When optimizing conditions like 'a = <some_val> OR a IS NULL' so that they're
united into a single condition on the key and checked together the server must
check which value is the NULL value in a correct way : not only using ->is_null
but also check if the expression doesn't depend on any tables referenced in the
current statement.
This additional check must be performed because that optimization takes place
before the actual execution of the statement, so if the field was initialized
to NULL from a previous statement the optimization would be applied incorrectly.
The problem was in that opt_sum_query() replaced MIN/MAX functions
with the corresponding constant found in a key, but due to imprecise
representation of float numbers, when evaluating the where clause,
this comparison failed.
When MIN/MAX optimization detects that all tables can be removed,
also remove all conjuncts in a where clause that refer to these
tables. As a result of this fix, these conditions are not evaluated
twice, and in the case of float number comparisons we do not discard
result rows due to imprecise float representation.
As a side-effect this fix also corrects an unnoticed problem in
bug 12882.
Added test case for bug#18759 Incorrect string to numeric conversion.
select.test:
Added test case for bug#18759 Incorrect string to numeric conversion.
item_cmpfunc.cc:
Cleanup after fix for bug#18360 removal
3.23 regression test failure
The member SEL_ARG::min_flag was not initialized,
due to which the condition for no GEOM_FLAG in function
key_or did not choose "Range checked for each record" as
the correct access method.
crash
resolve_const_item() substitutes item which will evaluate to constant with
equvalent constant item, basing on the item's result type. In this case
subselect was resolved as constant, and resolve_const_item() was substituting
it's result's Item_caches to Item_null. Later Item_cache's function was called
for Item_null object, which caused server crash.
resolve_const_item() now substitutes constants for items with
result_type == ROW_RESULT only for Item_rows.
DISTINCT wasn't optimized away and caused creation of tmp table in wrong
case. This result in integer overrun and running out of memory.
Fix backported from 4.1. Now if optimizer founds that in result be only 1
row it removes distinct.
When fixing Item_func_plus in ORDER BY clause field c is searched in all
opened tables, but because c is an alias it wasn't found there.
This patch adds a flag to select_lex which allows Item_field::fix_fields()
to look up in select's item_list to find aliased fields.
After SHOW TABLE STATUS last_insert_id wasn't cleaned, and next select
erroneously rewrites WHERE condition and returs a row;
5.0 isn't affected because of different SHOW TABLE STATUS handling.
last_insert_id cleanup added to mysqld_extend_show_tables().
resolve_const_item() assumed to be not called for Item_row items. For
ensuring that DBUG_ASSERT(0) was set there.
This patch adds section for Item_row items. If it can it recursively calls
resolve_const_item() for each item the Item_row contains. If any of the
contained items is null then whole Item_row substitued by Item_null. Otherwise
it just returns.
Added a test case for bug #11745.
sql_select.cc:
Fixed bug # 11745.
Added support of where clause for queries with FROM DUAL.
sql_yacc.yy:
Fixed bug # 11745.
Added optional where clause for queries with FROM DUAL.
"Negative integer keys incorrectly substituted for 0 during range analysis."
The problem is that the range optimizer incorrectly replaces any negative
constant with '0' for all types except BIGINT because the method save_in_field()
casts negative integers to non-negative. This causes incorrect query
results where (0 = any_negative_number).
The problem caused by this bug is fixed by the patch for BUG#11185.
That patch constitutes an optimization due to which the problem code is
never called with negative constants. This patch adds a test so we are sure
that the problem does not reappear.
than in previous 4.1.x
Wrongly applied optimization were adding NOT NULL constraint which results in
rejecting valid rows and reduced result set.
The problem was that add_notnull_conds() while checking subquery were adding
NOT NULL constraint to left joined table, to which, normally, optimization
don't have to be applied.
(IN() remove NULL rows only for tables from first argument (value which we looking for in IN() list) but not for tables from IN() list)
Also it will be better change Item::not_null_tables() to prohibit this optimisation by default for new created items in 5.0 or 5.1.
The problem: base_list::remove didn't modify base_list::last when removing
the last list element.
The fix: If we remove the last element, find the element before it (by walking
from the beginning of the list) and set base_list::last accordingly.
The list gets corrupted in both 4.0 and 4.1. There are no visible problems in
current 4.1 because current 4.1 doesn't call where_cond->fix_fields() after
constant propagation step.
The reported problems were due to two completely unrelated omissions.
1) The file sort procedure didn't correctly create the sort key in
make_sortkey when the sortkey was an unsigned integer.
2) The name resolution procedure for column references inside a HAVING
clause did not propagate the unsigned_flag of the resolved references.
This patch corrects both problems.
Added a test case for bug #7098.
sql_select.cc:
Fixed bug #7098.
When a string field was substituted for an equal constant
the collation of the constant was changed by mistake for
the binary collation.
Added a test case for bug #7520.
table.cc:
Fixed bug #7520.
The bug was caused by a wrong calculation of the field max_key_length for
a TABLE structure when there was an index on a blob field.
