diff options
Diffstat (limited to 'innobase/btr/btr0sea.c')
| -rw-r--r-- | innobase/btr/btr0sea.c | 92 |
1 files changed, 71 insertions, 21 deletions
diff --git a/innobase/btr/btr0sea.c b/innobase/btr/btr0sea.c index 31f001ee769..de3fe6e196e 100644 --- a/innobase/btr/btr0sea.c +++ b/innobase/btr/btr0sea.c @@ -19,6 +19,9 @@ Created 2/17/1996 Heikki Tuuri #include "btr0btr.h" #include "ha0ha.h" +ulint btr_search_this_is_zero = 0; /* A dummy variable to fool the + compiler */ + ulint btr_search_n_succ = 0; ulint btr_search_n_hash_fail = 0; @@ -56,16 +59,20 @@ before hash index building is started */ /************************************************************************ Builds a hash index on a page with the given parameters. If the page already -has a hash index with different parameters, the old hash index is removed. */ +has a hash index with different parameters, the old hash index is removed. +If index is non-NULL, this function checks if n_fields and n_bytes are +sensible values, and does not build a hash index if not. */ static void btr_search_build_page_hash_index( /*=============================*/ - page_t* page, /* in: index page, s- or x-latched */ - ulint n_fields, /* in: hash this many full fields */ - ulint n_bytes, /* in: hash this many bytes from the next + dict_index_t* index, /* in: index for which to build, or NULL if + not known */ + page_t* page, /* in: index page, s- or x-latched */ + ulint n_fields,/* in: hash this many full fields */ + ulint n_bytes,/* in: hash this many bytes from the next field */ - ulint side); /* in: hash for searches from this side */ + ulint side); /* in: hash for searches from this side */ /********************************************************************* This function should be called before reserving any btr search mutex, if @@ -173,7 +180,9 @@ btr_search_info_create( } /************************************************************************* -Updates the search info of an index about hash successes. */ +Updates the search info of an index about hash successes. NOTE that info +is NOT protected by any semaphore, to save CPU time! Do not assume its fields +are consistent. */ static void btr_search_info_update_hash( @@ -295,7 +304,9 @@ set_new_recomm: } /************************************************************************* -Updates the block search info on hash successes. */ +Updates the block search info on hash successes. NOTE that info and +block->n_hash_helps, n_fields, n_bytes, side are NOT protected by any +semaphore, to save CPU time! Do not assume the fields are consistent. */ static ibool btr_search_update_block_hash_info( @@ -425,12 +436,19 @@ btr_search_info_update_slow( { buf_block_t* block; ibool build_index; - + ulint* params; + ulint* params2; + ut_ad(!rw_lock_own(&btr_search_latch, RW_LOCK_SHARED) && !rw_lock_own(&btr_search_latch, RW_LOCK_EX)); block = buf_block_align(btr_cur_get_rec(cursor)); + /* NOTE that the following two function calls do NOT protect + info or block->n_fields etc. with any semaphore, to save CPU time! + We cannot assume the fields are consistent when we return from + those functions! */ + btr_search_info_update_hash(info, cursor); build_index = btr_search_update_block_hash_info(info, block, cursor); @@ -439,7 +457,7 @@ btr_search_info_update_slow( btr_search_check_free_space_in_heap(); } - + if (cursor->flag == BTR_CUR_HASH_FAIL) { /* Update the hash node reference, if appropriate */ @@ -453,10 +471,30 @@ btr_search_info_update_slow( } if (build_index) { - btr_search_build_page_hash_index(block->frame, - block->n_fields, - block->n_bytes, - block->side); + /* Note that since we did not protect block->n_fields etc. + with any semaphore, the values can be inconsistent. We have + to check inside the function call that they make sense. We + also malloc an array and store the values there to make sure + the compiler does not let the function call parameters change + inside the called function. It might be that the compiler + would optimize the call just to pass pointers to block. */ + + params = mem_alloc(3 * sizeof(ulint)); + params[0] = block->n_fields; + params[1] = block->n_bytes; + params[2] = block->side; + + /* Make sure the compiler cannot deduce the values and do + optimizations */ + + params2 = params + btr_search_this_is_zero; + + btr_search_build_page_hash_index(cursor->index, + block->frame, + params2[0], + params2[1], + params2[2]); + mem_free(params); } } @@ -974,16 +1012,20 @@ btr_search_drop_page_hash_when_freed( /************************************************************************ Builds a hash index on a page with the given parameters. If the page already -has a hash index with different parameters, the old hash index is removed. */ +has a hash index with different parameters, the old hash index is removed. +If index is non-NULL, this function checks if n_fields and n_bytes are +sensible values, and does not build a hash index if not. */ static void btr_search_build_page_hash_index( /*=============================*/ - page_t* page, /* in: index page, s- or x-latched */ - ulint n_fields, /* in: hash this many full fields */ - ulint n_bytes, /* in: hash this many bytes from the next + dict_index_t* index, /* in: index for which to build, or NULL if + not known */ + page_t* page, /* in: index page, s- or x-latched */ + ulint n_fields,/* in: hash this many full fields */ + ulint n_bytes,/* in: hash this many bytes from the next field */ - ulint side) /* in: hash for searches from this side */ + ulint side) /* in: hash for searches from this side */ { hash_table_t* table; buf_block_t* block; @@ -1026,9 +1068,17 @@ btr_search_build_page_hash_index( return; } + /* Check that the values for hash index build are sensible */ + if (n_fields + n_bytes == 0) { - return; + return; + } + + if (index && (dict_index_get_n_unique_in_tree(index) < n_fields + || (dict_index_get_n_unique_in_tree(index) == n_fields + && n_bytes > 0))) { + return; } /* Calculate and cache fold values and corresponding records into @@ -1187,8 +1237,8 @@ btr_search_move_or_delete_hash_entries( ut_a(n_fields + n_bytes > 0); - btr_search_build_page_hash_index(new_page, n_fields, n_bytes, - side); + btr_search_build_page_hash_index(NULL, new_page, n_fields, + n_bytes, side); ut_a(n_fields == block->curr_n_fields); ut_a(n_bytes == block->curr_n_bytes); ut_a(side == block->curr_side); |