diff options
Diffstat (limited to 'sql/sql_statistics.cc')
| -rw-r--r-- | sql/sql_statistics.cc | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/sql/sql_statistics.cc b/sql/sql_statistics.cc index 01947462cce..903ebb91d01 100644 --- a/sql/sql_statistics.cc +++ b/sql/sql_statistics.cc @@ -1801,6 +1801,7 @@ private: public: bool is_single_comp_pk; + bool is_partial_fields_present; Index_prefix_calc(THD *thd, TABLE *table, KEY *key_info) : index_table(table), index_info(key_info) @@ -1812,7 +1813,7 @@ public: prefixes= 0; LINT_INIT_STRUCT(calc_state); - is_single_comp_pk= FALSE; + is_partial_fields_present= is_single_comp_pk= FALSE; uint pk= table->s->primary_key; if ((uint) (table->key_info - key_info) == pk && table->key_info[pk].user_defined_key_parts == 1) @@ -1834,7 +1835,10 @@ public: calculating the values of 'avg_frequency' for prefixes. */ if (!key_info->key_part[i].field->part_of_key.is_set(keyno)) + { + is_partial_fields_present= TRUE; break; + } if (!(state->last_prefix= new (thd->mem_root) Cached_item_field(thd, @@ -2633,7 +2637,13 @@ int collect_statistics_for_index(THD *thd, TABLE *table, uint index) DBUG_RETURN(rc); } - table->file->ha_start_keyread(index); + /* + Request "only index read" in case of absence of fields which are + partially in the index to avoid problems with partitioning (for example) + which want to get whole field value. + */ + if (!index_prefix_calc.is_partial_fields_present) + table->file->ha_start_keyread(index); table->file->ha_index_init(index, TRUE); rc= table->file->ha_index_first(table->record[0]); while (rc != HA_ERR_END_OF_FILE) |