The bug was found by Alyssa Milburn.
If the number of points of a geometry feature read from
binary representation is greater than 0x10000000, then
the (uint32) (num_points * 16) will cut the higher byte,
which leads to various errors.
Fixed by additional check if (num_points > max_n_points).
This bug is a regression bug. The regression was introduced by
the patch for mdev-3851, that tried to weaken the condition when
a ref access with an extended key can be converted to an eq_ref
access. The patch incorrectly formed this condition. As a result,
while improving performance for some queries, the patch caused
worse performance for another queries.
The issue was that there was that SHOW commands could open the table in the store engine, even in cases
where it should not be allowed to do that (ie, the storage engines meta data for that table was under big changes).
The cases where this should not be allowed are:
- ALTER TABLE DISABLE KEYS
- ALTER TABLE ENABLE KEYS
- REPAIR TABLE
- OPTIMIZE TABLE
- DROP TABLE
This patch adds a new mode, protected_against_usage(). If this is used then the SHOW command will wait until the table
is accessable. This is implemented by re-using the already exising 'version' flag for TABLE_SHARE.
It also added functions to be used to change TABLE_SHARE->version instead of changing it directly.
mysql-test/r/myisam-metadata.result:
Added test case
mysql-test/t/myisam-metadata.test:
Added test case
sql/mysqld.cc:
Start from refresh_version 2 as 0 and 1 are reserved.
sql/sql_admin.cc:
Added MYSQL_OPEN_FOR_REPAIR
Updated call to wait_while_table_is_used()
sql/sql_base.cc:
Updated call to wait_while_table_is_used()
- Allow one to specify how the table should be removed (for all commands except show or for all commands).
- Don't allow one to reopen the table if one has called share->protect_against_usage()
sql/sql_base.h:
Added TDC_RT_REMOVE_NOT_OWN_AND_MARK_NOT_USABLE, which is used to mark that no one can reopen this table, except with MYSQL_OPEN_FOR_REPAIR .
- Added MYSQL_OPEN_FOR_REPAIR
- Updated prototype for wait_while_table_is_used()
sql/sql_table.cc:
Updated call to wait_while_table_is_used()
Use MYSQL_OPEN_FOR_REPAIR for open tables that where repaired.
sql/sql_truncate.cc:
Updated call to wait_while_table_is_used()
sql/table.cc:
Use set_refresh_version()
sql/table.h:
Added functions to be used to change TABLE_SHARE->version instead of changing it directly
Do not include BLOB fields into the key to access the temporary
table created for a materialized view/derived table.
BLOB components are not allowed in keys.
revid:georgi.kodinov@oracle.com-20120309130449-82e3bs5v3et1x0ef
committer: Georgi Kodinov <Georgi.Kodinov@Oracle.com>
timestamp: Fri 2012-03-09 15:04:49 +0200
message:
Bug #12408412: GROUP_CONCAT + ORDER BY + INPUT/OUTPUT SAME
USER VARIABLE = CRASH
Moved the preparation of the variables that receive the output from
SELECT INTO from execution time (JOIN:execute) to compile time
(JOIN::prepare). This ensures that if the same variable is used in the
SELECT part of SELECT INTO it will be properly marked as non-const
for this query.
Test case added.
Used proper fast iterator.
a better fix (much smaller and without regressions) is coming from 5.1
MySQL Bug #12408412: GROUP_CONCAT + ORDER BY + INPUT/OUTPUT SAME USER VARIABLE = CRASH
and
MySQL Bug#14664077 SEVERE PERFORMANCE DEGRADATION IN SOME CASES WHEN USER VARIABLES ARE USED
sql/item_func.cc:
don't use anything from Item_func_set_user_var::fix_fields()
in Item_func_set_user_var::save_item_result()
sql/sql_class.cc:
Call suv->save_item_result(item) *before* doing suv->fix_fields(), because
the former evaluates the item (and caches its value), while the latter marks
the user variable as non-const. The problem is that the item was fix_field'ed
when the user variable was const, and it doesn't expect it to change to non-const
in the middle of the execution.
mysys/errors.c:
revert upstream's fix. use a much simpler one
mysys/my_write.c:
revert upstream's fix. use a simpler one
sql/item_xmlfunc.cc:
useless, but ok
sql/mysqld.cc:
simplify upstream's fix
storage/heap/hp_delete.c:
remove upstream's fix.
we'll use a much less expensive approach.
The function remove_eq_cond removes the parts of a disjunction
for which it has been proved that they are always true. In the
result of this removal the disjunction may be converted into a
formula without OR that must be merged into the the AND formula
that contains the disjunction.
The merging of two AND conditions must take into account the
multiple equalities that may be part of each of them.
These multiple equality must be merged and become part of the
and object built as the result of the merge of the AND conditions.
Erroneously the function remove_eq_cond lacked the code that
would merge multiple equalities of the merged AND conditions.
This could lead to confusing situations when at the same AND
level there were two multiple equalities with common members
and the list of equal items contained only some of these
multiple equalities.
This, in its turn, could lead to an incorrect work of the
function substitute_for_best_equal_field when it tried to optimize
ref accesses. This resulted in forming invalid TABLE_REF objects
that were used to build look-up keys when materialized subqueries
were exploited.
This bug in the legacy code could manifest itself in queries with
semi-join materialized subqueries.
When a subquery is materialized all conditions that are imposed
only on the columns belonging to the tables from the subquery
are taken into account.The code responsible for subquery optimizations
that employes subquery materialization makes sure to remove these
conditions from the WHERE conditions of the query obtained after
it has transformed the original query into a query with a semi-join.
If the condition to be removed is an equality condition it could
be added to ON expressions and/or conditions from disjunctive branches
(parts of OR conditions) in an attempt to generate better access keys
to the tables of the query. Such equalities are supposed to be removed
later from all the formulas where they have been added to.
However, erroneously, this was not done in some cases when an ON
expression and/or a disjunctive part of the OR condition could
be converted into one multiple equality. As a result some equality
predicates over columns belonging to the tables of the materialized
subquery remained in the ON condition and/or the a disjunctive
part of the OR condition, and the excuter later, when trying to
evaluate them, returned wrong answers as the values of the fields
from these equalities were not valid.
This happened because any standalone multiple equality (a multiple
equality that are not ANDed with any other predicates) lacked
the information about equality predicates inherited from upper
levels (in particular, inherited from the WHERE condition).
The fix adds a reference to such information to any standalone
multiple equality.
The wrong result set returned by the left join query from
the bug test case happened due to several inconsistencies
and bugs of the legacy mysql code.
The bug test case uses an execution plan that employs a scan
of a materialized IN subquery from the WHERE condition.
When materializing such an IN- subquery the optimizer injects
additional equalities into the WHERE clause. These equalities
express the constraints imposed by the subquery predicate.
The injected equality of the query in the test case happens
to belong to the same equality class, and a new equality
imposing a condition on the rows of the materialized subquery
is inferred from this class. Simultaneously the multiple
equality is added to the ON expression of the LEFT JOIN
used in the main query.
The inferred equality of the form f1=f2 is taken into account
when optimizing the scan of the rows the temporary table
that is the result of the subquery materialization: only the
values of the field f1 are read from the table into the record
buffer. Meanwhile the inferred equality is removed from the
WHERE conditions altogether as a constraint on the fields
of the temporary table that has been used when filling this table.
This equality is supposed to be removed from the ON expression
when the multiple equalities of the ON expression are converted
into an optimal set of equality predicates. It supposed to be
removed from the ON expression as an equality inferred from only
equalities of the WHERE condition. Yet, it did not happened
due to the following bug in the code.
Erroneously the code tried to build multiple equality for ON
expression twice: the first time, when it called optimize_cond()
for the WHERE condition, the second time, when it called
this function for the HAVING condition. When executing
optimize_con() for the WHERE condition a reference
to the multiple equality of the WHERE condition is set
in the multiple equality of the ON expression. This reference
would allow later to convert multiple equalities of the
ON expression into equality predicates. However the
the second call of build_equal_items() for the ON expression
that happened when optimize_cond() was called for the
HAVING condition reset this reference to NULL.
This bug fix blocks calling build_equal_items() for ON
expressions for the second time. In general, it will be
beneficial for many queries as it removes from ON
expressions any equalities that are to be checked for the
WHERE condition.
The patch also fixes two bugs in the list manipulation
operations and a bug in the function
substitute_for_best_equal_field() that resulted
in passing wrong reference to the multiple equalities
of where conditions when processing multiple
equalities of ON expressions.
The code of substitute_for_best_equal_field() and
the code the helper function eliminate_item_equal()
were also streamlined and cleaned up.
Now the conversion of the multiple equalities into
an optimal set of equality predicates first produces
the sequence of the all equalities processing multiple
equalities one by one, and, only after this, it inserts
the equalities at the beginning of the other conditions.
The multiple changes in the output of EXPLAIN
EXTENDED are mainly the result of this streamlining,
but in some cases is the result of the removal of
unneeded equalities from ON expressions. In
some test cases this removal were reflected in the
output of EXPLAIN resulted in disappearance of
“Using where” in some rows of the execution plans.
Analysis:
Range analysis detects that the subquery is expensive and doesn't
build a range access method. Later, the applicability test for loose
scan doesn't take that into account, and builds a loose scan method
without a range scan on the min/max column. As a result loose scan
fetches the first key in each group, rather than the first key that
satisfies the condition on the min/max column.
Solution:
Since there is no SEL_ARG tree to be used for the min/max column,
it is not possible to use loose scan if the min/max column is compared
with an expensive scalar subquery. Make the test for loose scan
applicability to be in sync with the range analysis code by testing if
the min/max argument is compared with an expensive predicate.
This bug happened because the executor tried to use a wrong
TABLE REF object when building access keys. It constructed
keys from fields of a materialized table from a ref object
created to construct keys from the fields of the underlying
base table. This could happen only when materialized table
was created for a non-correlated IN subquery and only
when the materialized table used for lookups.
In this case we are guaranteed to be able to construct the
keys from the fields of tables that would be outer tables
for the tables of the IN subquery.
The patch makes sure that no ref objects constructed from
fields of materialized lookup tables are to be used.
Analys:
The cause for the wrong result was that the optimizer
incorrectly chose min/max loose scan when it is not
applicable. The applicability test missed the case when
a condition on the MIN/MAX argument was OR-ed with a
condition on some other field. In this case, the MIN/MAX
condition cannot be used for loose scan.
Solution:
Extend the test check_group_min_max_predicates() to check
that the WHERE clause is of the form: "cond1 AND cond2"
where
cond1 - does not use min_max_column at all.
cond2 - is an AND/OR tree with leaves in form "min_max_column $CMP$ const"
or $CMP$ is one of the functions between, is [not] null
Analysis:
Range analysis discoveres that the query can be executed via loose index scan for GROUP BY.
Later, GROUP BY analysis fails to confirm that the GROUP operation can be computed via an
index because there is no logic to handle duplicate field references in the GROUP clause.
As a result the optimizer produces an inconsistent plan. It constructs a temporary table,
but on the other hand the group fields are not set to point there.
Solution:
Make loose scan analysis work in sync with order by analysis. In the case of duplicate
columns loose scan will not be applicable. This limitation will be lifted in 10.0 by
removing duplicate columns.
from MariaDB 10.0.
The bug in mdev-3948 was an instance of the problem fixed by Sergey's patch
in 10.0 - namely that the range optimizer could change table->[read | write]_set,
and not restore it.
revno: 3471
committer: Sergey Petrunya <psergey@askmonty.org>
branch nick: 10.0-serg-fix-imerge
timestamp: Sat 2012-11-03 12:24:36 +0400
message:
# MDEV-3817: Wrong result with index_merge+index_merge_intersection, InnoDB table, join, AND and OR conditions
Reconcile the fixes from:
#
# guilhem.bichot@oracle.com-20110805143029-ywrzuz15uzgontr0
# Fix for BUG#12698916 - "JOIN QUERY GIVES WRONG RESULT AT 2ND EXEC. OR
# AFTER FLUSH TABLES [-INT VS NULL]"
#
# guilhem.bichot@oracle.com-20111209150650-tzx3ldzxe1yfwji6
# Fix for BUG#12912171 - ASSERTION FAILED: QUICK->HEAD->READ_SET == SAVE_READ_SET
# and
#
and related fixes from: BUG#1006164, MDEV-376:
Now, ROR-merged QUICK_RANGE_SELECT objects make no assumptions about the values
of table->read_set and table->write_set.
Each QUICK_ROR_SELECT has (and had before) its own column bitmap, but now, all
QUICK_ROR_SELECT's functions that care: reset(), init_ror_merged_scan(), and
get_next() will set table->read_set when invoked and restore it back to what
it was before the call before they return.
This allows to avoid the mess when somebody else modifies table->read_set for
some reason.
The problem was that a temporary table was re-created as a non-temporary table.
mysql-test/suite/maria/truncate.result:
Added test cases
mysql-test/suite/maria/truncate.test:
Added test cases
sql/sql_truncate.cc:
Mark that table to be created is a temporary table
storage/maria/ha_maria.cc:
Ensure that temporary tables are not transactional.
reached by fix_fields() (via reference) before row which it belongs to (on the second execution)
and fix_field for row did not follow usual protocol for Items with argument
(first check that the item fixed then call fix_fields).
Item_row::fix_field fixed.
allow only three failed change_user per connection.
successful change_user do NOT reset the counter
tests/mysql_client_test.c:
make --error to work for --change_user errors
