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Merge remote-tracking branch '10.2' into 10.3

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Vicențiu Ciorbaru
2018-04-12 12:41:19 +03:00
parent 9c42b9038d 36c0116720
commit 65eefcdc60
145 changed files with 1961 additions and 423 deletions
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22
sql/sql_statistics.cc
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@ -3081,18 +3081,19 @@ bool statistics_for_tables_is_needed(THD *thd, TABLE_LIST *tables)
return FALSE;
/*
Do not read statistics for any query over non-user tables.
If the query references some statistical tables, but not all
of them, reading the statistics may lead to a deadlock
*/
Do not read statistics for any query that explicity involves
statistical tables, failure to to do so we may end up
in a deadlock.
*/
for (TABLE_LIST *tl= tables; tl; tl= tl->next_global)
{
if (!tl->is_view_or_derived() && tl->table)
{
TABLE_SHARE *table_share= tl->table->s;
if (table_share &&
(table_share->table_category != TABLE_CATEGORY_USER ||
table_share->tmp_table != NO_TMP_TABLE))
table_share->table_category != TABLE_CATEGORY_USER
&& is_stat_table(&tl->db, &tl->alias))
return FALSE;
}
}
@ -3767,6 +3768,15 @@ double get_column_range_cardinality(Field *field,
if (!col_stats)
return tab_records;
/*
Use statistics for a table only when we have actually read
the statistics from the stat tables. For example due to
chances of getting a deadlock we disable reading statistics for
a table.
*/
if (!table->stats_is_read)
return tab_records;
double col_nulls= tab_records * col_stats->get_nulls_ratio();