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| author | unknown <heikki@donna.mysql.fi> | 2001-12-17 12:17:07 +0200 |
|---|---|---|
| committer | unknown <heikki@donna.mysql.fi> | 2001-12-17 12:17:07 +0200 |
| commit | 56a8ad593e0f951b639b4978d5124b2424defe07 (patch) | |
| tree | 9b9ff300476c4df6b4b37067d7159cf921df81e1 /sql/ha_innobase.cc | |
| parent | 85a8f75a7d52e9c37f787a2dbea496e73a2e0043 (diff) | |
| download | mariadb-git-56a8ad593e0f951b639b4978d5124b2424defe07.tar.gz | |
ha_innobase.cc:
Do not automatically calculate new statistics when a temporary table is used by MySQL in a query. The fact that some ORDER BY queries were slow may have been explained by this unnecessary statistics calculation.
sql/ha_innobase.cc:
Do not automatically calculate new statistics when a temporary table is used by MySQL in a query. The fact that some ORDER BY queries were slow may have been explained by this unnecessary statistics calculation.
Diffstat (limited to 'sql/ha_innobase.cc')
| -rw-r--r-- | sql/ha_innobase.cc | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/sql/ha_innobase.cc b/sql/ha_innobase.cc index 093d4e91c30..81c28605eb7 100644 --- a/sql/ha_innobase.cc +++ b/sql/ha_innobase.cc @@ -3035,15 +3035,18 @@ ha_innobase::estimate_number_of_rows(void) DBUG_ENTER("info"); - dict_update_statistics(prebuilt->table); - index = dict_table_get_first_index_noninline(prebuilt->table); data_file_length = ((ulonglong) index->stat_n_leaf_pages) * UNIV_PAGE_SIZE; - /* Calculate a minimum length for a clustered index record */ - estimate = data_file_length / dict_index_calc_min_rec_len(index); + /* Calculate a minimum length for a clustered index record and from + that an upper bound for the number of rows. Since we only calculate + new statistics in row0mysql.c when a table size has grown by 50 % + or by a threshold factor, we must add a safety factor 2 in front + of the formula below. */ + + estimate = 2 * data_file_length / dict_index_calc_min_rec_len(index); if (prebuilt->trx) { prebuilt->trx->op_info = ""; |