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Addressed all remaining issues from the review of the patch

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that introduced engine independent persistent statistics.
In particular:
- added an enumeration type for possible values of the system
  variable use_stat_tables
- renamed KEY::real_rec_per_key to KEY::actual_rec_per_key
- optimized the collection of statistical data for any primary
  key defined only on one column.
This commit is contained in:
Igor Babaev
2012-12-13 23:05:12 -08:00
parent 65820439bd
commit a06224bd15
16 changed files with 112 additions and 45 deletions
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62
sql/sql_statistics.cc
View File

@ -206,6 +206,8 @@ private:
Count_distinct_field *count_distinct; /* The container for distinct
column values */
bool is_single_pk_col; /* TRUE <-> the only column of the primary key */
public:
inline void init(THD *thd, Field * table_field);
@ -1399,6 +1401,8 @@ private:
public:
bool is_single_comp_pk;
Index_prefix_calc(TABLE *table, KEY *key_info)
: index_table(table), index_info(key_info)
{
@ -1407,6 +1411,16 @@ public:
uint key_parts= table->actual_n_key_parts(key_info);
empty= TRUE;
prefixes= 0;
is_single_comp_pk= FALSE;
uint pk= table->s->primary_key;
if (table->key_info - key_info == pk && table->key_info[pk].key_parts == 1)
{
prefixes= 1;
is_single_comp_pk= TRUE;
return;
}
if ((calc_state=
(Prefix_calc_state *) sql_alloc(sizeof(Prefix_calc_state)*key_parts)))
{
@ -1430,6 +1444,7 @@ public:
}
}
/**
@breif
Change the elements of calc_state after reading the next index entry
@ -1487,6 +1502,13 @@ public:
{
uint i;
Prefix_calc_state *state;
if (is_single_comp_pk)
{
index_info->collected_stats->set_avg_frequency(0, 1.0);
return;
}
for (i= 0, state= calc_state; i < prefixes; i++, state++)
{
if (i < prefixes)
@ -1658,7 +1680,7 @@ void create_min_max_stistical_fields_for_table_share(THD *thd,
int alloc_statistics_for_table(THD* thd, TABLE *table)
{
Field **field_ptr;
uint cnt= 0;
uint fields;
DBUG_ENTER("alloc_statistics_for_table");
@ -1666,10 +1688,11 @@ int alloc_statistics_for_table(THD* thd, TABLE *table)
(Table_statistics *) alloc_root(&table->mem_root,
sizeof(Table_statistics));
for (field_ptr= table->field; *field_ptr; field_ptr++, cnt++) ;
fields= table->s->fields ;
Column_statistics_collected *column_stats=
(Column_statistics_collected *) alloc_root(&table->mem_root,
sizeof(Column_statistics_collected) * cnt);
sizeof(Column_statistics_collected) *
fields);
uint keys= table->s->keys;
Index_statistics *index_stats=
@ -1688,7 +1711,7 @@ int alloc_statistics_for_table(THD* thd, TABLE *table)
table_stats->index_stats= index_stats;
table_stats->idx_avg_frequency= idx_avg_frequency;
memset(column_stats, 0, sizeof(Column_statistics) * cnt);
memset(column_stats, 0, sizeof(Column_statistics) * fields);
for (field_ptr= table->field; *field_ptr; field_ptr++, column_stats++)
(*field_ptr)->collected_stats= column_stats;
@ -1838,13 +1861,23 @@ inline
void Column_statistics_collected::init(THD *thd, Field *table_field)
{
uint max_heap_table_size= thd->variables.max_heap_table_size;
TABLE *table= table_field->table;
uint pk= table->s->primary_key;
is_single_pk_col= FALSE;
if (pk != MAX_KEY && table->key_info[pk].key_parts == 1 &&
table->key_info[pk].key_part[0].fieldnr == table_field->field_index + 1)
is_single_pk_col= TRUE;
column= table_field;
set_all_nulls();
nulls= 0;
column_total_length= 0;
if (is_single_pk_col)
count_distinct= NULL;
if (table_field->flags & BLOB_FLAG)
count_distinct= NULL;
else
@ -1923,6 +1956,12 @@ void Column_statistics_collected::finish(ha_rows rows)
delete count_distinct;
count_distinct= NULL;
}
else if (is_single_pk_col)
{
val= 1.0;
set_avg_frequency(val);
set_not_null(COLUMN_STAT_AVG_FREQUENCY);
}
}
@ -1986,6 +2025,12 @@ int collect_statistics_for_index(THD *thd, TABLE *table, uint index)
DEBUG_SYNC(table->in_use, "statistics_collection_start1");
DEBUG_SYNC(table->in_use, "statistics_collection_start2");
if (index_prefix_calc.is_single_comp_pk)
{
index_prefix_calc.get_avg_frequency();
DBUG_RETURN(rc);
}
table->key_read= 1;
table->file->extra(HA_EXTRA_KEYREAD);
@ -2078,7 +2123,7 @@ int collect_statistics_for_table(THD *thd, TABLE *table)
table->collected_stats->cardinality_is_null= TRUE;
table->collected_stats->cardinality= 0;
for (field_ptr= table->field; *field_ptr; field_ptr++)
{
table_field= *field_ptr;
@ -2949,9 +2994,9 @@ int rename_column_in_stat_tables(THD *thd, TABLE *tab, Field *col,
void set_statistics_for_table(THD *thd, TABLE *table)
{
uint use_stat_table_mode= thd->variables.use_stat_tables;
Use_stat_tables_mode use_stat_table_mode= get_use_stat_tables_mode(thd);
table->used_stat_records=
(use_stat_table_mode <= 1 ||
(use_stat_table_mode <= COMPLEMENTARY ||
!table->s->stats_is_read || !table->s->read_stats ||
table->s->read_stats->cardinality_is_null) ?
table->file->stats.records : table->s->read_stats->cardinality;
@ -2960,7 +3005,8 @@ void set_statistics_for_table(THD *thd, TABLE *table)
key_info < key_info_end; key_info++)
{
key_info->is_statistics_from_stat_tables=
(use_stat_table_mode > 1 && table->s->stats_is_read &&
(use_stat_table_mode > COMPLEMENTARY &&
table->s->stats_is_read &&
key_info->read_stats &&
key_info->read_stats->avg_frequency_is_inited() &&
key_info->read_stats->get_avg_frequency(0) > 0.5);