diff options
Diffstat (limited to 'innobase/include/trx0sys.h')
| -rw-r--r-- | innobase/include/trx0sys.h | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/innobase/include/trx0sys.h b/innobase/include/trx0sys.h index d0506dd65b7..e26f7e19850 100644 --- a/innobase/include/trx0sys.h +++ b/innobase/include/trx0sys.h @@ -27,6 +27,23 @@ Created 3/26/1996 Heikki Tuuri /* The transaction system */ extern trx_sys_t* trx_sys; +/* Doublewrite system */ +extern trx_doublewrite_t* trx_doublewrite; + +/******************************************************************** +Creates the doublewrite buffer at a database start. The header of the +doublewrite buffer is placed on the trx system header page. */ + +void +trx_sys_create_doublewrite_buf(void); +/*================================*/ +/******************************************************************** +At a database startup uses a possible doublewrite buffer to restore +half-written pages in the data files. */ + +void +trx_sys_doublewrite_restore_corrupt_pages(void); +/*===========================================*/ /******************************************************************* Checks if a page address is the trx sys header page. */ UNIV_INLINE @@ -235,6 +252,59 @@ therefore 256 */ segment specification slots */ /*-------------------------------------------------------------*/ +/* The offset of the doublewrite buffer header on the trx system header page */ +#define TRX_SYS_DOUBLEWRITE (UNIV_PAGE_SIZE - 200) +/*-------------------------------------------------------------*/ +#define TRX_SYS_DOUBLEWRITE_FSEG 0 /* fseg header of the fseg + containing the doublewrite + buffer */ +#define TRX_SYS_DOUBLEWRITE_MAGIC FSEG_HEADER_SIZE + /* 4-byte magic number which + shows if we already have + created the doublewrite + buffer */ +#define TRX_SYS_DOUBLEWRITE_BLOCK1 (4 + FSEG_HEADER_SIZE) + /* page number of the + first page in the first + sequence of 64 + (= FSP_EXTENT_SIZE) consecutive + pages in the doublewrite + buffer */ +#define TRX_SYS_DOUBLEWRITE_BLOCK2 (8 + FSEG_HEADER_SIZE) + /* page number of the + first page in the second + sequence of 64 consecutive + pages in the doublewrite + buffer */ +#define TRX_SYS_DOUBLEWRITE_REPEAT 12 /* we repeat the above 3 + numbers so that if the trx + sys header is half-written + to disk, we still may be able + to recover the information */ +/*-------------------------------------------------------------*/ +#define TRX_SYS_DOUBLEWRITE_MAGIC_N 536853855 + +#define TRX_SYS_DOUBLEWRITE_BLOCK_SIZE FSP_EXTENT_SIZE + +/* Doublewrite control struct */ +struct trx_doublewrite_struct{ + mutex_t mutex; /* mutex protecting the first_free field and + write_buf */ + ulint block1; /* the page number of the first + doublewrite block (64 pages) */ + ulint block2; /* page number of the second block */ + ulint first_free; /* first free position in write_buf measured + in units of UNIV_PAGE_SIZE */ + byte* write_buf; /* write buffer used in writing to the + doublewrite buffer, aligned to an + address divisible by UNIV_PAGE_SIZE + (which is required by Windows aio) */ + byte* write_buf_unaligned; /* pointer to write_buf, but unaligned */ + buf_block_t** + buf_block_arr; /* array to store pointers to the buffer + blocks which have been cached to write_buf */ +}; + /* The transaction system central memory data structure; protected by the kernel mutex */ struct trx_sys_struct{ |