diff options
Diffstat (limited to 'sql/sql_select.cc')
| -rw-r--r-- | sql/sql_select.cc | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/sql/sql_select.cc b/sql/sql_select.cc index cd7b15e80b6..15bd6886682 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -14976,7 +14976,20 @@ create_tmp_table(THD *thd, TMP_TABLE_PARAM *param, List<Item> &fields, keyinfo->key_length= 0; // Will compute the sum of the parts below. keyinfo->name= (char*) "distinct_key"; keyinfo->algorithm= HA_KEY_ALG_UNDEF; - keyinfo->rec_per_key=0; + /* + Needed by non-merged semi-joins: SJ-Materialized table must have a valid + rec_per_key array, because it participates in join optimization. Since + the table has no data, the only statistics we can provide is "unknown", + i.e. zero values. + + (For table record count, we calculate and set JOIN_TAB::found_records, + see get_delayed_table_estimates()). + */ + size_t rpk_size= keyinfo->key_parts* sizeof(keyinfo->rec_per_key[0]); + if (!(keyinfo->rec_per_key= (ulong*) alloc_root(&table->mem_root, + rpk_size))) + goto err; + bzero(keyinfo->rec_per_key, rpk_size); /* Create an extra field to hold NULL bits so that unique indexes on |