diff options
| -rw-r--r-- | sql/sql_statistics.cc | 99 | ||||
| -rw-r--r-- | sql/table.cc | 2 | ||||
| -rw-r--r-- | sql/table.h | 75 |
3 files changed, 116 insertions, 60 deletions
diff --git a/sql/sql_statistics.cc b/sql/sql_statistics.cc index 0f8daa6e52f..a99dcca89e4 100644 --- a/sql/sql_statistics.cc +++ b/sql/sql_statistics.cc @@ -2204,27 +2204,13 @@ static int alloc_statistics_for_table_share(THD* thd, TABLE_SHARE *table_share) DBUG_ENTER("alloc_statistics_for_table_share"); - DEBUG_SYNC(thd, "statistics_mem_alloc_start1"); - DEBUG_SYNC(thd, "statistics_mem_alloc_start2"); - - mysql_mutex_lock(&table_share->LOCK_share); - - if (stats_cb->stats_can_be_read) - { - mysql_mutex_unlock(&table_share->LOCK_share); - DBUG_RETURN(0); - } - Table_statistics *table_stats= stats_cb->table_stats; if (!table_stats) { table_stats= (Table_statistics *) alloc_root(&stats_cb->mem_root, sizeof(Table_statistics)); if (!table_stats) - { - mysql_mutex_unlock(&table_share->LOCK_share); DBUG_RETURN(1); - } memset(table_stats, 0, sizeof(Table_statistics)); stats_cb->table_stats= table_stats; } @@ -2290,13 +2276,7 @@ static int alloc_statistics_for_table_share(THD* thd, TABLE_SHARE *table_share) } } } - - if (column_stats && index_stats && idx_avg_frequency) - stats_cb->stats_can_be_read= TRUE; - - mysql_mutex_unlock(&table_share->LOCK_share); - - DBUG_RETURN(0); + DBUG_RETURN(column_stats && index_stats && idx_avg_frequency ? 0 : 1); } @@ -2913,11 +2893,22 @@ int read_statistics_for_table(THD *thd, TABLE *table, TABLE_LIST *stat_tables) Field **field_ptr; KEY *key_info, *key_info_end; TABLE_SHARE *table_share= table->s; - Table_statistics *read_stats= table_share->stats_cb.table_stats; DBUG_ENTER("read_statistics_for_table"); + DEBUG_SYNC(thd, "statistics_mem_alloc_start1"); + DEBUG_SYNC(thd, "statistics_mem_alloc_start2"); + + if (!table_share->stats_cb.start_stats_load()) + DBUG_RETURN(table_share->stats_cb.stats_are_ready() ? 0 : 1); + + if (alloc_statistics_for_table_share(thd, table_share)) + { + table_share->stats_cb.abort_stats_load(); + DBUG_RETURN(1); + } /* Read statistics from the statistical table table_stats */ + Table_statistics *read_stats= table_share->stats_cb.table_stats; stat_table= stat_tables[TABLE_STAT].table; Table_stat table_stat(stat_table, table); table_stat.set_key_fields(); @@ -2995,9 +2986,7 @@ int read_statistics_for_table(THD *thd, TABLE *table, TABLE_LIST *stat_tables) } } } - - table->stats_is_read= TRUE; - + table_share->stats_cb.end_stats_load(); DBUG_RETURN(0); } @@ -3146,6 +3135,23 @@ int read_statistics_for_tables_if_needed(THD *thd, TABLE_LIST *tables) } +static void dump_stats_from_share_to_table(TABLE *table) +{ + TABLE_SHARE *table_share= table->s; + KEY *key_info= table_share->key_info; + KEY *key_info_end= key_info + table_share->keys; + KEY *table_key_info= table->key_info; + for ( ; key_info < key_info_end; key_info++, table_key_info++) + table_key_info->read_stats= key_info->read_stats; + + Field **field_ptr= table_share->field; + Field **table_field_ptr= table->field; + for ( ; *field_ptr; field_ptr++, table_field_ptr++) + (*table_field_ptr)->read_stats= (*field_ptr)->read_stats; + table->stats_is_read= true; +} + + int read_statistics_for_tables(THD *thd, TABLE_LIST *tables) { TABLE_LIST stat_tables[STATISTICS_TABLES]; @@ -3167,30 +3173,17 @@ int read_statistics_for_tables(THD *thd, TABLE_LIST *tables) { if (table_share->table_category == TABLE_CATEGORY_USER) { - if (table_share->stats_cb.stats_can_be_read || - !alloc_statistics_for_table_share(thd, table_share)) + if (table_share->stats_cb.stats_are_ready()) { - if (table_share->stats_cb.stats_can_be_read) - { - KEY *key_info= table_share->key_info; - KEY *key_info_end= key_info + table_share->keys; - KEY *table_key_info= tl->table->key_info; - for ( ; key_info < key_info_end; key_info++, table_key_info++) - table_key_info->read_stats= key_info->read_stats; - Field **field_ptr= table_share->field; - Field **table_field_ptr= tl->table->field; - for ( ; *field_ptr; field_ptr++, table_field_ptr++) - (*table_field_ptr)->read_stats= (*field_ptr)->read_stats; - tl->table->stats_is_read= table_share->stats_cb.stats_is_read; - tl->table->histograms_are_read= - table_share->stats_cb.histograms_are_read; - - if (!tl->table->stats_is_read || - (!table_share->stats_cb.histograms_are_read && - thd->variables.optimizer_use_condition_selectivity > 3)) - statistics_for_tables_is_needed= true; - } + if (!tl->table->stats_is_read) + dump_stats_from_share_to_table(tl->table); + tl->table->histograms_are_read= + table_share->stats_cb.histograms_are_read; + if (table_share->stats_cb.histograms_are_read || + thd->variables.optimizer_use_condition_selectivity <= 3) + continue; } + statistics_for_tables_is_needed= true; } else if (is_stat_table(tl->db, tl->alias)) found_stat_table= true; @@ -3217,16 +3210,14 @@ int read_statistics_for_tables(THD *thd, TABLE_LIST *tables) table_share->tmp_table == NO_TMP_TABLE && table_share->table_category == TABLE_CATEGORY_USER) { - if (table_share->stats_cb.stats_can_be_read && - !table_share->stats_cb.stats_is_read) + if (!tl->table->stats_is_read) { - (void) read_statistics_for_table(thd, tl->table, stat_tables); - table_share->stats_cb.stats_is_read= TRUE; + if (!read_statistics_for_table(thd, tl->table, stat_tables)) + dump_stats_from_share_to_table(tl->table); + else + continue; } - if (table_share->stats_cb.stats_is_read) - tl->table->stats_is_read= TRUE; if (thd->variables.optimizer_use_condition_selectivity > 3 && - table_share->stats_cb.stats_can_be_read && !table_share->stats_cb.histograms_are_read) { (void) read_histograms_for_table(thd, tl->table, stat_tables); diff --git a/sql/table.cc b/sql/table.cc index 192faa0d00e..1d3bebcc5d5 100644 --- a/sql/table.cc +++ b/sql/table.cc @@ -416,8 +416,6 @@ void TABLE_SHARE::destroy() delete_stat_values_for_table_share(this); free_root(&stats_cb.mem_root, MYF(0)); - stats_cb.stats_can_be_read= FALSE; - stats_cb.stats_is_read= FALSE; stats_cb.histograms_can_be_read= FALSE; stats_cb.histograms_are_read= FALSE; diff --git a/sql/table.h b/sql/table.h index 29b4cfdbcf3..85ba7b29ce2 100644 --- a/sql/table.h +++ b/sql/table.h @@ -594,15 +594,82 @@ enum open_frm_error { from persistent statistical tables */ -struct TABLE_STATISTICS_CB +class TABLE_STATISTICS_CB { + class Statistics_state + { + enum state_codes + { + EMPTY, /** data is not loaded */ + LOADING, /** data is being loaded in some connection */ + READY /** data is loaded and available for use */ + }; + int32 state; + + public: + /** No state copy */ + Statistics_state &operator=(const Statistics_state &) { return *this; } + + /** Checks if data loading have been completed */ + bool is_ready() const + { + return my_atomic_load32_explicit(const_cast<int32*>(&state), + MY_MEMORY_ORDER_ACQUIRE) == READY; + } + + /** + Sets mutual exclusion for data loading + + If stats are in LOADING state, waits until state change. + + @return + @retval true atomic EMPTY -> LOADING transfer completed, ok to load + @retval false stats are in READY state, no need to load + */ + bool start_load() + { + for (;;) + { + int32 expected= EMPTY; + if (my_atomic_cas32_weak_explicit(&state, &expected, LOADING, + MY_MEMORY_ORDER_RELAXED, + MY_MEMORY_ORDER_RELAXED)) + return true; + if (expected == READY) + return false; + (void) LF_BACKOFF; + } + } + + /** Marks data available for subsequent use */ + void end_load() + { + DBUG_ASSERT(my_atomic_load32_explicit(&state, MY_MEMORY_ORDER_RELAXED) == + LOADING); + my_atomic_store32_explicit(&state, READY, MY_MEMORY_ORDER_RELEASE); + } + + /** Restores empty state on error (e.g. OOM) */ + void abort_load() + { + DBUG_ASSERT(my_atomic_load32_explicit(&state, MY_MEMORY_ORDER_RELAXED) == + LOADING); + my_atomic_store32_explicit(&state, EMPTY, MY_MEMORY_ORDER_RELAXED); + } + }; + + class Statistics_state stats_state; + +public: MEM_ROOT mem_root; /* MEM_ROOT to allocate statistical data for the table */ Table_statistics *table_stats; /* Structure to access the statistical data */ - bool stats_can_be_read; /* Memory for statistical data is allocated */ - bool stats_is_read; /* Statistical data for table has been read - from statistical tables */ bool histograms_can_be_read; bool histograms_are_read; + + bool stats_are_ready() const { return stats_state.is_ready(); } + bool start_stats_load() { return stats_state.start_load(); } + void end_stats_load() { stats_state.end_load(); } + void abort_stats_load() { stats_state.abort_load(); } }; |