NAME¶
lmdb.h - Lightning memory-mapped database library.
SYNOPSIS¶
#include <sys/types.h>
Data Structures¶
struct
MDB_val
Generic structure used for passing keys and data in and out of the database.
struct
MDB_stat
Statistics for a database in the environment. struct
MDB_envinfo
Information about the environment.
Macros¶
#define
MDB_VERSION_MAJOR 0
#define
MDB_VERSION_MINOR 9
#define
MDB_VERSION_PATCH 14
#define
MDB_VERINT(a, b, c) (((a) << 24) | ((b) << 16) | (c))
#define
MDB_VERSION_FULL
MDB_VERINT(
MDB_VERSION_MAJOR,
MDB_VERSION_MINOR,
MDB_VERSION_PATCH)
#define
MDB_VERSION_DATE 'September 20, 2014'
#define
MDB_VERSTR(a, b, c, d) 'LMDB ' #a '.' #b '.' #c ': (' d ')'
#define
MDB_VERFOO(a, b, c, d)
MDB_VERSTR(a,b,c,d)
#define
MDB_VERSION_STRING
MDB_VERFOO(
MDB_VERSION_MAJOR,
MDB_VERSION_MINOR,
MDB_VERSION_PATCH,
MDB_VERSION_DATE)
#define
MDB_FIXEDMAP 0x01
#define
MDB_NOSUBDIR 0x4000
#define
MDB_NOSYNC 0x10000
#define
MDB_RDONLY 0x20000
#define
MDB_NOMETASYNC 0x40000
#define
MDB_WRITEMAP 0x80000
#define
MDB_MAPASYNC 0x100000
#define
MDB_NOTLS 0x200000
#define
MDB_NOLOCK 0x400000
#define
MDB_NORDAHEAD 0x800000
#define
MDB_NOMEMINIT 0x1000000
#define
MDB_REVERSEKEY 0x02
#define
MDB_DUPSORT 0x04
#define
MDB_INTEGERKEY 0x08
#define
MDB_DUPFIXED 0x10
#define
MDB_INTEGERDUP 0x20
#define
MDB_REVERSEDUP 0x40
#define
MDB_CREATE 0x40000
#define
MDB_NOOVERWRITE 0x10
#define
MDB_NODUPDATA 0x20
#define
MDB_CURRENT 0x40
#define
MDB_RESERVE 0x10000
#define
MDB_APPEND 0x20000
#define
MDB_APPENDDUP 0x40000
#define
MDB_MULTIPLE 0x80000
#define
MDB_CP_COMPACT 0x01
#define
MDB_SUCCESS 0
#define
MDB_KEYEXIST (-30799)
#define
MDB_NOTFOUND (-30798)
#define
MDB_PAGE_NOTFOUND (-30797)
#define
MDB_CORRUPTED (-30796)
#define
MDB_PANIC (-30795)
#define
MDB_VERSION_MISMATCH (-30794)
#define
MDB_INVALID (-30793)
#define
MDB_MAP_FULL (-30792)
#define
MDB_DBS_FULL (-30791)
#define
MDB_READERS_FULL (-30790)
#define
MDB_TLS_FULL (-30789)
#define
MDB_TXN_FULL (-30788)
#define
MDB_CURSOR_FULL (-30787)
#define
MDB_PAGE_FULL (-30786)
#define
MDB_MAP_RESIZED (-30785)
#define
MDB_INCOMPATIBLE (-30784)
#define
MDB_BAD_RSLOT (-30783)
#define
MDB_BAD_TXN (-30782)
#define
MDB_BAD_VALSIZE (-30781)
#define
MDB_BAD_DBI (-30780)
#define
MDB_LAST_ERRCODE MDB_BAD_DBI
#define
mdb_open(txn, name, flags, dbi)
mdb_dbi_open(txn,name,flags,dbi)
#define
mdb_close(env, dbi)
mdb_dbi_close(env,dbi)
Typedefs¶
typedef mode_t
mdb_mode_t
typedef int
mdb_filehandle_t
typedef unsigned int
MDB_dbi
A handle for an individual database in the DB environment. typedef int(
MDB_cmp_func )(const
MDB_val *a, const
MDB_val *b)
A callback function used to compare two keys in a database. typedef
void(
MDB_rel_func )(
MDB_val *item, void *oldptr, void *newptr,
void *relctx)
A callback function used to relocate a position-dependent data item in a
fixed-address database. typedef void
MDB_assert_func
(
MDB_env *env, const char *msg)
A callback function for most LMDB assert() failures, called before printing
the message and aborting. typedef int(
MDB_msg_func )(const char
*msg, void *ctx)
A callback function used to print a message from the library.
Enumerations¶
enum
MDB_cursor_op {
MDB_FIRST,
MDB_FIRST_DUP,
MDB_GET_BOTH,
MDB_GET_BOTH_RANGE,
MDB_GET_CURRENT,
MDB_GET_MULTIPLE,
MDB_LAST,
MDB_LAST_DUP,
MDB_NEXT,
MDB_NEXT_DUP,
MDB_NEXT_MULTIPLE,
MDB_NEXT_NODUP,
MDB_PREV,
MDB_PREV_DUP,
MDB_PREV_NODUP,
MDB_SET,
MDB_SET_KEY,
MDB_SET_RANGE }
Cursor Get operations.
Functions¶
char *
mdb_version (int *major, int *minor, int *patch)
Return the LMDB library version information. char *
mdb_strerror
(int err)
Return a string describing a given error code. int
mdb_env_create
(
MDB_env **env)
Create an LMDB environment handle. int
mdb_env_open
(
MDB_env *env, const char *path, unsigned int flags,
mdb_mode_t
mode)
Open an environment handle. int
mdb_env_copy (
MDB_env
*env, const char *path)
Copy an LMDB environment to the specified path. int
mdb_env_copyfd (
MDB_env *env,
mdb_filehandle_t fd)
Copy an LMDB environment to the specified file descriptor. int
mdb_env_copy2 (
MDB_env *env, const char *path, unsigned int
flags)
Copy an LMDB environment to the specified path, with options. int
mdb_env_copyfd2 (
MDB_env *env,
mdb_filehandle_t fd,
unsigned int flags)
Copy an LMDB environment to the specified file descriptor, with options.
int
mdb_env_stat (
MDB_env *env,
MDB_stat *stat)
Return statistics about the LMDB environment. int
mdb_env_info
(
MDB_env *env,
MDB_envinfo *stat)
Return information about the LMDB environment. int
mdb_env_sync
(
MDB_env *env, int force)
Flush the data buffers to disk. void
mdb_env_close
(
MDB_env *env)
Close the environment and release the memory map. int
mdb_env_set_flags (
MDB_env *env, unsigned int flags, int onoff)
Set environment flags. int
mdb_env_get_flags (
MDB_env
*env, unsigned int *flags)
Get environment flags. int
mdb_env_get_path (
MDB_env *env,
const char **path)
Return the path that was used in mdb_env_open().
int
mdb_env_get_fd (
MDB_env *env,
mdb_filehandle_t *fd)
Return the filedescriptor for the given environment. int
mdb_env_set_mapsize (
MDB_env *env, size_t size)
Set the size of the memory map to use for this environment. int
mdb_env_set_maxreaders (
MDB_env *env, unsigned int readers)
Set the maximum number of threads/reader slots for the environment. int
mdb_env_get_maxreaders (
MDB_env *env, unsigned int *readers)
Get the maximum number of threads/reader slots for the environment. int
mdb_env_set_maxdbs (
MDB_env *env,
MDB_dbi dbs)
Set the maximum number of named databases for the environment. int
mdb_env_get_maxkeysize (
MDB_env *env)
Get the maximum size of keys and MDB_DUPSORT data we can write.
int
mdb_env_set_userctx (
MDB_env *env, void *ctx)
Set application information associated with the MDB_env.
void *
mdb_env_get_userctx (
MDB_env *env)
Get the application information associated with the MDB_env.
int
mdb_env_set_assert (
MDB_env *env,
MDB_assert_func *func)
int
mdb_txn_begin (
MDB_env *env,
MDB_txn *parent, unsigned
int flags,
MDB_txn **txn)
Create a transaction for use with the environment. MDB_env *
mdb_txn_env (
MDB_txn *txn)
Returns the transaction's MDB_env. int
mdb_txn_commit (
MDB_txn *txn)
Commit all the operations of a transaction into the database. void
mdb_txn_abort (
MDB_txn *txn)
Abandon all the operations of the transaction instead of saving them.
void
mdb_txn_reset (
MDB_txn *txn)
Reset a read-only transaction. int
mdb_txn_renew (
MDB_txn
*txn)
Renew a read-only transaction. int
mdb_dbi_open (
MDB_txn
*txn, const char *name, unsigned int flags,
MDB_dbi *dbi)
Open a database in the environment. int
mdb_stat (
MDB_txn
*txn,
MDB_dbi dbi,
MDB_stat *stat)
Retrieve statistics for a database. int
mdb_dbi_flags
(
MDB_txn *txn,
MDB_dbi dbi, unsigned int *flags)
Retrieve the DB flags for a database handle. void
mdb_dbi_close
(
MDB_env *env,
MDB_dbi dbi)
Close a database handle. Normally unnecessary. Use with care: int
mdb_drop (
MDB_txn *txn,
MDB_dbi dbi, int del)
Empty or delete+close a database. int
mdb_set_compare
(
MDB_txn *txn,
MDB_dbi dbi,
MDB_cmp_func *cmp)
Set a custom key comparison function for a database. int
mdb_set_dupsort (
MDB_txn *txn,
MDB_dbi dbi,
MDB_cmp_func *cmp)
Set a custom data comparison function for a MDB_DUPSORT
database. int
mdb_set_relfunc (
MDB_txn *txn,
MDB_dbi dbi,
MDB_rel_func *rel)
Set a relocation function for a MDB_FIXEDMAP database.
int
mdb_set_relctx (
MDB_txn *txn,
MDB_dbi
dbi, void *ctx)
Set a context pointer for a MDB_FIXEDMAP database's relocation
function. int
mdb_get (
MDB_txn *txn,
MDB_dbi
dbi,
MDB_val *key,
MDB_val *data)
Get items from a database. int
mdb_put (
MDB_txn *txn,
MDB_dbi dbi,
MDB_val *key,
MDB_val *data, unsigned int
flags)
Store items into a database. int
mdb_del (
MDB_txn *txn,
MDB_dbi dbi,
MDB_val *key,
MDB_val *data)
Delete items from a database. int
mdb_cursor_open (
MDB_txn
*txn,
MDB_dbi dbi,
MDB_cursor **cursor)
Create a cursor handle. void
mdb_cursor_close (
MDB_cursor
*cursor)
Close a cursor handle. int
mdb_cursor_renew (
MDB_txn *txn,
MDB_cursor *cursor)
Renew a cursor handle. MDB_txn *
mdb_cursor_txn
(
MDB_cursor *cursor)
Return the cursor's transaction handle. MDB_dbi
mdb_cursor_dbi (
MDB_cursor *cursor)
Return the cursor's database handle. int
mdb_cursor_get
(
MDB_cursor *cursor,
MDB_val *key,
MDB_val *data,
MDB_cursor_op op)
Retrieve by cursor. int
mdb_cursor_put (
MDB_cursor
*cursor,
MDB_val *key,
MDB_val *data, unsigned int flags)
Store by cursor. int
mdb_cursor_del (
MDB_cursor *cursor,
unsigned int flags)
Delete current key/data pair. int
mdb_cursor_count
(
MDB_cursor *cursor, size_t *countp)
Return count of duplicates for current key. int
mdb_cmp
(
MDB_txn *txn,
MDB_dbi dbi, const
MDB_val *a, const
MDB_val *b)
Compare two data items according to a particular database. int
mdb_dcmp (
MDB_txn *txn,
MDB_dbi dbi, const
MDB_val *a, const
MDB_val *b)
Compare two data items according to a particular database. int
mdb_reader_list (
MDB_env *env,
MDB_msg_func *func, void
*ctx)
Dump the entries in the reader lock table. int
mdb_reader_check
(
MDB_env *env, int *dead)
Check for stale entries in the reader lock table.
Detailed Description¶
Lightning memory-mapped database library.
Typedef Documentation¶
typedef mode_t mdb_mode_t¶
Unix permissions for creating files, or dummy definition for Windows
typedef int mdb_filehandle_t¶
An abstraction for a file handle. On POSIX systems file handles are small
integers. On Windows they're opaque pointers.
Author¶
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