The problem was in incorrect handling of predicates involving
NULL as a constant value by the range optimizer.
For example, when creating a SEL_ARG node from a condition of
the form "field < const" (which would normally result in the
"NULL < field < const" SEL_ARG), the special case when "const"
is NULL was not taken into account, so "NULL < field < NULL"
was produced for the "field < NULL" condition.
As a result, SEL_ARG structures of this form could not be
further optimized which in turn could lead to incorrectly
constructed SEL_ARG trees. In particular, code assuming SEL_ARG
structures to always form a sequence of ordered disjoint
intervals could enter an infinite loop under some
circumstances.
Fixed by changing get_mm_leaf() so that for any sargable
predicate except "<=>" involving NULL as a constant, "empty"
SEL_ARG is returned, since such a predicate is always false.
The problem was in incorrect handling of predicates involving
NULL as a constant value by the range optimizer.
For example, when creating a SEL_ARG node from a condition of
the form "field < const" (which would normally result in the
"NULL < field < const" SEL_ARG), the special case when "const"
is NULL was not taken into account, so "NULL < field < NULL"
was produced for the "field < NULL" condition.
As a result, SEL_ARG structures of this form could not be
further optimized which in turn could lead to incorrectly
constructed SEL_ARG trees. In particular, code assuming SEL_ARG
structures to always form a sequence of ordered disjoint
intervals could enter an infinite loop under some
circumstances.
Fixed by changing get_mm_leaf() so that for any sargable
predicate except "<=>" involving NULL as a constant, "empty"
SEL_ARG is returned, since such a predicate is always false.
covering index
When two range predicates were combined under an OR
predicate, the algorithm tried to merge overlapping ranges
into one. But the case when a range overlapped several other
ranges was not handled. This lead to
1) ranges overlapping, which gave repeated results and
2) a range that overlapped several other ranges was cut off.
Fixed by
1) Making sure that a range got an upper bound equal to the
next range with a greater minimum.
2) Removing a continue statement
can lead to bad memory access
Problem: Field_bit is the only field which returns INT_RESULT
and doesn't have unsigned flag. As it's not a descendant of the
Field_num, so using ((Field_num *) field_bit)->unsigned_flag may lead
to unpredictable results.
Fix: check the field type before casting.
results in server crash
check_group_min_max_predicates() assumed the input condition
item to be one of COND_ITEM, SUBSELECT_ITEM, or FUNC_ITEM.
Since a condition of the form "field" is also a valid condition
equivalent to "field <> 0", using such a condition in a query
where the loose index scan was chosen resulted in a debug
assertion failure.
Fixed by handling conditions of the FIELD_ITEM type in
check_group_min_max_predicates().
with gcc 4.3.2
This patch fixes a number of GCC warnings about variables used
before initialized. A new macro UNINIT_VAR() is introduced for
use in the variable declaration, and LINT_INIT() usage will be
gradually deprecated. (A workaround is used for g++, pending a
patch for a g++ bug.)
GCC warnings for unused results (attribute warn_unused_result)
for a number of system calls (present at least in later
Ubuntus, where the usual void cast trick doesn't work) are
also fixed.
Problem was that the partition containing NULL values
was pruned away, since '2001-01-01' < '2001-02-00' but
TO_DAYS('2001-02-00') is NULL.
Added the NULL partition for RANGE/LIST partitioning on TO_DAYS()
function to be scanned too.
Also fixed a bug that added ALLOW_INVALID_DATES to sql_mode
(SELECT * FROM t WHERE date_col < '1999-99-99' on a RANGE/LIST
partitioned table would add it).
There were a problem since pruning uses the field
for comparison (while evaluate_join_record uses longlong),
resulting in pruning failures when comparing DATE to DATETIME.
Fix was to always comparing DATE vs DATETIME as DATETIME,
by adding ' 00:00:00' to the DATE string.
And adding optimization for comparing with 23:59:59, so that
DATETIME_col > '2001-02-03 23:59:59' ->
TO_DAYS(DATETIME_col) > TO_DAYS('2001-02-03 23:59:59') instead
of '>='.
The code was using a special global buffer for the value of IS NULL ranges.
This was not always long enough to be copied by a regular memcpy. As a
result read buffer overflows may occur.
Fixed by setting the null byte to 1 and setting the rest of the field disk image
to NULL with a bzero (instead of relying on the buffer and memcpy()).
The check for stack overflow was independent of the size of the
structure stored in the heap.
Fixed by adding sizeof(PARAM) to the requested free heap size.
When the function exits with an error it was not
freeing the local Unique class instance.
Fixed my making sure all the places where the function
returns from are freeing the Unique instance
WHERE and GROUP BY clause
Loose index scan may use range conditions on the argument of
the MIN/MAX aggregate functions to find the beginning/end of
the interval that satisfies the range conditions in a single go.
These range conditions may have open or closed minimum/maximum
values. When the comparison returns 0 (equal) the code should
check the type of the min/max values of the current interval
and accept or reject the row based on whether the limit is
open or not.
There was a wrong composite condition on checking this and it was
not working in all cases.
Fixed by simplifying the conditions and reversing the logic.
Range analysis did not request sorted output from the storage engine,
which cause partitioned handlers to process one partition at a time
while reading key prefixes in ascending order, causing values to be
missed. Fixed by always requesting sorted order during range analysis.
This fix is introduced in 6.0 by the fix for bug no 41136.
with gcc 4.3.2
Compiling MySQL with gcc 4.3.2 and later produces a number of
warnings, many of which are new with the recent compiler
versions.
This bug will be resolved in more than one patch to limit the
size of changesets. This is the first patch, fixing a number
of the warnings, predominantly "suggest using parentheses
around && in ||", and empty for and while bodies.
with gcc 4.3.2
Compiling MySQL with gcc 4.3.2 and later produces a number of
warnings, many of which are new with the recent compiler
versions.
This bug will be resolved in more than one patch to limit the
size of changesets. This is the first patch, fixing a number
of the warnings, predominantly "suggest using parentheses
around && in ||", and empty for and while bodies.
return no rows
The algorithm of determining the best key for loose index scan is doing a loop
over the available indexes and selects the one that has the best cost.
It retrieves the parameters of the current index into a set of variables.
If the cost of using the current index is lower than the best cost so far it
copies these variables into another set of variables that contain the
information for the best index so far.
After having checked all the indexes it uses these variables (outside of the
index loop) to create the table read plan object instance.
The was a single omission : the key_infix/key_infix_len variables were used
outside of the loop without being preserved in the loop for the best index
so far.
This causes these variables to get overwritten by the next index(es) checked.
Fixed by adding variables to hold the data for the current index, passing
the new variables to the function that assigns values to them and copying
the new variables into the existing ones when selecting a new current best
index.
To avoid further such problems moved the declarations of the variables used
to keep information about the current index inside the loop's compound
statement.
- Add support for setting it as a server commandline argument
- Add support for those switches:
= no_index_merge
= no_index_merge_union
= no_index_merge_sort_union
= no_index_merge_intersection
- Remove bothersome warning messages. This change focuses on the warnings
that are covered by the ignore file: support-files/compiler_warnings.supp.
- Strings are guaranteed to be max uint in length
- QUICK_INDEX_MERGE_SELECT deinitializes its rnd_pos() scan when it reaches EOF, but we
need to make the deinitialization in QUICK_INDEX_MERGE_SELECT destructor also. This is because
certain execution strategies can stop scanning without reaching EOF, then then try to do a full
table scan on this table. Failure to deinitialize caused the full scan to use (already empty)
table->sort and produce zero records.
Field_varstring::store
The code that temporary saved the bitmaps of the read set and the write set so that
it can set it to all columns for debug purposes was not expecting that the
table->read_set and table->write_set can be the same. And was always saving both in
sequence.
As a result the original value was never restored.
Fixed by saving & restoring the original value only once if the two sets are the
same (in a special set of functions).
Select with a "NULL NOT IN" condition containing complex
subselect from the same table as in the outer select failed
with an assertion.
The failure was caused by a concatenation of circumstances:
1) an inner select was optimized by make_join_statistics to use
the QUICK_RANGE_SELECT access method (that implies an index
scan of the table);
2) a subselect was independent (constant) from the outer select;
3) a condition was pushed down into inner select.
During the evaluation of a constant IN expression an optimizer
temporary changed the access method from index scan to table
scan, but an engine handler was already initialized for index
access by make_join_statistics. That caused an assertion.
Unnecessary index initialization has been removed from
the QUICK_RANGE_SELECT::init method (QUICK_RANGE_SELECT::reset
reinvokes this initialization).
crashes server
When creating temporary table that contains aggregate functions a
non-reversible source transformation was performed to redirect aggregate
function arguments towards temporary table columns.
This caused EXPLAIN EXTENDED to fail because it was trying to resolve
references to the (freed) temporary table.
Fixed by preserving the original aggregate function arguments and
using them (instead of the transformed ones) for EXPLAIN EXTENDED.
problems are located in the sql_partition.cc where functions calculation
partition_id don't expect error returned from item->val_int().
Fixed by adding checks to these functions.
Note - it tries to fix more problems than just the reported bug.
per-file comments:
modified:
mysql-test/r/partition.result
Bug#38083 Error-causing row inserted into partitioned table despite error
test result
mysql-test/t/partition.test
Bug#38083 Error-causing row inserted into partitioned table despite error
test case
sql/opt_range.cc
Bug#38083 Error-causing row inserted into partitioned table despite error
get_part_id() call fixed
sql/partition_info.h
Bug#38083 Error-causing row inserted into partitioned table despite error
get_subpart_id_func interface changed.
sql/sql_partition.cc
Bug#38083 Error-causing row inserted into partitioned table despite error
various functions calculationg partition_id and subpart_id didn't expect
an error returned from item->val_int(). Error checks added.
