too many open statements". The patch adds a new global variable
@@max_prepared_stmt_count. This variable limits the total number
of prepared statements in the server. The default value of
@@max_prepared_stmt_count is 16382. 16382 small statements
(a select against 3 tables with GROUP, ORDER and LIMIT) consume
100MB of RAM. Once this limit has been reached, the server will
refuse to prepare a new statement and return ER_UNKNOWN_ERROR
(unfortunately, we can't add new errors to 4.1 without breaking 5.0). The limit is changeable after startup
and can accept any value from 0 to 1 million. In case
the new value of the limit is less than the current
statement count, no new statements can be added, while the old
still can be used. Additionally, the current count of prepared
statements is now available through a global read-only variable
@@prepared_stmt_count.
gives wrong results". Implement previously missing
Item_row::cleanup. The bug is not repeatable in 5.0, probably
due to a coincidence: the problem is present in 5.0 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.
table.cc:
Fixing to use system_charset_info instead of default_charset_info.
Crash happened because the "ctype" array is empty in UCS2,
and thus cannot be used with my_isspace().
The reason why UCS2 appeared in this context was because of
of default_charset_info variable incorrectly substituted to my_isspace().
As functions check_db_name(), check_table_name() and check_column_name()
always get values in utf8, system_charset_info must be used instead.
ctype_ucs2_def.test, ctype_ucs2_def-master.opt, ctype_ucs2_def.result:
new file
For "count(*) while index_column = value" an index read
is done. It consists of an index scan and retrieval of
each key.
For efficiency reasons the index scan stores the key in
the special buffer 'lastkey2' once only. At the first
iteration it notes this fact with the flag
HA_STATE_RNEXT_SAME in 'info->update'.
For efficiency reasons, the key retrieval for blobs
does not allocate a new buffer, but uses 'lastkey2'...
Now I clear the HA_STATE_RNEXT_SAME flag whenever the
buffer has been polluted. In this case, the index scan
copies the key value again (and sets the flag again).
- Back porting of some changes in later releases
- Corrected valgrind support
- Removed work around for TZ needed in VisualStudio 6
- Don't restart master to add special settings from "<testcase>-master.opt",
if same settngs as running master, feature request in bug#12433
- With --reorder, keep tests with same *-master.opt content together,
to save even more master restarts
