBMDBX_H /* IMPENDING CHANGES WARNING *************************************************** * * Now MDBX is under active development and until November 2017 is expected a * big change both of API and database format. Unfortunately those update will * lead to loss of compatibility with previous versions. * * The aim of this revolution in providing a clearer robust API and adding new * features, including the database properties. */ /*--------------------------------------------------------------------------*/ #ifdef _MSC_VER #pragma warning(push, 1) #pragma warning(disable : 4548) /* expression before comma has no effect; \ expected expression with side - effect */ #pragma warning(disable : 4530) /* C++ exception handler used, but unwind \ * semantics are not enabled. Specify /EHsc */ #pragma warning(disable : 4577) /* 'noexcept' used with no exception handling \ * mode specified; termination on exception is \ * not guaranteed. Specify /EHsc */ #endif /* _MSC_VER (warnings) */ #include #include #include #if defined(_WIN32) || defined(_WIN64) #include #include #ifndef __mode_t_defined typedef unsigned short mode_t; #endif typedef HANDLE mdbx_filehandle_t; typedef DWORD mdbx_pid_t; typedef DWORD mdbx_tid_t; #define MDBX_ENODATA ERROR_HANDLE_EOF #define MDBX_EINVAL ERROR_INVALID_PARAMETER #define MDBX_EACCESS ERROR_ACCESS_DENIED #define MDBX_ENOMEM ERROR_OUTOFMEMORY #define MDBX_EROFS ERROR_FILE_READ_ONLY #define MDBX_ENOSYS ERROR_NOT_SUPPORTED #define MDBX_EIO ERROR_WRITE_FAULT #define MDBX_EPERM ERROR_INVALID_FUNCTION #define MDBX_EINTR ERROR_CANCELLED #else #include /* for error codes */ #include /* for pthread_t */ #include /* for pid_t */ #include /* for truct iovec */ #define HAVE_STRUCT_IOVEC 1 typedef int mdbx_filehandle_t; typedef pid_t mdbx_pid_t; typedef pthread_t mdbx_tid_t; #define MDBX_ENODATA ENODATA #define MDBX_EINVAL EINVAL #define MDBX_EACCESS EACCES #define MDBX_ENOMEM ENOMEM #define MDBX_EROFS EROFS #define MDBX_ENOSYS ENOSYS #define MDBX_EIO EIO #define MDBX_EPERM EPERM #define MDBX_EINTR EINTR #endif #ifdef _MSC_VER #pragma warning(pop) #endif /*--------------------------------------------------------------------------*/ #ifndef __has_attribute #define __has_attribute(x) (0) #endif #ifndef __dll_export #if defined(_WIN32) || defined(__CYGWIN__) #if defined(__GNUC__) || __has_attribute(dllexport) #define __dll_export __attribute__((dllexport)) #elif defined(_MSC_VER) #define __dll_export __declspec(dllexport) #else #define __dll_export #endif #elif defined(__GNUC__) || __has_attribute(visibility) #define __dll_export __attribute__((visibility("default"))) #else #define __dll_export #endif #endif /* __dll_export */ #ifndef __dll_import #if defined(_WIN32) || defined(__CYGWIN__) #if defined(__GNUC__) || __has_attribute(dllimport) #define __dll_import __attribute__((dllimport)) #elif defined(_MSC_VER) #define __dll_import __declspec(dllimport) #else #define __dll_import #endif #else #define __dll_import #endif #endif /* __dll_import */ /*--------------------------------------------------------------------------*/ #define MDBX_VERSION_MAJOR 0 #define MDBX_VERSION_MINOR 0 #if defined(LIBMDBX_EXPORTS) #define LIBMDBX_API __dll_export #elif defined(LIBMDBX_IMPORTS) #define LIBMDBX_API __dll_import #else #define LIBMDBX_API #endif /* LIBMDBX_API */ #ifdef __cplusplus extern "C" { #endif typedef struct mdbx_version_info { uint8_t major; uint8_t minor; uint16_t release; uint32_t revision; struct { const char *datetime; const char *tree; const char *commit; const char *describe; } git; } mdbx_version_info; typedef struct mdbx_build_info { const char *datetime; const char *target; const char *options; const char *compiler; const char *flags; } mdbx_build_info; extern LIBMDBX_API const mdbx_version_info mdbx_version; extern LIBMDBX_API const mdbx_build_info mdbx_build; /* 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" /* Opaque structure for a database environment. * * A DB environment supports multiple databases, all residing in the same * shared-memory map. */ typedef struct MDBX_env MDBX_env; /* Opaque structure for a transaction handle. * * All database operations require a transaction handle. Transactions may be * read-only or read-write. */ typedef struct MDBX_txn MDBX_txn; /* A handle for an individual database in the DB environment. */ typedef uint32_t MDBX_dbi; /* Opaque structure for navigating through a database */ typedef struct MDBX_cursor MDBX_cursor; /* Generic structure used for passing keys and data in and out * of the database. * * Values returned from the database are valid only until a subsequent * update operation, or the end of the transaction. Do not modify or * free them, they commonly point into the database itself. * * Key sizes must be between 1 and mdbx_env_get_maxkeysize() inclusive. * The same applies to data sizes in databases with the MDBX_DUPSORT flag. * Other data items can in theory be from 0 to 0xffffffff bytes long. */ #ifndef HAVE_STRUCT_IOVEC struct iovec { void *iov_base; size_t iov_len; }; #define HAVE_STRUCT_IOVEC #endif /* HAVE_STRUCT_IOVEC */ typedef struct iovec MDBX_val; /* The maximum size of a data item. * MDBX only store a 32 bit value for node sizes. */ #define MDBX_MAXDATASIZE INT32_MAX /* 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 */ #define MDBX_NOSUBDIR 0x4000u /* don't fsync after commit */ #define MDBX_NOSYNC 0x10000u /* read only */ #define MDBX_RDONLY 0x20000u /* don't fsync metapage after commit */ #define MDBX_NOMETASYNC 0x40000u /* use writable mmap */ #define MDBX_WRITEMAP 0x80000u /* use asynchronous msync when MDBX_WRITEMAP is used */ #define MDBX_MAPASYNC 0x100000u /* tie reader locktable slots to MDBX_txn objects instead of to threads */ #define MDBX_NOTLS 0x200000u /* don't do any locking, caller must manage their own locks * WARNING: libmdbx don't support this mode. */ #define MDBX_NOLOCK__UNSUPPORTED 0x400000u /* don't do readahead */ #define MDBX_NORDAHEAD 0x800000u /* don't initialize malloc'd memory before writing to datafile */ #define MDBX_NOMEMINIT 0x1000000u /* aim to coalesce FreeDB records */ #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 /* Database Flags */ /* use reverse string keys */ #define MDBX_REVERSEKEY 0x02u /* use sorted duplicates */ #define MDBX_DUPSORT 0x04u /* numeric keys in native byte order, either uint32_t or uint64_t. * The keys must all be of the same size. */ #define MDBX_INTEGERKEY 0x08u /* with MDBX_DUPSORT, sorted dup items have fixed size */ #define MDBX_DUPFIXED 0x10u /* with MDBX_DUPSORT, dups are MDBX_INTEGERKEY-style integers */ #define MDBX_INTEGERDUP 0x20u /* with MDBX_DUPSORT, use reverse string dups */ #define MDBX_REVERSEDUP 0x40u /* create DB if not already existing */ #define MDBX_CREATE 0x40000u /* Write Flags */ /* For put: Don't write if the key already exists. */ #define MDBX_NOOVERWRITE 0x10u /* Only for MDBX_DUPSORT * For put: don't write if the key and data pair already exist. * For mdbx_cursor_del: remove all duplicate data items. */ #define MDBX_NODUPDATA 0x20u /* For mdbx_cursor_put: overwrite the current key/data pair * MDBX allows this flag for mdbx_put() for explicit overwrite/update without * insertion. */ #define MDBX_CURRENT 0x40u /* For put: Just reserve space for data, don't copy it. Return a * pointer to the reserved space. */ #define MDBX_RESERVE 0x10000u /* Data is being appended, don't split full pages. */ #define MDBX_APPEND 0x20000u /* Duplicate data is being appended, don't split full pages. */ #define MDBX_APPENDDUP 0x40000u /* Store multiple data items in one call. Only for MDBX_DUPFIXED. */ #define MDBX_MULTIPLE 0x80000u /* Transaction Flags */ /* Do not block when starting a write transaction */ #define MDBX_TRYTXN 0x10000000u /* Copy Flags */ /* Compacting copy: Omit free space from copy, and renumber all * pages sequentially. */ #define MDBX_CP_COMPACT 1u /* Cursor Get operations. * * This is the set of all operations for retrieving data * using a cursor. */ typedef enum MDBX_cursor_op { MDBX_FIRST, /* Position at first key/data item */ MDBX_FIRST_DUP, /* MDBX_DUPSORT-only: Position at first data item * of current key. */ MDBX_GET_BOTH, /* MDBX_DUPSORT-only: Position at key/data pair. */ MDBX_GET_BOTH_RANGE, /* MDBX_DUPSORT-only: position at key, nearest data. */ MDBX_GET_CURRENT, /* Return key/data at current cursor position */ MDBX_GET_MULTIPLE, /* MDBX_DUPFIXED-only: Return key and up to a page of * duplicate data items from current cursor position. * Move cursor to prepare for MDBX_NEXT_MULTIPLE.*/ MDBX_LAST, /* Position at last key/data item */ MDBX_LAST_DUP, /* MDBX_DUPSORT-only: Position at last data item * of current key. */ MDBX_NEXT, /* Position at next data item */ MDBX_NEXT_DUP, /* MDBX_DUPSORT-only: Position at next data item * of current key. */ MDBX_NEXT_MULTIPLE, /* MDBX_DUPFIXED-only: Return key and up to a page of * duplicate data items from next cursor position. * Move cursor to prepare for MDBX_NEXT_MULTIPLE. */ MDBX_NEXT_NODUP, /* Position at first data item of next key */ MDBX_PREV, /* Position at previous data item */ MDBX_PREV_DUP, /* MDBX_DUPSORT-only: Position at previous data item * of current key. */ MDBX_PREV_NODUP, /* Position at last data item of previous key */ MDBX_SET, /* Position at specified key */ MDBX_SET_KEY, /* Position at specified key, return both key and data */ MDBX_SET_RANGE, /* Position at first key greater than or equal to * specified key. */ MDBX_PREV_MULTIPLE /* MDBX_DUPFIXED-only: Position at previous page and * return key and up to a page of duplicate data items. */ } MDBX_cursor_op; /* Return Codes * BerkeleyDB uses -30800 to -30999, we'll go under them */ /* Successful result */ #define MDBX_SUCCESS 0 #define MDBX_RESULT_FALSE MDBX_SUCCESS #define MDBX_RESULT_TRUE (-1) /* key/data pair already exists */ #define MDBX_KEYEXIST (-30799) /* key/data pair not found (EOF) */ #define MDBX_NOTFOUND (-30798) /* Requested page not found - this usually indicates corruption */ #define MDBX_PAGE_NOTFOUND (-30797) /* Located page was wrong type */ #define MDBX_CORRUPTED (-30796) /* Update of meta page failed or environment had fatal error */ #define MDBX_PANIC (-30795) /* DB file version mismatch with libmdbx */ #define MDBX_VERSION_MISMATCH (-30794) /* File is not a valid MDBX file */ #define MDBX_INVALID (-30793) /* Environment mapsize reached */ #define MDBX_MAP_FULL (-30792) /* Environment maxdbs reached */ #define MDBX_DBS_FULL (-30791) /* Environment maxreaders reached */ #define MDBX_READERS_FULL (-30790) /* Txn has too many dirty pages */ #define MDBX_TXN_FULL (-30788) /* Cursor stack too deep - internal error */ #define MDBX_CURSOR_FULL (-30787) /* Page has not enough space - internal error */ #define MDBX_PAGE_FULL (-30786) /* Database contents grew beyond environment mapsize */ #define MDBX_MAP_RESIZED (-30785) /* Operation and DB incompatible, or DB type changed. This can mean: * - The operation expects an MDBX_DUPSORT / MDBX_DUPFIXED database. * - Opening a named DB when the unnamed DB has MDBX_DUPSORT/MDBX_INTEGERKEY. * - Accessing a data record as a database, or vice versa. * - The database was dropped and recreated with different flags. */ #define MDBX_INCOMPATIBLE (-30784) /* Invalid reuse of reader locktable slot */ #define MDBX_BAD_RSLOT (-30783) /* Transaction must abort, has a child, or is invalid */ #define MDBX_BAD_TXN (-30782) /* Unsupported size of key/DB name/data, or wrong DUPFIXED size */ #define MDBX_BAD_VALSIZE (-30781) /* The specified DBI was changed unexpectedly */ #define MDBX_BAD_DBI (-30780) /* Unexpected problem - txn should abort */ #define MDBX_PROBLEM (-30779) /* Unexpected problem - txn should abort */ #define MDBX_BUSY (-30778) /* The last defined error code */ #define MDBX_LAST_ERRCODE MDBX_BUSY /* The mdbx_put() or mdbx_replace() was called for key, that has more that one associated value. */ #define MDBX_EMULTIVAL (-30421) /* Bad signature of a runtime object(s), this can mean: * - memory corruption or double-free; * - ABI version mismatch (rare case); */ #define MDBX_EBADSIGN (-30420) /* Database should be recovered, but this could NOT be done automatically * right now (e.g. in readonly mode and so forth). */ #define MDBX_WANNA_RECOVERY (-30419) /* The given key value is mismatched to the current cursor position, * when mdbx_cursor_put() called with MDBX_CURRENT option. */ #define MDBX_EKEYMISMATCH (-30418) /* Database is too large for current system, * e.g. could NOT be mapped into RAM. */ #define MDBX_TOO_LARGE (-30417) /* A thread has attempted to use a not owned object, * e.g. a transaction that started by another thread. */ #define MDBX_THREAD_MISMATCH (-30416) /* Statistics for a database in the environment */ typedef struct MDBX_stat { uint32_t ms_psize; /* Size of a database page. * This is currently the same for all databases. */ uint32_t ms_depth; /* Depth (height) of the B-tree */ uint64_t ms_branch_pages; /* Number of internal (non-leaf) pages */ uint64_t ms_leaf_pages; /* Number of leaf pages */ uint64_t ms_overflow_pages; /* Number of overflow pages */ uint64_t ms_entries; /* Number of data items */ } MDBX_stat; /* Information about the environment */ typedef struct MDBX_envinfo { struct { uint64_t lower; /* lower limit for datafile size */ uint64_t upper; /* upper limit for datafile size */ uint64_t current; /* current datafile size */ uint64_t shrink; /* shrink theshold for datafile */ uint64_t grow; /* growth step for datafile */ } mi_geo; uint64_t mi_mapsize; /* Size of the data memory map */ uint64_t mi_last_pgno; /* ID of the last used page */ uint64_t mi_recent_txnid; /* ID of the last committed transaction */ uint64_t mi_latter_reader_txnid; /* ID of the last reader transaction */ uint64_t mi_meta0_txnid, mi_meta0_sign; uint64_t mi_meta1_txnid, mi_meta1_sign; uint64_t mi_meta2_txnid, mi_meta2_sign; uint32_t mi_maxreaders; /* max reader slots in the environment */ uint32_t mi_numreaders; /* max reader slots used in the environment */ uint32_t mi_dxb_pagesize; /* database pagesize */ uint32_t mi_sys_pagesize; /* system pagesize */ } MDBX_envinfo; /* Return a string describing a given error code. * * This function is a superset of the ANSI C X3.159-1989 (ANSI C) strerror(3) * function. If the error code is greater than or equal to 0, then the string * returned by the system function strerror(3) is returned. If the error code * is less than 0, an error string corresponding to the MDBX library error is * returned. See errors for a list of MDBX-specific error codes. * * [in] err The error code * * Returns "error message" The description of the error */ LIBMDBX_API const char *mdbx_strerror(int errnum); LIBMDBX_API const char *mdbx_strerror_r(int errnum, char *buf, size_t buflen); /* Create an MDBX environment handle. * * This function allocates memory for a MDBX_env structure. To release * the allocated memory and discard the handle, call mdbx_env_close(). * Before the handle may be used, it must be opened using mdbx_env_open(). * Various other options may also need to be set before opening the handle, * e.g. mdbx_env_set_mapsize(), mdbx_env_set_maxreaders(), * mdbx_env_set_maxdbs(), depending on usage requirements. * * [out] env The address where the new handle will be stored * * Returns A non-zero error value on failure and 0 on success. */ LIBMDBX_API int mdbx_env_create(MDBX_env **penv); /* Open an environment handle. * * If this function fails, mdbx_env_close() must be called to discard * the MDBX_env handle. * * [in] env An environment handle returned by mdbx_env_create() * [in] path The directory in which the database files reside. * This directory must already exist and be writable. * [in] flags Special options for this environment. This parameter * must be set to 0 or by bitwise OR'ing together one * or more of the values described here. * * Flags set by mdbx_env_set_flags() are also used: * - MDBX_NOSUBDIR * By default, MDBX creates its environment in a directory whose * pathname is given in path, and creates its data and lock files * under that directory. With this option, path is used as-is for * the database main data file. The database lock file is the path * with "-lock" appended. * * - MDBX_RDONLY * Open the environment in read-only mode. No write operations will * be allowed. MDBX will still modify the lock file - except on * read-only filesystems, where MDBX does not use locks. * * - MDBX_WRITEMAP * Use a writeable memory map unless MDBX_RDONLY is set. This uses fewer * mallocs but loses protection from application bugs like wild pointer * writes and other bad updates into the database. * This may be slightly faster for DBs that fit entirely in RAM, * but is slower for DBs larger than RAM. * Incompatible with nested transactions. * Do not mix processes with and without MDBX_WRITEMAP on the same * environment. This can defeat durability (mdbx_env_sync etc). * * - MDBX_NOMETASYNC * Flush system buffers to disk only once per transaction, omit the * metadata flush. Defer that until the system flushes files to disk, * or next non-MDBX_RDONLY commit or mdbx_env_sync(). This optimization * maintains database integrity, but a system crash may undo the last * committed transaction. I.e. it preserves the ACI (atomicity, * consistency, isolation) but not D (durability) database property. * This flag may be changed at any time using mdbx_env_set_flags(). * * - MDBX_NOSYNC * Don't flush system buffers to disk when committing a transaction. * This optimization means a system crash can corrupt the database or * lose the last transactions if buffers are not yet flushed to disk. * The risk is governed by how often the system flushes dirty buffers * to disk and how often mdbx_env_sync() is called. However, if the * filesystem preserves write order and the MDBX_WRITEMAP and/or * MDBX_LIFORECLAIM flags are not used, transactions exhibit ACI * (atomicity, consistency, isolation) properties and only lose D * (durability). I.e. database integrity is maintained, but a system * crash may undo the final transactions. * * Note that (MDBX_NOSYNC | MDBX_WRITEMAP) leaves the system with no * hint for when to write transactions to disk. * Therefore the (MDBX_MAPASYNC | MDBX_WRITEMAP) may be preferable. * This flag may be changed at any time using mdbx_env_set_flags(). * * - MDBX_UTTERLY_NOSYNC (internally MDBX_NOSYNC | MDBX_MAPASYNC) * FIXME: TODO * * - MDBX_MAPASYNC * When using MDBX_WRITEMAP, use asynchronous flushes to disk. As with * MDBX_NOSYNC, a system crash can then corrupt the database or lose * the last transactions. Calling mdbx_env_sync() ensures on-disk * database integrity until next commit. This flag may be changed at * any time using mdbx_env_set_flags(). * * - MDBX_NOTLS * Don't use Thread-Local Storage. Tie reader locktable slots to * MDBX_txn objects instead of to threads. I.e. mdbx_txn_reset() keeps * the slot reseved for the MDBX_txn object. A thread may use parallel * read-only transactions. A read-only transaction may span threads if * the user synchronizes its use. Applications that multiplex many * user threads over individual OS threads need this option. Such an * application must also serialize the write transactions in an OS * thread, since MDBX's write locking is unaware of the user threads. * * - MDBX_NOLOCK (don't supported by MDBX) * Don't do any locking. If concurrent access is anticipated, the * caller must manage all concurrency itself. For proper operation * the caller must enforce single-writer semantics, and must ensure * that no readers are using old transactions while a writer is * active. The simplest approach is to use an exclusive lock so that * no readers may be active at all when a writer begins. * * - MDBX_NORDAHEAD * Turn off readahead. Most operating systems perform readahead on * read requests by default. This option turns it off if the OS * supports it. Turning it off may help random read performance * when the DB is larger than RAM and system RAM is full. * * - MDBX_NOMEMINIT * Don't initialize malloc'd memory before writing to unused spaces * in the data file. By default, memory for pages written to the data * file is obtained using malloc. While these pages may be reused in * subsequent transactions, freshly malloc'd pages will be initialized * to zeroes before use. This avoids persisting leftover data from other * code (that used the heap and subsequently freed the memory) into the * data file. Note that many other system libraries may allocate and free * memory from the heap for arbitrary uses. E.g., stdio may use the heap * for file I/O buffers. This initialization step has a modest performance * cost so some applications may want to disable it using this flag. This * option can be a problem for applications which handle sensitive data * like passwords, and it makes memory checkers like Valgrind noisy. This * flag is not needed with MDBX_WRITEMAP, which writes directly to the * mmap instead of using malloc for pages. The initialization is also * skipped if MDBX_RESERVE is used; the caller is expected to overwrite * all of the memory that was reserved in that case. This flag may be * changed at any time using mdbx_env_set_flags(). * * - MDBX_COALESCE * Aim to coalesce records while reclaiming FreeDB. This flag may be * changed at any time using mdbx_env_set_flags(). * FIXME: TODO * * - MDBX_LIFORECLAIM * LIFO policy for reclaiming FreeDB records. This significantly reduce * write IPOs in case MDBX_NOSYNC with periodically checkpoints. * FIXME: TODO * * [in] mode The UNIX permissions to set on created files. * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_VERSION_MISMATCH - the version of the MDBX library doesn't match the * version that created the database environment. * - MDBX_INVALID - the environment file headers are corrupted. * - MDBX_ENOENT - the directory specified by the path parameter * doesn't exist. * - MDBX_EACCES - the user didn't have permission to access * the environment files. * - MDBX_EAGAIN - the environment was locked by another process. */ LIBMDBX_API int mdbx_env_open(MDBX_env *env, const char *path, unsigned flags, mode_t mode); LIBMDBX_API int mdbx_env_open_ex(MDBX_env *env, const char *path, unsigned flags, mode_t mode, int *exclusive); /* Copy an MDBX environment to the specified path, with options. * * This function may be used to make a backup of an existing environment. * No lockfile is created, since it gets recreated at need. * NOTE: This call can trigger significant file size growth if run in * parallel with write transactions, because it employs a read-only * transaction. See long-lived transactions under "Caveats" section. * * [in] env An environment handle returned by mdbx_env_create(). It must * have already been opened successfully. * [in] path The directory in which the copy will reside. This directory * must already exist and be writable but must otherwise be empty. * [in] flags Special options for this operation. This parameter must be set * to 0 or by bitwise OR'ing together one or more of the values * described here: * * - MDBX_CP_COMPACT * Perform compaction while copying: omit free pages and sequentially * renumber all pages in output. This option consumes little bit more * CPU for processing, but may running quickly than the default, on * account skipping free pages. * * NOTE: Currently it fails if the environment has suffered a page leak. * * Returns A non-zero error value on failure and 0 on success. */ LIBMDBX_API int mdbx_env_copy(MDBX_env *env, const char *path, unsigned flags); /* Copy an MDBX environment to the specified file descriptor, * with options. * * This function may be used to make a backup of an existing environment. * No lockfile is created, since it gets recreated at need. See * mdbx_env_copy() for further details. * * NOTE: This call can trigger significant file size growth if run in * parallel with write transactions, because it employs a read-only * transaction. See long-lived transactions under "Caveats" section. * * [in] env An environment handle returned by mdbx_env_create(). It must * have already been opened successfully. * [in] fd The filedescriptor to write the copy to. It must have already * been opened for Write access. * [in] flags Special options for this operation. See mdbx_env_copy() for * options. * * Returns A non-zero error value on failure and 0 on success. */ LIBMDBX_API int mdbx_env_copy2fd(MDBX_env *env, mdbx_filehandle_t fd, unsigned flags); /* Return statistics about the MDBX environment. * * [in] env An environment handle returned by mdbx_env_create() * [out] stat The address of an MDBX_stat structure where the statistics * will be copied */ LIBMDBX_API int mdbx_env_stat(MDBX_env *env, MDBX_stat *stat, size_t bytes); /* Return information about the MDBX environment. * * [in] env An environment handle returned by mdbx_env_create() * [out] stat The address of an MDBX_envinfo structure * where the information will be copied */ LIBMDBX_API int mdbx_env_info(MDBX_env *env, MDBX_envinfo *info, size_t bytes); /* Flush the data buffers to disk. * * Data is always written to disk when mdbx_txn_commit() is called, * but the operating system may keep it buffered. MDBX always flushes * the OS buffers upon commit as well, unless the environment was * opened with MDBX_NOSYNC or in part MDBX_NOMETASYNC. This call is * not valid if the environment was opened with MDBX_RDONLY. * * [in] env An environment handle returned by mdbx_env_create() * [in] force If non-zero, force a synchronous flush. Otherwise if the * environment has the MDBX_NOSYNC flag set the flushes will be * omitted, and with MDBX_MAPASYNC they will be asynchronous. * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_EACCES - the environment is read-only. * - MDBX_EINVAL - an invalid parameter was specified. * - MDBX_EIO - an error occurred during synchronization. */ LIBMDBX_API int mdbx_env_sync(MDBX_env *env, int force); /* Close the environment and release the memory map. * * Only a single thread may call this function. All transactions, databases, * and cursors must already be closed before calling this function. Attempts * to use any such handles after calling this function will cause a SIGSEGV. * The environment handle will be freed and must not be used again after this * call. * * [in] env An environment handle returned by mdbx_env_create() * [in] dont_sync A dont'sync flag, if non-zero the last checkpoint (meta-page * update) will be kept "as is" and may be still "weak" in the * NOSYNC/MAPASYNC modes. Such "weak" checkpoint will be * ignored on opening next time, and transactions since the * last non-weak checkpoint (meta-page update) will rolledback * for consistency guarantee. */ LIBMDBX_API void mdbx_env_close(MDBX_env *env); /* Set environment flags. * * This may be used to set some flags in addition to those from * mdbx_env_open(), or to unset these flags. If several threads * change the flags at the same time, the result is undefined. * * [in] env An environment handle returned by mdbx_env_create() * [in] flags The flags to change, bitwise OR'ed together * [in] onoff A non-zero value sets the flags, zero clears them. * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_EINVAL - an invalid parameter was specified. */ LIBMDBX_API int mdbx_env_set_flags(MDBX_env *env, unsigned flags, int onoff); /* Get environment flags. * * [in] env An environment handle returned by mdbx_env_create() * [out] flags The address of an integer to store the flags * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_EINVAL - an invalid parameter was specified. */ LIBMDBX_API int mdbx_env_get_flags(MDBX_env *env, unsigned *flags); /* Return the path that was used in mdbx_env_open(). * * [in] env An environment handle returned by mdbx_env_create() * [out] path Address of a string pointer to contain the path. * This is the actual string in the environment, not a copy. * It should not be altered in any way. * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_EINVAL - an invalid parameter was specified. */ LIBMDBX_API int mdbx_env_get_path(MDBX_env *env, const char **path); /* Return the file descriptor for the given environment. * * NOTE: All MDBX file descriptors have FD_CLOEXEC and * could't be used after exec() and or fork(). * * [in] env An environment handle returned by mdbx_env_create() * [out] fd Address of a int to contain the descriptor. * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_EINVAL - an invalid parameter was specified. */ LIBMDBX_API int mdbx_env_get_fd(MDBX_env *env, mdbx_filehandle_t *fd); /* Set the size of the memory map to use for this environment. * * The size should be a multiple of the OS page size. The default is * 10485760 bytes. The size of the memory map is also the maximum size * of the database. The value should be chosen as large as possible, * to accommodate future growth of the database. * This function should be called after mdbx_env_create() and before * mdbx_env_open(). It may be called at later times if no transactions * are active in this process. Note that the library does not check for * this condition, the caller must ensure it explicitly. * * The new size takes effect immediately for the current process but * will not be persisted to any others until a write transaction has been * committed by the current process. Also, only mapsize increases are * persisted into the environment. * * If the mapsize is increased by another process, and data has grown * beyond the range of the current mapsize, mdbx_txn_begin() will * return MDBX_MAP_RESIZED. This function may be called with a size * of zero to adopt the new size. * * Any attempt to set a size smaller than the space already consumed by the * environment will be silently changed to the current size of the used space. * * [in] env An environment handle returned by mdbx_env_create() * [in] size The size in bytes * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_EINVAL - an invalid parameter was specified, * or the environment has an active write transaction. */ LIBMDBX_API int mdbx_env_set_mapsize(MDBX_env *env, size_t size); LIBMDBX_API int mdbx_env_set_geometry(MDBX_env *env, intptr_t size_lower, intptr_t size_now, intptr_t size_upper, intptr_t growth_step, intptr_t shrink_threshold, intptr_t pagesize); /* Set the maximum number of threads/reader slots for the environment. * * This defines the number of slots in the lock table that is used to track * readers in the the environment. The default is 61. * Starting a read-only transaction normally ties a lock table slot to the * current thread until the environment closes or the thread exits. If * MDBX_NOTLS is in use, mdbx_txn_begin() instead ties the slot to the * MDBX_txn object until it or the MDBX_env object is destroyed. * This function may only be called after mdbx_env_create() and before * mdbx_env_open(). * * [in] env An environment handle returned by mdbx_env_create() * [in] readers The maximum number of reader lock table slots * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_EINVAL - an invalid parameter was specified, * or the environment is already open. */ LIBMDBX_API int mdbx_env_set_maxreaders(MDBX_env *env, unsigned readers); /* Get the maximum number of threads/reader slots for the environment. * * [in] env An environment handle returned by mdbx_env_create() * [out] readers Address of an integer to store the number of readers * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_EINVAL - an invalid parameter was specified. */ LIBMDBX_API int mdbx_env_get_maxreaders(MDBX_env *env, unsigned *readers); /* Set the maximum number of named databases for the environment. * * This function is only needed if multiple databases will be used in the * environment. Simpler applications that use the environment as a single * unnamed database can ignore this option. * This function may only be called after mdbx_env_create() and before * mdbx_env_open(). * * Currently a moderate number of slots are cheap but a huge number gets * expensive: 7-120 words per transaction, and every mdbx_dbi_open() * does a linear search of the opened slots. * * [in] env An environment handle returned by mdbx_env_create() * [in] dbs The maximum number of databases * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_EINVAL - an invalid parameter was specified, * or the environment is already open. */ LIBMDBX_API int mdbx_env_set_maxdbs(MDBX_env *env, MDBX_dbi dbs); /* Get the maximum size of keys and MDBX_DUPSORT data we can write. * * [in] env An environment handle returned by mdbx_env_create() * * Returns The maximum size of a key we can write. */ LIBMDBX_API int mdbx_env_get_maxkeysize(MDBX_env *env); LIBMDBX_API int mdbx_get_maxkeysize(size_t pagesize); /* Set application information associated with the MDBX_env. * * [in] env An environment handle returned by mdbx_env_create() * [in] ctx An arbitrary pointer for whatever the application needs. * * Returns A non-zero error value on failure and 0 on success. */ LIBMDBX_API int mdbx_env_set_userctx(MDBX_env *env, void *ctx); /* Get the application information associated with the MDBX_env. * * [in] env An environment handle returned by mdbx_env_create() * Returns The pointer set by mdbx_env_set_userctx(). */ LIBMDBX_API void *mdbx_env_get_userctx(MDBX_env *env); /* A callback function for most MDBX assert() failures, * called before printing the message and aborting. * * [in] env An environment handle returned by mdbx_env_create(). * [in] msg The assertion message, not including newline. */ typedef void MDBX_assert_func(const MDBX_env *env, const char *msg, const char *function, unsigned line); /* Set or reset the assert() callback of the environment. * * Disabled if libmdbx is buillt with MDBX_DEBUG=0. * NOTE: This hack should become obsolete as mdbx's error handling matures. * * [in] env An environment handle returned by mdbx_env_create(). * [in] func An MDBX_assert_func function, or 0. * * Returns A non-zero error value on failure and 0 on success. */ LIBMDBX_API int mdbx_env_set_assert(MDBX_env *env, MDBX_assert_func *func); /* Create a transaction for use with the environment. * * The transaction handle may be discarded using mdbx_txn_abort() * or mdbx_txn_commit(). * NOTE: A transaction and its cursors must only be used by a single * thread, and a thread may only have a single transaction at a time. * If MDBX_NOTLS is in use, this does not apply to read-only transactions. * NOTE: Cursors may not span transactions. * * [in] env An environment handle returned by mdbx_env_create() * [in] parent If this parameter is non-NULL, the new transaction will be * a nested transaction, with the transaction indicated by parent * as its parent. Transactions may be nested to any level. * A parent transaction and its cursors may not issue any other * operations than mdbx_txn_commit and mdbx_txn_abort while it * has active child transactions. * [in] flags Special options for this transaction. This parameter * must be set to 0 or by bitwise OR'ing together one or more * of the values described here. * * - MDBX_RDONLY * This transaction will not perform any write operations. * * - MDBX_TRYTXN * Do not block when starting a write transaction * * [out] txn Address where the new MDBX_txn handle will be stored * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_PANIC - a fatal error occurred earlier and the environment * must be shut down. * - MDBX_MAP_RESIZED - another process wrote data beyond this MDBX_env's * mapsize and this environment's map must be resized * as well. See mdbx_env_set_mapsize(). * - MDBX_READERS_FULL - a read-only transaction was requested and the reader * lock table is full. See mdbx_env_set_maxreaders(). * - MDBX_ENOMEM - out of memory. * - MDBX_BUSY - a write transaction is already started. */ LIBMDBX_API int mdbx_txn_begin(MDBX_env *env, MDBX_txn *parent, unsigned flags, MDBX_txn **txn); /* Returns the transaction's MDBX_env * * [in] txn A transaction handle returned by mdbx_txn_begin() */ LIBMDBX_API MDBX_env *mdbx_txn_env(MDBX_txn *txn); /* Return the transaction's ID. * * This returns the identifier associated with this transaction. For a * read-only transaction, this corresponds to the snapshot being read; * concurrent readers will frequently have the same transaction ID. * * [in] txn A transaction handle returned by mdbx_txn_begin() * * Returns A transaction ID, valid if input is an active transaction. */ LIBMDBX_API uint64_t mdbx_txn_id(MDBX_txn *txn); /* Commit all the operations of a transaction into the database. * * The transaction handle is freed. It and its cursors must not be used * again after this call, except with mdbx_cursor_renew(). * * A cursor must be closed explicitly always, before * or after its transaction ends. It can be reused with * mdbx_cursor_renew() before finally closing it. * * [in] txn A transaction handle returned by mdbx_txn_begin() * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_EINVAL - an invalid parameter was specified. * - MDBX_ENOSPC - no more disk space. * - MDBX_EIO - a low-level I/O error occurred while writing. * - MDBX_ENOMEM - out of memory. */ LIBMDBX_API int mdbx_txn_commit(MDBX_txn *txn); /* Abandon all the operations of the transaction instead of saving them. * * The transaction handle is freed. It and its cursors must not be used * again after this call, except with mdbx_cursor_renew(). * * A cursor must be closed explicitly always, before or after its transaction * ends. It can be reused with mdbx_cursor_renew() before finally closing it. * * [in] txn A transaction handle returned by mdbx_txn_begin(). */ LIBMDBX_API int mdbx_txn_abort(MDBX_txn *txn); /* Reset a read-only transaction. * * Abort the transaction like mdbx_txn_abort(), but keep the transaction * handle. Therefore mdbx_txn_renew() may reuse the handle. This saves * allocation overhead if the process will start a new read-only transaction * soon, and also locking overhead if MDBX_NOTLS is in use. The reader table * lock is released, but the table slot stays tied to its thread or * MDBX_txn. Use mdbx_txn_abort() to discard a reset handle, and to free * its lock table slot if MDBX_NOTLS is in use. * * Cursors opened within the transaction must not be used * again after this call, except with mdbx_cursor_renew(). * * Reader locks generally don't interfere with writers, but they keep old * versions of database pages allocated. Thus they prevent the old pages * from being reused when writers commit new data, and so under heavy load * the database size may grow much more rapidly than otherwise. * * [in] txn A transaction handle returned by mdbx_txn_begin() */ LIBMDBX_API int mdbx_txn_reset(MDBX_txn *txn); /* Renew a read-only transaction. * * This acquires a new reader lock for a transaction handle that had been * released by mdbx_txn_reset(). It must be called before a reset transaction * may be used again. * * [in] txn A transaction handle returned by mdbx_txn_begin() * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_PANIC - a fatal error occurred earlier and the environment * must be shut down. * - MDBX_EINVAL - an invalid parameter was specified. */ LIBMDBX_API int mdbx_txn_renew(MDBX_txn *txn); /* Open a table in the environment. * * A table handle denotes the name and parameters of a table, independently * of whether such a table exists. The table handle may be discarded by * calling mdbx_dbi_close(). The old table handle is returned if the table * was already open. The handle may only be closed once. * * The table handle will be private to the current transaction until * the transaction is successfully committed. If the transaction is * aborted the handle will be closed automatically. * After a successful commit the handle will reside in the shared * environment, and may be used by other transactions. * * This function must not be called from multiple concurrent * transactions in the same process. A transaction that uses * this function must finish (either commit or abort) before * any other transaction in the process may use this function. * * To use named table (with name != NULL), mdbx_env_set_maxdbs() * must be called before opening the environment. Table names are * keys in the internal unnamed table, and may be read but not written. * * [in] txn transaction handle returned by mdbx_txn_begin() * [in] name The name of the table to open. If only a single * table is needed in the environment, this value may be NULL. * [in] flags Special options for this table. This parameter must be set * to 0 or by bitwise OR'ing together one or more of the values * described here: * - MDBX_REVERSEKEY * Keys are strings to be compared in reverse order, from the end * of the strings to the beginning. By default, Keys are treated as * strings and compared from beginning to end. * - MDBX_DUPSORT * Duplicate keys may be used in the table. Or, from another point of * view, keys may have multiple data items, stored in sorted order. By * default keys must be unique and may have only a single data item. * - MDBX_INTEGERKEY * Keys are binary integers in native byte order, either uin32_t or * uint64_t, and will be sorted as such. The keys must all be of the * same size. * - MDBX_DUPFIXED * This flag may only be used in combination with MDBX_DUPSORT. This * option tells the library that the data items for this database are * all the same size, which allows further optimizations in storage and * retrieval. When all data items are the same size, the MDBX_GET_MULTIPLE, * MDBX_NEXT_MULTIPLE and MDBX_PREV_MULTIPLE cursor operations may be used * to retrieve multiple items at once. * - MDBX_INTEGERDUP * This option specifies that duplicate data items are binary integers, * similar to MDBX_INTEGERKEY keys. * - MDBX_REVERSEDUP * This option specifies that duplicate data items should be compared as * strings in reverse order (the comparison is performed in the direction * from the last byte to the first). * - MDBX_CREATE * Create the named database if it doesn't exist. This option is not * allowed in a read-only transaction or a read-only environment. * * [out] dbi Address where the new MDBX_dbi handle will be stored * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_NOTFOUND - the specified database doesn't exist in the * environment and MDBX_CREATE was not specified. * - MDBX_DBS_FULL - too many databases have been opened. * See mdbx_env_set_maxdbs(). */ LIBMDBX_API int mdbx_dbi_open_ex(MDBX_txn *txn, const char *name, unsigned flags, MDBX_dbi *dbi, MDBX_cmp_func *keycmp, MDBX_cmp_func *datacmp); LIBMDBX_API int mdbx_dbi_open(MDBX_txn *txn, const char *name, unsigned flags, MDBX_dbi *dbi); /* Retrieve statistics for a database. * * [in] txn A transaction handle returned by mdbx_txn_begin() * [in] dbi A database handle returned by mdbx_dbi_open() * [out] stat The address of an MDBX_stat structure where the statistics * will be copied * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_EINVAL - an invalid parameter was specified. */ LIBMDBX_API int mdbx_dbi_stat(MDBX_txn *txn, MDBX_dbi dbi, MDBX_stat *stat, size_t bytes); /* Retrieve the DB flags for a database handle. * * [in] txn A transaction handle returned by mdbx_txn_begin() * [in] dbi A database handle returned by mdbx_dbi_open() * [out] flags Address where the flags will be returned. * [out] state Address where the state will be returned. * * Returns A non-zero error value on failure and 0 on success. */ #define MDBX_TBL_DIRTY 0x01 /* DB was written in this txn */ #define MDBX_TBL_STALE 0x02 /* Named-DB record is older than txnID */ #define MDBX_TBL_NEW 0x04 /* Named-DB handle opened in this txn */ LIBMDBX_API int mdbx_dbi_flags_ex(MDBX_txn *txn, MDBX_dbi dbi, unsigned *flags, unsigned *state); LIBMDBX_API int mdbx_dbi_flags(MDBX_txn *txn, MDBX_dbi dbi, unsigned *flags); /* Close a database handle. Normally unnecessary. * * Use with care: * FIXME: This call is not mutex protected. Handles should only be closed by * a single thread, and only if no other threads are going to reference * the database handle or one of its cursors any further. Do not close * a handle if an existing transaction has modified its database. * Doing so can cause misbehavior from database corruption to errors * like MDBX_BAD_VALSIZE (since the DB name is gone). * * Closing a database handle is not necessary, but lets mdbx_dbi_open() * reuse the handle value. Usually it's better to set a bigger * mdbx_env_set_maxdbs(), unless that value would be large. * * [in] env An environment handle returned by mdbx_env_create() * [in] dbi A database handle returned by mdbx_dbi_open() */ LIBMDBX_API int mdbx_dbi_close(MDBX_env *env, MDBX_dbi dbi); /* Empty or delete+close a database. * * See mdbx_dbi_close() for restrictions about closing the DB handle. * * [in] txn A transaction handle returned by mdbx_txn_begin() * [in] dbi A database handle returned by mdbx_dbi_open() * [in] del 0 to empty the DB, 1 to delete it from the environment * and close the DB handle. * * Returns A non-zero error value on failure and 0 on success. */ LIBMDBX_API int mdbx_drop(MDBX_txn *txn, MDBX_dbi dbi, int del); /* Get items from a database. * * This function retrieves key/data pairs from the database. The address * and length of the data associated with the specified key are returned * in the structure to which data refers. * If the database supports duplicate keys (MDBX_DUPSORT) then the * first data item for the key will be returned. Retrieval of other * items requires the use of mdbx_cursor_get(). * * NOTE: The memory pointed to by the returned values is owned by the * database. The caller need not dispose of the memory, and may not * modify it in any way. For values returned in a read-only transaction * any modification attempts will cause a SIGSEGV. * * NOTE: Values returned from the database are valid only until a * subsequent update operation, or the end of the transaction. * * [in] txn A transaction handle returned by mdbx_txn_begin() * [in] dbi A database handle returned by mdbx_dbi_open() * [in] key The key to search for in the database * [in,out] data The data corresponding to the key * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_NOTFOUND - the key was not in the database. * - MDBX_EINVAL - an invalid parameter was specified. */ LIBMDBX_API int mdbx_get(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data); /* Store items into a database. * * This function stores key/data pairs in the database. The default behavior * is to enter the new key/data pair, replacing any previously existing key * if duplicates are disallowed, or adding a duplicate data item if * duplicates are allowed (MDBX_DUPSORT). * * [in] txn A transaction handle returned by mdbx_txn_begin() * [in] dbi A database handle returned by mdbx_dbi_open() * [in] key The key to store in the database * [in,out] data The data to store * [in] flags Special options for this operation. This parameter must be * set to 0 or by bitwise OR'ing together one or more of the * values described here. * * - MDBX_NODUPDATA * Enter the new key/data pair only if it does not already appear * in the database. This flag may only be specified if the database * was opened with MDBX_DUPSORT. The function will return MDBX_KEYEXIST * if the key/data pair already appears in the database. * * - MDBX_NOOVERWRITE * Enter the new key/data pair only if the key does not already appear * in the database. The function will return MDBX_KEYEXIST if the key * already appears in the database, even if the database supports * duplicates (MDBX_DUPSORT). The data parameter will be set to point * to the existing item. * * - MDBX_CURRENT * Update an single existing entry, but not add new ones. The function * will return MDBX_NOTFOUND if the given key not exist in the database. * Or the MDBX_EMULTIVAL in case duplicates for the given key. * * - MDBX_RESERVE * Reserve space for data of the given size, but don't copy the given * data. Instead, return a pointer to the reserved space, which the * caller can fill in later - before the next update operation or the * transaction ends. This saves an extra memcpy if the data is being * generated later. MDBX does nothing else with this memory, the caller * is expected to modify all of the space requested. This flag must not * be specified if the database was opened with MDBX_DUPSORT. * * - MDBX_APPEND * Append the given key/data pair to the end of the database. This option * allows fast bulk loading when keys are already known to be in the * correct order. Loading unsorted keys with this flag will cause * a MDBX_EKEYMISMATCH error. * * - MDBX_APPENDDUP * As above, but for sorted dup data. * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_KEYEXIST * - MDBX_MAP_FULL - the database is full, see mdbx_env_set_mapsize(). * - MDBX_TXN_FULL - the transaction has too many dirty pages. * - MDBX_EACCES - an attempt was made to write in a read-only transaction. * - MDBX_EINVAL - an invalid parameter was specified. */ LIBMDBX_API int mdbx_put(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data, unsigned flags); /* Delete items from a database. * * This function removes key/data pairs from the database. * * The data parameter is NOT ignored regardless the database does * support sorted duplicate data items or not. If the data parameter * is non-NULL only the matching data item will be deleted. * * This function will return MDBX_NOTFOUND if the specified key/data * pair is not in the database. * * [in] txn A transaction handle returned by mdbx_txn_begin() * [in] dbi A database handle returned by mdbx_dbi_open() * [in] key The key to delete from the database * [in] data The data to delete * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_EACCES - an attempt was made to write in a read-only transaction. * - MDBX_EINVAL - an invalid parameter was specified. */ LIBMDBX_API int mdbx_del(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data); /* Create a cursor handle. * * A cursor is associated with a specific transaction and database. * A cursor cannot be used when its database handle is closed. Nor * when its transaction has ended, except with mdbx_cursor_renew(). * It can be discarded with mdbx_cursor_close(). * * A cursor must be closed explicitly always, before * or after its transaction ends. It can be reused with * mdbx_cursor_renew() before finally closing it. * * [in] txn A transaction handle returned by mdbx_txn_begin() * [in] dbi A database handle returned by mdbx_dbi_open() * [out] cursor Address where the new MDBX_cursor handle will be stored * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_EINVAL - an invalid parameter was specified. */ LIBMDBX_API int mdbx_cursor_open(MDBX_txn *txn, MDBX_dbi dbi, MDBX_cursor **cursor); /* Close a cursor handle. * * The cursor handle will be freed and must not be used again after this call. * Its transaction must still be live if it is a write-transaction. * * [in] cursor A cursor handle returned by mdbx_cursor_open() */ LIBMDBX_API void mdbx_cursor_close(MDBX_cursor *cursor); /* Renew a cursor handle. * * A cursor is associated with a specific transaction and database. * Cursors that are only used in read-only transactions may be re-used, * to avoid unnecessary malloc/free overhead. The cursor may be associated * with a new read-only transaction, and referencing the same database handle * as it was created with. * * This may be done whether the previous transaction is live or dead. * [in] txn A transaction handle returned by mdbx_txn_begin() * [in] cursor A cursor handle returned by mdbx_cursor_open() * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_EINVAL - an invalid parameter was specified. */ LIBMDBX_API int mdbx_cursor_renew(MDBX_txn *txn, MDBX_cursor *cursor); /* Return the cursor's transaction handle. * * [in] cursor A cursor handle returned by mdbx_cursor_open() */ LIBMDBX_API MDBX_txn *mdbx_cursor_txn(MDBX_cursor *cursor); /* Return the cursor's database handle. * * [in] cursor A cursor handle returned by mdbx_cursor_open() */ LIBMDBX_API MDBX_dbi mdbx_cursor_dbi(MDBX_cursor *cursor); /* Retrieve by cursor. * * This function retrieves key/data pairs from the database. The address and * length of the key are returned in the object to which key refers (except * for the case of the MDBX_SET option, in which the key object is unchanged), * and the address and length of the data are returned in the object to which * data refers. See mdbx_get() for restrictions on using the output values. * * [in] cursor A cursor handle returned by mdbx_cursor_open() * [in,out] key The key for a retrieved item * [in,out] data The data of a retrieved item * [in] op A cursor operation MDBX_cursor_op * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_NOTFOUND - no matching key found. * - MDBX_EINVAL - an invalid parameter was specified. */ LIBMDBX_API int mdbx_cursor_get(MDBX_cursor *cursor, MDBX_val *key, MDBX_val *data, MDBX_cursor_op op); /* Store by cursor. * * This function stores key/data pairs into the database. The cursor is * positioned at the new item, or on failure usually near it. * * [in] cursor A cursor handle returned by mdbx_cursor_open() * [in] key The key operated on. * [in] data The data operated on. * [in] flags Options for this operation. This parameter * must be set to 0 or one of the values described here: * * - MDBX_CURRENT * Replace the item at the current cursor position. The key parameter * must still be provided, and must match it, otherwise the function * return MDBX_EKEYMISMATCH. * * NOTE: MDBX unlike LMDB allows you to change the size of the data and * automatically handles reordering for sorted duplicates (MDBX_DUPSORT). * * - MDBX_NODUPDATA * Enter the new key/data pair only if it does not already appear in the * database. This flag may only be specified if the database was opened * with MDBX_DUPSORT. The function will return MDBX_KEYEXIST if the * key/data pair already appears in the database. * * - MDBX_NOOVERWRITE * Enter the new key/data pair only if the key does not already appear * in the database. The function will return MDBX_KEYEXIST if the key * already appears in the database, even if the database supports * duplicates (MDBX_DUPSORT). * * - MDBX_RESERVE * Reserve space for data of the given size, but don't copy the given * data. Instead, return a pointer to the reserved space, which the * caller can fill in later - before the next update operation or the * transaction ends. This saves an extra memcpy if the data is being * generated later. This flag must not be specified if the database * was opened with MDBX_DUPSORT. * * - MDBX_APPEND * Append the given key/data pair to the end of the database. No key * comparisons are performed. This option allows fast bulk loading when * keys are already known to be in the correct order. Loading unsorted * keys with this flag will cause a MDBX_KEYEXIST error. * * - MDBX_APPENDDUP * As above, but for sorted dup data. * * - MDBX_MULTIPLE * Store multiple contiguous data elements in a single request. This flag * may only be specified if the database was opened with MDBX_DUPFIXED. * The data argument must be an array of two MDBX_vals. The iov_len of the * first MDBX_val must be the size of a single data element. The iov_base * of the first MDBX_val must point to the beginning of the array of * contiguous data elements. The iov_len of the second MDBX_val must be * the count of the number of data elements to store. On return this * field will be set to the count of the number of elements actually * written. The iov_base of the second MDBX_val is unused. * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_EKEYMISMATCH * - MDBX_MAP_FULL - the database is full, see mdbx_env_set_mapsize(). * - MDBX_TXN_FULL - the transaction has too many dirty pages. * - MDBX_EACCES - an attempt was made to write in a read-only transaction. * - MDBX_EINVAL - an invalid parameter was specified. */ LIBMDBX_API int mdbx_cursor_put(MDBX_cursor *cursor, MDBX_val *key, MDBX_val *data, unsigned flags); /* Delete current key/data pair * * This function deletes the key/data pair to which the cursor refers. * * [in] cursor A cursor handle returned by mdbx_cursor_open() * [in] flags Options for this operation. This parameter must be set to 0 * or one of the values described here. * * - MDBX_NODUPDATA * Delete all of the data items for the current key. This flag may only * be specified if the database was opened with MDBX_DUPSORT. * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_EACCES - an attempt was made to write in a read-only transaction. * - MDBX_EINVAL - an invalid parameter was specified. */ LIBMDBX_API int mdbx_cursor_del(MDBX_cursor *cursor, unsigned flags); /* Return count of duplicates for current key. * * This call is only valid on databases that support sorted duplicate data * items MDBX_DUPSORT. * * [in] cursor A cursor handle returned by mdbx_cursor_open() * [out] countp Address where the count will be stored * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_EINVAL - cursor is not initialized, or an invalid parameter * was specified. */ LIBMDBX_API int mdbx_cursor_count(MDBX_cursor *cursor, size_t *countp); /* Compare two data items according to a particular database. * * This returns a comparison as if the two data items were keys in the * specified database. * * [in] txn A transaction handle returned by mdbx_txn_begin() * [in] dbi A database handle returned by mdbx_dbi_open() * [in] a The first item to compare * [in] b The second item to compare * * Returns < 0 if a < b, 0 if a == b, > 0 if a > b */ LIBMDBX_API int mdbx_cmp(MDBX_txn *txn, MDBX_dbi dbi, const MDBX_val *a, const MDBX_val *b); /* Compare two data items according to a particular database. * * This returns a comparison as if the two items were data items of * the specified database. The database must have the MDBX_DUPSORT flag. * * [in] txn A transaction handle returned by mdbx_txn_begin() * [in] dbi A database handle returned by mdbx_dbi_open() * [in] a The first item to compare * [in] b The second item to compare * * Returns < 0 if a < b, 0 if a == b, > 0 if a > b */ LIBMDBX_API int mdbx_dcmp(MDBX_txn *txn, MDBX_dbi dbi, const MDBX_val *a, const MDBX_val *b); /* A callback function used to print a message from the library. * * [in] msg The string to be printed. * [in] ctx An arbitrary context pointer for the callback. * * Returns < 0 on failure, >= 0 on success. */ typedef int(MDBX_msg_func)(const char *msg, void *ctx); /* Dump the entries in the reader lock table. * * [in] env An environment handle returned by mdbx_env_create() * [in] func A MDBX_msg_func function * [in] ctx Anything the message function needs * * Returns < 0 on failure, >= 0 on success. */ LIBMDBX_API int mdbx_reader_list(MDBX_env *env, MDBX_msg_func *func, void *ctx); /* Check for stale entries in the reader lock table. * * [in] env An environment handle returned by mdbx_env_create() * [out] dead Number of stale slots that were cleared * * Returns 0 on success, non-zero on failure. */ LIBMDBX_API int mdbx_reader_check(MDBX_env *env, int *dead); LIBMDBX_API char *mdbx_dkey(const MDBX_val *key, char *const buf, const size_t bufsize); LIBMDBX_API int mdbx_env_close_ex(MDBX_env *env, int dont_sync); /* Set threshold to force flush the data buffers to disk, * even of MDBX_NOSYNC, MDBX_NOMETASYNC and MDBX_MAPASYNC flags * in the environment. * * Data is always written to disk when mdbx_txn_commit() is called, * but the operating system may keep it buffered. MDBX always flushes * the OS buffers upon commit as well, unless the environment was * opened with MDBX_NOSYNC or in part MDBX_NOMETASYNC. * * The default is 0, than mean no any threshold checked, and no additional * flush will be made. * * [in] env An environment handle returned by mdbx_env_create() * [in] bytes The size in bytes of summary changes when a synchronous * flush would be made. * * Returns A non-zero error value on failure and 0 on success. */ LIBMDBX_API int mdbx_env_set_syncbytes(MDBX_env *env, size_t bytes); /* Returns a lag of the reading for the given transaction. * * Returns an information for estimate how much given read-only * transaction is lagging relative the to actual head. * * [in] txn A transaction handle returned by mdbx_txn_begin() * [out] percent Percentage of page allocation in the database. * * Returns Number of transactions committed after the given was started for * read, or -1 on failure. */ LIBMDBX_API int mdbx_txn_straggler(MDBX_txn *txn, int *percent); /* A callback function for killing a laggard readers, * but also could waiting ones. Called in case of MDBX_MAP_FULL error. * * [in] env An environment handle returned by mdbx_env_create(). * [in] pid pid of the reader process. * [in] tid thread_id of the reader thread. * [in] txn Transaction number on which stalled. * [in] gap A lag from the last commited txn. * [in] retry A retry number, less that zero for notify end of OOM-loop. * * Returns -1 on failure (reader is not killed), * 0 should wait or retry, * 1 drop reader txn-lock (reading-txn was aborted), * >1 drop reader registration (reader process was killed). */ typedef int(MDBX_oom_func)(MDBX_env *env, int pid, mdbx_tid_t tid, uint64_t txn, unsigned gap, int retry); /* Set the OOM callback. * * Callback will be called only on out-of-pages case for killing * a laggard readers to allowing reclaiming of freeDB. * * [in] env An environment handle returned by mdbx_env_create(). * [in] oomfunc A MDBX_oom_func function or NULL to disable. * * Returns A non-zero error value on failure and 0 on success. */ LIBMDBX_API int mdbx_env_set_oomfunc(MDBX_env *env, MDBX_oom_func *oom_func); /* Get the current oom_func callback. * * Callback will be called only on out-of-pages case for killing * a laggard readers to allowing reclaiming of freeDB. * * [in] env An environment handle returned by mdbx_env_create(). * * Returns A MDBX_oom_func function or NULL if disabled. */ LIBMDBX_API MDBX_oom_func *mdbx_env_get_oomfunc(MDBX_env *env); #define MDBX_DBG_ASSERT 1 #define MDBX_DBG_PRINT 2 #define MDBX_DBG_TRACE 4 #define MDBX_DBG_EXTRA 8 #define MDBX_DBG_AUDIT 16 #define MDBX_DBG_JITTER 32 #define MDBX_DBG_DUMP 64 typedef void MDBX_debug_func(int type, const char *function, int line, const char *msg, va_list args); LIBMDBX_API int mdbx_setup_debug(int flags, MDBX_debug_func *logger); typedef int MDBX_pgvisitor_func(uint64_t pgno, unsigned pgnumber, void *ctx, const char *dbi, const char *type, size_t nentries, size_t payload_bytes, size_t header_bytes, size_t unused_bytes); LIBMDBX_API int mdbx_env_pgwalk(MDBX_txn *txn, MDBX_pgvisitor_func *visitor, void *ctx); typedef struct mdbx_canary { uint64_t x, y, z, v; } mdbx_canary; LIBMDBX_API int mdbx_canary_put(MDBX_txn *txn, const mdbx_canary *canary); LIBMDBX_API int mdbx_canary_get(MDBX_txn *txn, mdbx_canary *canary); /* Returns: * - MDBX_RESULT_TRUE * when no more data available or cursor not positioned; * - MDBX_RESULT_FALSE * when data available; * - Otherwise the error code. */ LIBMDBX_API int mdbx_cursor_eof(MDBX_cursor *mc); /* Returns: MDBX_RESULT_TRUE, MDBX_RESULT_FALSE or Error code. */ LIBMDBX_API int mdbx_cursor_on_first(MDBX_cursor *mc); /* Returns: MDBX_RESULT_TRUE, MDBX_RESULT_FALSE or Error code. */ LIBMDBX_API int mdbx_cursor_on_last(MDBX_cursor *mc); LIBMDBX_API int mdbx_replace(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *new_data, MDBX_val *old_data, unsigned flags); /* Same as mdbx_get(), but: * 1) if values_count is not NULL, then returns the count * of multi-values/duplicates for a given key. * 2) updates the key for pointing to the actual key's data inside DB. */ LIBMDBX_API int mdbx_get_ex(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data, size_t *values_count); LIBMDBX_API int mdbx_is_dirty(const MDBX_txn *txn, const void *ptr); LIBMDBX_API int mdbx_dbi_sequence(MDBX_txn *txn, MDBX_dbi dbi, uint64_t *result, uint64_t increment); /*----------------------------------------------------------------------------*/ /* attribute support functions for Nexenta */ typedef uint_fast64_t mdbx_attr_t; /* Store by cursor with attribute. * * This function stores key/data pairs into the database. The cursor is * positioned at the new item, or on failure usually near it. * * NOTE: Internally based on MDBX_RESERVE feature, * therefore doesn't support MDBX_DUPSORT. * * [in] cursor A cursor handle returned by mdbx_cursor_open() * [in] key The key operated on. * [in] data The data operated on. * [in] attr The attribute. * [in] flags Options for this operation. This parameter must be set to 0 * or one of the values described here: * * - MDBX_CURRENT * Replace the item at the current cursor position. The key parameter * must still be provided, and must match it, otherwise the function * return MDBX_EKEYMISMATCH. * * - MDBX_APPEND * Append the given key/data pair to the end of the database. No key * comparisons are performed. This option allows fast bulk loading when * keys are already known to be in the correct order. Loading unsorted * keys with this flag will cause a MDBX_KEYEXIST error. * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_EKEYMISMATCH * - MDBX_MAP_FULL - the database is full, see mdbx_env_set_mapsize(). * - MDBX_TXN_FULL - the transaction has too many dirty pages. * - MDBX_EACCES - an attempt was made to write in a read-only transaction. * - MDBX_EINVAL - an invalid parameter was specified. */ LIBMDBX_API int mdbx_cursor_put_attr(MDBX_cursor *cursor, MDBX_val *key, MDBX_val *data, mdbx_attr_t attr, unsigned flags); /* Store items and attributes into a database. * * This function stores key/data pairs in the database. The default behavior * is to enter the new key/data pair, replacing any previously existing key * if duplicates are disallowed. * * NOTE: Internally based on MDBX_RESERVE feature, * therefore doesn't support MDBX_DUPSORT. * * [in] txn A transaction handle returned by mdbx_txn_begin(). * [in] dbi A database handle returned by mdbx_dbi_open(). * [in] key The key to store in the database. * [in] attr The attribute to store in the database. * [in,out] data The data to store. * [in] flags Special options for this operation. This parameter must be * set to 0 or by bitwise OR'ing together one or more of the * values described here: * * - MDBX_NOOVERWRITE * Enter the new key/data pair only if the key does not already appear * in the database. The function will return MDBX_KEYEXIST if the key * already appears in the database. The data parameter will be set to * point to the existing item. * * - MDBX_CURRENT * Update an single existing entry, but not add new ones. The function * will return MDBX_NOTFOUND if the given key not exist in the database. * Or the MDBX_EMULTIVAL in case duplicates for the given key. * * - MDBX_APPEND * Append the given key/data pair to the end of the database. This option * allows fast bulk loading when keys are already known to be in the * correct order. Loading unsorted keys with this flag will cause * a MDBX_EKEYMISMATCH error. * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_KEYEXIST * - MDBX_MAP_FULL - the database is full, see mdbx_env_set_mapsize(). * - MDBX_TXN_FULL - the transaction has too many dirty pages. * - MDBX_EACCES - an attempt was made to write in a read-only transaction. * - MDBX_EINVAL - an invalid parameter was specified. */ LIBMDBX_API int mdbx_put_attr(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data, mdbx_attr_t attr, unsigned flags); /* Set items attribute from a database. * * This function stores key/data pairs attribute to the database. * * NOTE: Internally based on MDBX_RESERVE feature, * therefore doesn't support MDBX_DUPSORT. * * [in] txn A transaction handle returned by mdbx_txn_begin(). * [in] dbi A database handle returned by mdbx_dbi_open(). * [in] key The key to search for in the database. * [in] data The data to be stored or NULL to save previous value. * [in] attr The attribute to be stored. * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_NOTFOUND - the key-value pair was not in the database. * - MDBX_EINVAL - an invalid parameter was specified. */ LIBMDBX_API int mdbx_set_attr(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data, mdbx_attr_t attr); /* Get items attribute from a database cursor. * * This function retrieves key/data pairs from the database. The address and * length of the key are returned in the object to which key refers (except * for the case of the MDBX_SET option, in which the key object is unchanged), * and the address and length of the data are returned in the object to which * data refers. See mdbx_get() for restrictions on using the output values. * * [in] cursor A cursor handle returned by mdbx_cursor_open() * [in,out] key The key for a retrieved item * [in,out] data The data of a retrieved item * [in] op A cursor operation MDBX_cursor_op * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_NOTFOUND - no matching key found. * - MDBX_EINVAL - an invalid parameter was specified. */ LIBMDBX_API int mdbx_cursor_get_attr(MDBX_cursor *mc, MDBX_val *key, MDBX_val *data, mdbx_attr_t *attrptr, MDBX_cursor_op op); /* Get items attribute from a database. * * This function retrieves key/data pairs from the database. The address * and length of the data associated with the specified key are returned * in the structure to which data refers. * If the database supports duplicate keys (MDBX_DUPSORT) then the * first data item for the key will be returned. Retrieval of other * items requires the use of mdbx_cursor_get(). * * NOTE: The memory pointed to by the returned values is owned by the * database. The caller need not dispose of the memory, and may not * modify it in any way. For values returned in a read-only transaction * any modification attempts will cause a SIGSEGV. * * NOTE: Values returned from the database are valid only until a * subsequent update operation, or the end of the transaction. * * [in] txn A transaction handle returned by mdbx_txn_begin() * [in] dbi A database handle returned by mdbx_dbi_open() * [in] key The key to search for in the database * [in,out] data The data corresponding to the key * * Returns A non-zero error value on failure and 0 on success, some * possible errors are: * - MDBX_NOTFOUND - the key was not in the database. * - MDBX_EINVAL - an invalid parameter was specified. */ LIBMDBX_API int mdbx_get_attr(MDBX_txn *txn, MDBX_dbi dbi, MDBX_val *key, MDBX_val *data, mdbx_attr_t *attrptr); #ifdef __cplusplus } #endif #endif /* LIBMDBX_H */