diff options
Diffstat (limited to 'sql/field.cc')
| -rw-r--r-- | sql/field.cc | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/sql/field.cc b/sql/field.cc index fe3aebce05d..91dc1deb360 100644 --- a/sql/field.cc +++ b/sql/field.cc @@ -36,6 +36,8 @@ #include "tztime.h" // struct Time_zone #include "filesort.h" // change_double_for_sort #include "log_event.h" // class Table_map_log_event +#include "sql_statistics.h" +#include "sql_partition.h" #include <m_ctype.h> // Maximum allowed exponent value for converting string to decimal @@ -1851,6 +1853,7 @@ Field::Field(uchar *ptr_arg,uint32 length_arg,uchar *null_ptr_arg, field_index= 0; cond_selectivity= 1.0; next_equal_field= NULL; + stats_available= 0; } @@ -11358,6 +11361,203 @@ void Field::print_key_value_binary(String *out, const uchar* key, uint32 length) } +/* + @brief + Check if statistics for a column are available via keys + + @details + If the column is the first component of a key, then statistics + for the column are available from the range optimizer. + Sets the bit in Field::stats_table + a) NDV is available + b) Statistics are available for the non-const argument of a + range predicate +*/ + +void Field::statistics_available_via_keys() +{ + uint key; + key_map::Iterator it(key_start); + while ((key= it++) != key_map::Iterator::BITMAP_END) + { + KEY *keyinfo= table->key_info + key; + if (keyinfo->usable_key_parts == 1 && + field_index + 1 == keyinfo->key_part->fieldnr) + { + stats_available|= (1 << STATISTICS_FOR_RANGE_PREDICATES_AVAILABLE); + return; + } + } +} + + +/* + @brief + Check if statistics for a column are available via stat tables +*/ + +void Field::statistics_available_via_stat_tables() +{ + THD *thd= table->in_use; + if (!(check_eits_preferred(thd) && + thd->variables.optimizer_use_condition_selectivity > 2)) + return; + if (!(table->stats_is_read && + read_stats && !read_stats->no_stat_values_provided())) + return; + stats_available|= (1 << STATISTICS_FOR_RANGE_PREDICATES_AVAILABLE); + if (!read_stats->is_null(COLUMN_STAT_AVG_FREQUENCY)) + stats_available|= (1 << STATISTICS_FOR_NDV_AVAILABLE); +} + + +/* + @brief + Check if statistics for a column are available via indexes or stat tables + + @retval + TRUE : statistics available for the column + FALSE : OTHERWISE +*/ + +bool Field::is_statistics_available_for_range_predicates() +{ + if (!(stats_available & (1 << STATISTICS_CACHED))) + { + is_statistics_available(); + stats_available|= (1 << STATISTICS_CACHED); + } + return (stats_available & (1 << STATISTICS_FOR_RANGE_PREDICATES_AVAILABLE)); +} + + +void Field::is_statistics_available() +{ + statistics_available_via_keys(); + statistics_available_via_stat_tables(); + is_ndv_available_via_keys(); + is_ndv_available_via_stat_tables(); +} + +/* + @brief + Check if ndv for a column are available via indexes or stat tables + + @retval + TRUE : ndv available for the column + FALSE : OTHERWISE +*/ + +bool Field::is_ndv_available() +{ + if (!(stats_available & (1 << STATISTICS_CACHED))) + { + is_statistics_available(); + stats_available|= (1 << STATISTICS_CACHED); + } + return (stats_available & (1 << STATISTICS_FOR_NDV_AVAILABLE)); +} + + +/* + @brief + Check if number of distinct values(ndv) for a column are available via keys + + @retval + TRUE : ndv available from keys + FALSE : otherwise +*/ + +bool Field::is_ndv_available_via_keys() +{ + uint key; + key_map::Iterator it(key_start); + while ((key= it++) != key_map::Iterator::BITMAP_END) + { + KEY *keyinfo= table->key_info + key; + if (is_first_component_of_key(keyinfo) && keyinfo->actual_rec_per_key(0)) + { + stats_available|= (1 << STATISTICS_FOR_NDV_AVAILABLE); + return true; + } + } + return false; +} + + +/* + @brief + Check if ndv for a column are available via statistical tables + + @retval + TRUE : ndv available from statistical tables + FALSE : otherwise +*/ + +bool Field::is_ndv_available_via_stat_tables() +{ + if (!check_eits_preferred(table->in_use)) + return false; + if (!(read_stats && !read_stats->no_stat_values_provided() && + !read_stats->is_null(COLUMN_STAT_AVG_FREQUENCY))) + return false; + stats_available|= (1 << STATISTICS_FOR_NDV_AVAILABLE); + return true; +} + + +/* + @brief + Checks if a field is the first component of a given key + + @param + key given key + + @retval + TRUE : field is the first component of the given key + FALSE : otherwise +*/ + +bool Field::is_first_component_of_key(KEY *key) +{ + DBUG_ASSERT(key->usable_key_parts >= 1); + return field_index + 1 == key->key_part->fieldnr; +} + + +/* + Check whether EITS statistics for a field are usable or not + + TRUE : Use EITS for the columns + FALSE: Otherwise +*/ + +bool Field::is_eits_usable() +{ + // check if column_statistics was allocated for this field + if (!read_stats) + return false; + + DBUG_ASSERT(table->stats_is_read); + + /* + (1): checks if we have EITS statistics for a particular column + (2): Don't use EITS for GEOMETRY columns + (3): Disabling reading EITS statistics for columns involved in the + partition list of a table. We assume the selectivity for + such columns would be handled during partition pruning. + */ + + return !read_stats->no_stat_values_provided() && //(1) + type() != MYSQL_TYPE_GEOMETRY && //(2) +#ifdef WITH_PARTITION_STORAGE_ENGINE + (!table->part_info || + !table->part_info->field_in_partition_expr(this)) && //(3) +#endif + true; +} + + Virtual_column_info* Virtual_column_info::clone(THD *thd) { Virtual_column_info* dst= new (thd->mem_root) Virtual_column_info(*this); |