diff options
Diffstat (limited to 'storage/innobase/include/buf0buf.h')
| -rw-r--r-- | storage/innobase/include/buf0buf.h | 70 |
1 files changed, 38 insertions, 32 deletions
diff --git a/storage/innobase/include/buf0buf.h b/storage/innobase/include/buf0buf.h index ae8d0411c12..12aac878614 100644 --- a/storage/innobase/include/buf0buf.h +++ b/storage/innobase/include/buf0buf.h @@ -1,14 +1,14 @@ /* Innobase relational database engine; Copyright (C) 2001 Innobase Oy - + This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License 2 as published by the Free Software Foundation in June 1991. - + This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. - + You should have received a copy of the GNU General Public License 2 along with this program (in file COPYING); if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ @@ -55,14 +55,14 @@ Created 11/5/1995 Heikki Tuuri /* Magic value to use instead of checksums when they are disabled */ #define BUF_NO_CHECKSUM_MAGIC 0xDEADBEEFUL -extern buf_pool_t* buf_pool; /* The buffer pool of the database */ +extern buf_pool_t* buf_pool; /* The buffer pool of the database */ #ifdef UNIV_DEBUG extern ibool buf_debug_prints;/* If this is set TRUE, the program prints info whenever read or flush occurs */ #endif /* UNIV_DEBUG */ extern ulint srv_buf_pool_write_requests; /* variable to count write request - issued */ + issued */ /************************************************************************ Creates the buffer pool. */ @@ -134,7 +134,7 @@ buf_frame_copy( NOTE! The following macros should be used instead of buf_page_get_gen, to improve debugging. Only values RW_S_LATCH and RW_X_LATCH are allowed in LA! */ -#define buf_page_get(SP, OF, LA, MTR) buf_page_get_gen(\ +#define buf_page_get(SP, OF, LA, MTR) buf_page_get_gen(\ SP, OF, LA, NULL,\ BUF_GET, __FILE__, __LINE__, MTR) /****************************************************************** @@ -143,13 +143,13 @@ read the contents of the page unless you know it is safe. Do not modify the contents of the page! We have separated this case, because it is error-prone programming not to set a latch, and it should be used with care. */ -#define buf_page_get_with_no_latch(SP, OF, MTR) buf_page_get_gen(\ +#define buf_page_get_with_no_latch(SP, OF, MTR) buf_page_get_gen(\ SP, OF, RW_NO_LATCH, NULL,\ BUF_GET_NO_LATCH, __FILE__, __LINE__, MTR) /****************************************************************** NOTE! The following macros should be used instead of buf_page_get_gen, to improve debugging. Only values RW_S_LATCH and RW_X_LATCH are allowed as LA! */ -#define buf_page_get_nowait(SP, OF, LA, MTR) buf_page_get_gen(\ +#define buf_page_get_nowait(SP, OF, LA, MTR) buf_page_get_gen(\ SP, OF, LA, NULL,\ BUF_GET_NOWAIT, __FILE__, __LINE__, MTR) /****************************************************************** @@ -266,7 +266,7 @@ the buffer pool. */ void buf_page_make_young( -/*=================*/ +/*================*/ buf_frame_t* frame); /* in: buffer frame of a file page */ /************************************************************************ Returns TRUE if the page can be found in the buffer pool hash table. NOTE @@ -380,7 +380,7 @@ buf_block_modify_clock_inc( /* out: new value */ buf_block_t* block); /* in: block */ /************************************************************************ -Returns the value of the modify clock. The caller must have an s-lock +Returns the value of the modify clock. The caller must have an s-lock or x-lock on the block. */ UNIV_INLINE dulint @@ -396,12 +396,12 @@ on 32-bit and 64-bit architectures. */ ulint buf_calc_page_new_checksum( /*=======================*/ - /* out: checksum */ - byte* page); /* in: buffer page */ + /* out: checksum */ + byte* page); /* in: buffer page */ /************************************************************************ In versions < 4.0.14 and < 4.1.1 there was a bug that the checksum only looked at the first few bytes of the page. This calculates that old -checksum. +checksum. NOTE: we must first store the new formula checksum to FIL_PAGE_SPACE_OR_CHKSUM before calculating and storing this old checksum because this takes that field as an input! */ @@ -409,8 +409,8 @@ because this takes that field as an input! */ ulint buf_calc_page_old_checksum( /*=======================*/ - /* out: checksum */ - byte* page); /* in: buffer page */ + /* out: checksum */ + byte* page); /* in: buffer page */ /************************************************************************ Checks if a page is corrupt. */ @@ -648,7 +648,7 @@ Sets the io_fix flag to BUF_IO_READ and sets a non-recursive exclusive lock on the buffer frame. The io-handler must take care that the flag is cleared and the lock released later. This is one of the functions which perform the state transition NOT_USED => FILE_PAGE to a block (the other is -buf_page_create). */ +buf_page_create). */ buf_block_t* buf_page_init_for_read( @@ -704,7 +704,7 @@ buf_get_free_list_len(void); /*=======================*/ - + /* The buffer control block structure */ struct buf_block_struct{ @@ -745,8 +745,6 @@ struct buf_block_struct{ buffer pool which are index pages, but this flag is not set because we do not keep track of all pages */ - dict_index_t* index; /* index for which the adaptive - hash index has been created */ /* 2. Page flushing fields */ UT_LIST_NODE_T(buf_block_t) flush_list; @@ -820,7 +818,7 @@ struct buf_block_struct{ /* 5. Hash search fields: NOTE that the first 4 fields are NOT protected by any semaphore! */ - + ulint n_hash_helps; /* counter which controls building of a new hash index for the page */ ulint n_fields; /* recommended prefix length for hash @@ -832,8 +830,14 @@ struct buf_block_struct{ whether the leftmost record of several records with the same prefix should be indexed in the hash index */ - - /* The following 4 fields are protected by btr_search_latch: */ + + /* These 6 fields may only be modified when we have + an x-latch on btr_search_latch AND + a) we are holding an s-latch or x-latch on block->lock or + b) we know that block->buf_fix_count == 0. + + An exception to this is when we init or create a page + in the buffer pool in buf0buf.c. */ ibool is_hashed; /* TRUE if hash index has already been built on this page; note that it does @@ -850,6 +854,8 @@ struct buf_block_struct{ ulint curr_side; /* BTR_SEARCH_LEFT_SIDE or BTR_SEARCH_RIGHT_SIDE in hash indexing */ + dict_index_t* index; /* Index for which the adaptive + hash index has been created. */ /* 6. Debug fields */ #ifdef UNIV_SYNC_DEBUG rw_lock_t debug_latch; /* in the debug version, each thread @@ -857,9 +863,9 @@ struct buf_block_struct{ an s-latch here; so we can use the debug utilities in sync0rw */ #endif - ibool file_page_was_freed; - /* this is set to TRUE when fsp - frees a page in buffer pool */ + ibool file_page_was_freed; + /* this is set to TRUE when fsp + frees a page in buffer pool */ }; #define BUF_BLOCK_MAGIC_N 41526563 @@ -971,7 +977,7 @@ struct buf_pool_struct{ physical memory is mapped to a frame */ UT_LIST_BASE_NODE_T(buf_block_t) LRU; /* base node of the LRU list */ - buf_block_t* LRU_old; /* pointer to the about 3/8 oldest + buf_block_t* LRU_old; /* pointer to the about 3/8 oldest blocks in the LRU list; NULL if LRU length less than BUF_LRU_OLD_MIN_LEN */ ulint LRU_old_len; /* length of the LRU list from @@ -1013,8 +1019,8 @@ MEMORY: is not in free list, LRU list, or flush list, nor page FILE_PAGE: space and offset are defined, is in page hash table if io_fix == BUF_IO_WRITE, pool: no_flush[block->flush_type] is in reset state, - pool: n_flush[block->flush_type] > 0 - + pool: n_flush[block->flush_type] > 0 + (1) if buf_fix_count == 0, then is in LRU list, not in free list is in flush list, @@ -1023,23 +1029,23 @@ FILE_PAGE: space and offset are defined, is in page hash table if and only if io_fix == BUF_IO_READ is s-locked, if and only if io_fix == BUF_IO_WRITE - + (2) if buf_fix_count > 0, then is not in LRU list, not in free list is in flush list, if and only if oldest_modification > 0 - if io_fix == BUF_IO_READ, + if io_fix == BUF_IO_READ, is x-locked if io_fix == BUF_IO_WRITE, is s-locked - + State transitions: NOT_USED => READY_FOR_USE READY_FOR_USE => MEMORY READY_FOR_USE => FILE_PAGE MEMORY => NOT_USED -FILE_PAGE => NOT_USED NOTE: This transition is allowed if and only if +FILE_PAGE => NOT_USED NOTE: This transition is allowed if and only if (1) buf_fix_count == 0, (2) oldest_modification == 0, and (3) io_fix == 0. |