statement that uses an aggregating IN subquery with
HAVING clause.
A wrong order of the call of split_sum_func2 for the HAVING
clause of the subquery and the transformation for the
subquery resulted in the creation of a andor structure
that could not be restored at an execution of the prepared
statement.
containing a select statement that uses an aggregating IN subquery.
Added a parameter to the function fix_prepare_information
to restore correctly the having clause for the second execution.
Saved andor structure of the having conditions at the proper moment
before any calls of split_sum_func2 that could modify the having structure
adding new Item_ref objects. (These additions, are produced not with
the statement mem_root, but rather with the execution mem_root.)
In practice this means that handlerton is now created by the server and is passed to the engine. Plugin startups can now also control how plugins are inited (and can optionally pass values). Bit more flexibility to those who want to write plugin interfaces to the database.
equal constant under any circumstances.
In fact this substitution can be allowed if the field is
not of a type string or if the field reference serves as
an argument of a comparison predicate.
Select_type in the EXPLAIN output for the query SELECT * FROM t1 was
'SIMPLE', while for the query SELECT * FROM v1, where the view v1
was defined as SELECT * FROM t1, the EXPLAIN output contained 'PRIMARY'
for the select_type column.
The problem was due to a prior fix for BUG 9676, which limited
the rows stored in a temporary table to the LIMIT clause. This
optimization is not applicable to non-group queries with aggregate
functions. The fix disables the optimization in this case.
account by the optimizer.
Now all row equalities are converted into conjunctions of
equalities between row elements. They are taken into account
by the optimizer together with the original regular equality
predicates.
const tables. This resulted in choosing extremely inefficient
execution plans in same cases when distribution of data in
joined were skewed (see the customer test case for the bug).
GROUP BY/DISTINCT pruning optimization must be done before ORDER BY
optimization because ORDER BY may be removed when GROUP BY/DISTINCT
sorts as a side effect, e.g. in
SELECT DISTINCT <non-key-col>,<pk> FROM t1
ORDER BY <non-key-col> DISTINCT
must be removed before ORDER BY as if done the other way around
it will remove both.
used.
Sorting by RAND() uses a temporary table in order to get a correct results.
User defined variable was set during filling the temporary table and later
on it is substituted for its value from the temporary table. Due to this
it contains the last value stored in the temporary table.
Now if the result_field is set for the Item_func_set_user_var object it
updates variable from the result_field value when being sent to a client.
The Item_func_set_user_var::check() now accepts a use_result_field
parameter. Depending on its value the result_field or the args[0] is used
to get current value.
from cache" and #21216 "Simultaneous DROP TABLE and SHOW OPEN TABLES causes
server to crash".
Crash happened when one ran DROP DATABASE or SHOW OPEN TABLES statements
while concurrently doing DROP TABLE (or RENAME TABLE, CREATE TABLE LIKE
or any other command that takes name-lock) in other connection.
This problem was caused by the fact that table placeholders which were
added to table cache in order to obtain name-lock on table had
TABLE_SHARE::db and table_name set to 0. Therefore they broke assumption
that these members are non-0 for all tables in table cache on which some
of our code relies.
The fix sets these members for such placeholders to appropriate value making
this assumption true again. As attempt to avoid such problems in future
we introduce auxiliary TABLE_SHARE::set_table_cache_key() methods which
should be used when one wants to set TABLE_SHARE::table_cache_key and which
ensure that TABLE_SHARE::table_name/db are set properly.
Test cases for these bugs were added to 5.0 test-suite (with 5.0-specific
fix for bug #21216).
A date can be represented as an int (like 20060101) and as a string (like
"2006.01.01"). When a DATE/TIME field is compared in one SELECT against both
representations the constant propagation mechanism leads to comparison
of DATE as a string and DATE as an int. In this example it compares 2006 and
20060101 integers. Obviously it fails comparison although they represents the
same date.
Now the Item_bool_func2::fix_length_and_dec() function sets the comparison
context for items being compared. I.e. if items compared as strings the
comparison context is STRING.
The constant propagation mechanism now doesn't mix items used in different
comparison contexts. The context check is done in the
Item_field::equal_fields_propagator() and in the change_cond_ref_to_const()
functions.
Also the better fix for bug 21159 is introduced.
SELECT right instead of INSERT right was required for an insert into to a view.
This wrong behaviour appeared after the fix for bug #20989. Its intention was
to ask only SELECT right for all tables except the very first for a complex
INSERT query. But that patch has done it in a wrong way and lead to asking
a wrong access right for an insert into a view.
The setup_tables_and_check_access() function now accepts two want_access
parameters. One will be used for the first table and the second for other
tables.
Disable const propagation for Item_hex_string.
This must be done because Item_hex_string->val_int() is not
the same as (Item_hex_string->val_str() in BINARY column)->val_int().
We cannot simply disable the replacement in a particular context (
e.g. <bin_col> = <int_col> AND <bin_col> = <hex_string>) since
Items don't know the context they are in and there are functions like
IF (<hex_string>, 'yes', 'no').
Note that this will disable some valid cases as well
(e.g. : <bin_col> = <hex_string> AND <bin_col2> = <bin_col>) but
there's no way to distinguish the valid cases without having the
Item's parent say something like : Item->set_context(Item::STRING_RESULT)
and have all the Items that contain other Items do that consistently.
optimizer does not honor IGNORE INDEX
- Allow an index to be used for sorting the table
instead of filesort only if it is not disabled by
IGNORE INDEX.
table in a join
The optimizer removes redundant columns in ORDER BY. It is considering
redundant every reference to const table column, e.g b in :
create table t1 (a int, b int, primary key(a));
select 1 from t1 order by b where a = 1
But it must not remove references to const table columns if the
const table is an outer table because there still can be 2 values :
the const value and NULL. e.g.:
create table t1 (a int, b int, primary key(a));
select t2.b c from t1 left join t1 t2 on (t1.a = t2.a and t2.a = 5)
order by c;
