Meta page content. More...

Collaboration diagram for MDB_meta:

Public Attributes
uint32_t	mm_magic
	Stamp identifying this as an LMDB file. More...

uint32_t	mm_version
	Version number of this file. More...

void *	mm_address
	address for fixed mapping More...

size_t	mm_mapsize
	size of mmap region More...

MDB_db	mm_dbs [2]
	first is free space, 2nd is main db More...

pgno_t	mm_last_pg
	Last used page in the datafile. More...

volatile txnid_t	mm_txnid
	txnid that committed this page More...

Detailed Description

Meta page content.

A meta page is the start point for accessing a database snapshot. Pages 0-1 are meta pages. Transaction N writes meta page #(N % 2).

Definition at line 1036 of file mdb.c.

Member Data Documentation

◆ mm_address

void* MDB_meta::mm_address

address for fixed mapping

Definition at line 1042 of file mdb.c.

Referenced by mdb_env_copyfd1(), mdb_env_info(), and mdb_env_open2().

◆ mm_dbs

MDB_db MDB_meta::mm_dbs[2]

first is free space, 2nd is main db

Definition at line 1044 of file mdb.c.

Referenced by mdb_env_copyfd1(), mdb_env_init_meta0(), mdb_env_open2(), mdb_env_stat(), mdb_env_write_meta(), and mdb_txn_renew0().

◆ mm_last_pg

pgno_t MDB_meta::mm_last_pg

Last used page in the datafile.

Actually the file may be shorter if the freeDB lists the final pages.

Definition at line 1052 of file mdb.c.

Referenced by mdb_env_copyfd1(), mdb_env_info(), mdb_env_init_meta0(), mdb_env_open2(), mdb_env_set_mapsize(), mdb_env_write_meta(), and mdb_txn_renew0().

◆ mm_magic

uint32_t MDB_meta::mm_magic

Stamp identifying this as an LMDB file.

It must be set to MDB_MAGIC.

Definition at line 1039 of file mdb.c.

Referenced by mdb_env_init_meta0(), and mdb_env_read_header().

◆ mm_mapsize

size_t MDB_meta::mm_mapsize

size of mmap region

Definition at line 1043 of file mdb.c.

Referenced by mdb_env_init_meta0(), mdb_env_open2(), mdb_env_set_mapsize(), and mdb_env_write_meta().

◆ mm_txnid

volatile txnid_t MDB_meta::mm_txnid

txnid that committed this page

Definition at line 1053 of file mdb.c.

Referenced by mdb_env_copyfd1(), mdb_env_info(), mdb_env_open2(), mdb_env_pick_meta(), mdb_env_read_header(), mdb_env_share_locks(), mdb_env_write_meta(), and mdb_txn_renew0().

◆ mm_version

uint32_t MDB_meta::mm_version

Version number of this file.

Must be set to MDB_DATA_VERSION.

Definition at line 1041 of file mdb.c.

Referenced by mdb_env_init_meta0(), mdb_env_open2(), and mdb_env_read_header().

The documentation for this struct was generated from the following file:

src/util/lmdb/mdb.c

Public Attributes