a correct fix:
* store properly quoted table names in tables4repair/etc lists
* tell handle_request_for_tables whether the name is aalready properly quoted
* test cases for all uses of fix_table_name()
We assume all around the code that null_value==true is in sync
with NULL value returned by val_str()/val_decimal().
Item_sum_sum::val_decimal() erroneously returned a non-NULL value together
with null_value set to true. Fixing to return NULL instead.
The problem was caused by a merged semi-join, which contained a non-merged
semi-join, which used references to the top-level query in the left_expr.
When moving non-merged semi-join from the subquery to its parent, do not
forget to call fix_after_pullout for its Item_subselect. We need to do
that specifically, because non-merged semi-joins do not have their
IN-equality in the WHERE clause at this stage.
Fix get_quick_keys(): When building range tree from a condition
in form
keypart1=const AND (keypart2 < 0 OR keypart2>=0)
the SEL_ARG for keypart2 represents an interval (-inf, +inf).
However, the logic that sets UNIQUE_RANGE flag fails to recognize
this, and sets UNIQUE_RANGE flag if (keypart1, keypart2) covered
a unique key.
As a result, range access executor assumes the interval can have
at most one row and only reads the first row from it.
TABLE_SHARE::init_from_binary_frm_image has a rule: if an index
has a partially-covered column (like in "KEY(col(N))" ), then dont
provide "Extended Keys" feature for this index.
The problem was that due to coding error Extended Keys feature was
disabled for *ALL* subsequent indexes. Fixed the error.
The problem was introduced by 1859caf60b:
MDEV-10175: range optimizer calls records_in_range() for full extended keys
Make the range optimizer not call records_in_range() when it would
not give any benefit.
that patch used an incorrect way to check for full extended key. Now fixing
the check.
The crash was caused by this problem:
get_best_group_min_max() tries to construct query plans for keys that
are not processed by the range optimizer. This wasn't a problem as long
as SEL_TREE::keys was an array of MAX_KEY elements.
However, now it is a Mem_root_array and only has elements for the used
keys, and get_best_group_min_max attempts to address beyond the end of
the array.
The obvious way to fix the crash was to port (and improve) a part of
96fcfcbd7b5120e8f64fd45985001eca8d36fbfb from mysql-5.7. This makes
get_best_group_min_max not to consider indexes that Mem_root_arrays
have no element for.
After that, I got non-sensical query plans (see MDEV-10325 for details).
Fixed that by making get_best_group_min_max to check if the index is in
table->keys_in_use_for_group_by bitmap.
Item_cache::is_null() erroneously returned null_value in a
non-cached state. Now Item_cache::is_null() uses has_value(),
which caches the value if not cached yet, similar to what other value methods do
(e.g. val_int, val_real, etc).
The collation customization code for the UCA (Unicode Collation Alrorithm)
based collations now allows to reset to and shift of characters with
implicit weights. Previously reset/shift worked only for the characters
with explicit DUCET weights. An attempt to use reset/shift with
character with implicit weights made the server crash.
The patch fixes the problem with loading information from system tables
(e.g. event and help related tables) when PAD_CHAR_TO_FULL_LENGTH is enabled,
as well as includes some additional minor improvements:
- refactoring in get_field() to return an error rather than success
if strmake_root() failed
- removing of duplicate code in similar functions:
char *get_field(MEM_ROOT *mem, Field *field)
bool get_field(MEM_ROOT *mem, Field *field, String *res)
metadata_lock_info plugin called MDL_context::find_ticket() to obtain lock
duration, which in turn iterates foreign thread private lists. These lists
can be updated by owner thread without protection.
Fixed by iterating threads (instead of MDL locks and tickets) and obtaining
data through APC.
Also fixed mdl_iterate_lock() to initialize iterator under prlock protection.
