MDEV-20001 Potential dangerous regression: INSERT INTO >=100 rows fail for myisam table with HASH indexes

Problem:-

So the issue is when we do bulk insert with rows
> MI_MIN_ROWS_TO_DISABLE_INDEXES(100) , We try to disable the indexes to
speedup insert. But current logic also disables the long unique indexes.

Solution:- In ha_myisam::start_bulk_insert if we find long hash index
(HA_KEY_ALG_LONG_HASH) we will not disable the index.

This commit also refactors the mi_disable_indexes_for_rebuild function,
Since this is function is called at only one place, it is inlined into
start_bulk_insert

mi_clear_key_active is added into myisamdef.h because now it is also used
in ha_myisam.cc file.

(Same is done for Aria Storage engine)

1 files changed, 1 insertions, 0 deletions

diff --git a/include/myisam.h b/include/myisam.h
index 216f041c8a9..f2e31bb9f60 100644
--- a/include/myisam.h
+++ b/include/myisam.h
@@ -430,6 +430,7 @@ int sort_ft_buf_flush(MI_SORT_PARAM *sort_param);
 int thr_write_keys(MI_SORT_PARAM *sort_param);
 int sort_write_record(MI_SORT_PARAM *sort_param);
 int _create_index_by_sort(MI_SORT_PARAM *info,my_bool no_messages, ulonglong);
+my_bool mi_too_big_key_for_sort(MI_KEYDEF *key, ha_rows rows);
 
 #ifdef	__cplusplus
 }