The problem was that during DROP TEMPORARY TABLE we tried to acquire
the name lock, though temporary tables belongs to one connection, and
no race is possible.
The solution is to not use table name locking while executing
DROP TEMPORARY TABLE.
- if there are two character set definitions in the column declaration,
we replace the first one with the second one as we store both in the LEX->charset
slot. Add a separate slot to the LEX structure to store underscore charset.
- convert default values to the column charset of STRING, VARSTRING fields
if necessary as well.
The GROUP_CONCAT uses its own temporary table. When ROLLUP is present
it creates the second copy of Item_func_group_concat. This copy receives the
same list of arguments that original group_concat does. When the copy is
set up the result_fields of functions from the argument list are reset to the
temporary table of this copy.
As a result of this action data from functions flow directly to the ROLLUP copy
and the original group_concat functions shows wrong result.
Since queries with COUNT(DISTINCT ...) use temporary tables to store
the results the COUNT function they are also affected by this bug.
The idea of the fix is to copy content of the result_field for the function
under GROUP_CONCAT/COUNT from the first temporary table to the second one,
rather than setting result_field to point to the second temporary table.
To achieve this goal force_copy_fields flag is added to Item_func_group_concat
and Item_sum_count_distinct classes. This flag is initialized to 0 and set to 1
into the make_unique() member function of both classes.
To the TMP_TABLE_PARAM structure is modified to include the similar flag as
well.
The create_tmp_table() function passes that flag to create_tmp_field().
When the flag is set the create_tmp_field() function will set result_field
as a source field and will not reset that result field to newly created
field for Item_func_result_field and its descendants. Due to this there
will be created copy func to copy data from old result_field to newly
created field.
column is increasing when table is recreated with PS/SP":
make use of create_field::char_length more consistent in the code.
Reinit create_field::length from create_field::char_length
for every execution of a prepared statement (actually fixes the
bug).
CREATE TABLE and PS/SP": make sure that 'typelib' object for
ENUM values and 'Item_string' object for DEFAULT clause are
created in the statement memory root.
Version for 4.0.
It fixes two problems:
1. The cause of the bug was that we did not check the table version for
the HANDLER ... READ commands. We did not notice when a table was
replaced by a new one. This can happen during ALTER TABLE, REPAIR
TABLE, and OPTIMIZE TABLE (there might be more cases). I call the fix
for this problem "the primary bug fix".
2. mysql_ha_flush() was not always called with a locked LOCK_open.
Though the function comment clearly said it must.
I changed the code so that the locking is done when required. I call
the fix for this problem "the secondary fix".
produce warning for 'create database if not exists' if database exists
do not update database options in this case
produce warning for 'create table if not exists' if table exists
We binlog the DROP TABLE for each table that was actually dropped. Per Sergei's
suggestion a fixed buffer for the DROP TABLE query is pre-allocated from THD pool, and
logging now is done in batches - new batch is started if the buffer becomes full.
Reduced memory usage by reusing the table list instead of accumulating a list of
dropped table names. Also fixed the problem if the table was not actually dropped, eg
due to permissions. Extended the test case to make sure batched query
logging does work.
adding test case
sql_table.cc:
sql_table.cc:
- do not create a new item when charsets are the same
- return ER_INVALID_DEFAULT if default value cannot
be converted into the column character set.
item.cc:
- Allow conversion not only to Unicode,
but also to and from "binary".
- Adding safe_charset_converter() for Item_num
and Item_varbinary, returning a fixed const Item.
- Added better error messages when trying to open a table that can't be discovered or unpacked. The most likely cause of this is that it does not have any frm data, probably since it has been created from NdbApi or is a NDB system table.
- Separated functionality that was in ha_create_table_from_engine into two functions. One that checks if the table exists and another one that tries to create the table from the engine.
Ensure that 'null_value' is not accessed before val() is called in FIELD() functions
Fixed initialization of key maps. This fixes some problems with keys when you have more than 64 keys
Fixed that ROLLUP don't always create a temporary table. This fix ensures that func_gconcat.test results are now predictable
1.) Added a new option to mysql_lock_tables() for ignoring FLUSH TABLES.
Used the new option in create_table_from_items().
It is necessary to prevent the SELECT table from being reopend.
It would get new storage assigned for its fields, while the
SELECT part of the command would still use the old (freed) storage.
2.) Protected the CREATE TABLE and CREATE TABLE ... SELECT commands
against a global read lock. This prevents a deadlock in
CREATE TABLE ... SELECT in conjunction with FLUSH TABLES WITH READ LOCK
and avoids the creation of new tables during a global read lock.
3.) Replaced set_protect_against_global_read_lock() and
unset_protect_against_global_read_lock() by
wait_if_global_read_lock() and start_waiting_global_read_lock()
in the INSERT DELAYED handling.
