Fields belonging to views in general cannot be substituted for
equal items, in particular for constants, because all references
to a view field refer to the same Item_field object while they
could be used in different OR parts of the where condition and
belong to different equivalence classes (to different Item_equals).
That's why substitution for equal items in any context is allowed
only in place of Item_direct_view_ref objects, but not in place of
Item_fields these objects refer to.
Due to some erroneous code in the patch for bug 717577 substitution
for view fields were allowed in some context.This could lead
to wrong results returned by queries using views.
The fix prohibits substitution of view fields for equal items
in any context.
The patch also changes slightly the compile method for the Item_func
class. Now if the analyze method returns NULL in his parameter the
compile method is not called for the arguments of the function
at all. A similar change was made for the Item_ref class.
Both these two bugs happened due to the following problem.
When a view column is referenced in the query an Item_direct_view_ref
object is created that is refers to the Item_field for the column.
All references to the same view column refer to the same Item_field.
Different references can belong to different AND/OR levels and,
as a result, can be included in different Item_equal object.
These Item_equal objects may include different constant objects.
If these constant objects are substituted for the Item_field created
for a view column we have a conflict situation when the second
substitution annuls the first substitution. This leads to
wrong result sets returned by the query. Bug #724942 demonstrates
such an erroneous behaviour.
Test case of the bug #717577 produces wrong result sets because best
equal fields of the multiple equalities built for different OR levels
of the WHERE condition differs. The subsitution for the best equal field
in the second OR branch overwrites the the substitution made for the
first branch.
To avoid such conflicts we have to substitute for the references
to the view columns rather than for the underlying field items.
To make such substitutions possible we have to include into
multiple equalities references to view columns rather than
field items created for such columns.
This patch modifies the Item_equal class to include references
to view columns into multiple equality objects. It also performs
a clean up of the class methods and adds more comments. The methods
of the Item_direct_view_ref class that assist substitutions for
references to view columns has been also added by this patch.
Select from a view with the underlying HAVING clause failed with a
message: "1356: View '...' references invalid table(s) or column(s)
or function(s) or definer/invoker of view lack rights to use them"
The bug is a regression of the fix for bug 11750328 - 40825 (similar
case, but the HAVING cause references an aliased field).
In the old fix for bug 40825 the Item_field::name_length value has
been used in place of the real length of Item_field::name. However,
in some cases Item_field::name_length is not in sync with the
actual name length (TODO: combine name and name_length into a
solid String field).
The Item_ref::print() method has been modified to calculate actual
name length every time.
mysql-test/r/view.result:
Test case for bug #11829681
mysql-test/t/view.test:
Test case for bug #11829681
sql/item.cc:
Bug #11829681 - 60295: ERROR 1356 ON VIEW THAT EXECUTES FINE AS A QUERY
The Item_ref::print() method has been modified to calculate actual
name length every time.
sql/item.h:
Minor commentary.
- Fixed some issues with partitions and connection_string, which also fixed lp:716890 "Pre- and post-recovery crash in Aria"
- Fixed wrong assert in Aria
Now need to merge with latest xtradb before pushing
sql/ha_partition.cc:
Ensure that m_ordered_rec_buffer is not freed before close.
sql/mysqld.cc:
Changed to use opt_stack_trace instead of opt_pstack.
Removed references to pstack
sql/partition_element.h:
Ensure that connect_string is initialized
storage/maria/ma_key_recover.c:
Fixed wrong assert
with the test case added by this patch.
The bug cannot be reproduced with the same test case for the main
5.3 tree because the backported fix for bug 59696 masks the
problem that causes the crash in the mentioned test case. It's not
clear weather this fix masks this problem in all possible cases.
Anyway the patch for bug 698882 introduced some inconsistent data
structures that could contain indirect references to deleted object.
It happened when two Item_equal objects were merged and the Item_field
list of the second object was joined to such list of the first object.
This operation required adjustment of the backward pointers in
Item fields from the joined list. However the adjustment was missing
and this caused crashes in the tree for mwl#128.
Now the backward pointers are set only when Item_equal items are
completely built and are not changed anymore.
The patch fixed the following optimizer defect: when performing
substitution for best equal fields into where conditions to be
able to do their evaluations as soon as possible the optimizer
skipped conditions over views. That could lead to suboptimal
execution of queries that used views.
Slightly changed the test case to demonstrate the performance
improvements if this fix.
--Bug#52157 various crashes and assertions with multi-table update, stored function
--Bug#54475 improper error handling causes cascading crashing failures in innodb/ndb
--Bug#57703 create view cause Assertion failed: 0, file .\item_subselect.cc, line 846
--Bug#57352 valgrind warnings when creating view
--Recently discovered problem when a nested materialized derived table is used
before being populated and it leads to incorrect result
We have several modes when we should disable subquery evaluation.
The reasons for disabling are different. It could be
uselessness of the evaluation as in case of 'CREATE VIEW'
or 'PREPARE stmt', or we should disable subquery evaluation
if tables are not locked yet as it happens in bug#54475, or
too early evaluation of subqueries can lead to wrong result
as it happened in Bug#19077.
Main problem is that if subquery items are treated as const
they are evaluated in ::fix_fields(), ::fix_length_and_dec()
of the parental items as a lot of these methods have
Item::val_...() calls inside.
We have to make subqueries non-const to prevent unnecessary
subquery evaluation. At the moment we have different methods
for this. Here is a list of these modes:
1. PREPARE stmt;
We use UNCACHEABLE_PREPARE flag.
It is set during parsing in sql_parse.cc, mysql_new_select() for
each SELECT_LEX object and cleared at the end of PREPARE in
sql_prepare.cc, init_stmt_after_parse(). If this flag is set
subquery becomes non-const and evaluation does not happen.
2. CREATE|ALTER VIEW, SHOW CREATE VIEW, I_S tables which
process FRM files
We use LEX::view_prepare_mode field. We set it before
view preparation and check this flag in
::fix_fields(), ::fix_length_and_dec().
Some bugs are fixed using this approach,
some are not(Bug#57352, Bug#57703). The problem here is
that we have a lot of ::fix_fields(), ::fix_length_and_dec()
where we use Item::val_...() calls for const items.
3. Derived tables with subquery = wrong result(Bug19077)
The reason of this bug is too early subquery evaluation.
It was fixed by adding Item::with_subselect field
The check of this field in appropriate places prevents
const item evaluation if the item have subquery.
The fix for Bug19077 fixes only the problem with
convert_constant_item() function and does not cover
other places(::fix_fields(), ::fix_length_and_dec() again)
where subqueries could be evaluated.
Example:
CREATE TABLE t1 (i INT, j BIGINT);
INSERT INTO t1 VALUES (1, 2), (2, 2), (3, 2);
SELECT * FROM (SELECT MIN(i) FROM t1
WHERE j = SUBSTRING('12', (SELECT * FROM (SELECT MIN(j) FROM t1) t2))) t3;
DROP TABLE t1;
4. Derived tables with subquery where subquery
is evaluated before table locking(Bug#54475, Bug#52157)
Suggested solution is following:
-Introduce new field LEX::context_analysis_only with the following
possible flags:
#define CONTEXT_ANALYSIS_ONLY_PREPARE 1
#define CONTEXT_ANALYSIS_ONLY_VIEW 2
#define CONTEXT_ANALYSIS_ONLY_DERIVED 4
-Set/clean these flags when we perform
context analysis operation
-Item_subselect::const_item() returns
result depending on LEX::context_analysis_only.
If context_analysis_only is set then we return
FALSE that means that subquery is non-const.
As all subquery types are wrapped by Item_subselect
it allow as to make subquery non-const when
it's necessary.
mysql-test/r/derived.result:
test case
mysql-test/r/multi_update.result:
test case
mysql-test/r/view.result:
test case
mysql-test/suite/innodb/r/innodb_multi_update.result:
test case
mysql-test/suite/innodb/t/innodb_multi_update.test:
test case
mysql-test/suite/innodb_plugin/r/innodb_multi_update.result:
test case
mysql-test/suite/innodb_plugin/t/innodb_multi_update.test:
test case
mysql-test/t/derived.test:
test case
mysql-test/t/multi_update.test:
test case
mysql-test/t/view.test:
test case
sql/item.cc:
--removed unnecessary code
sql/item_cmpfunc.cc:
--removed unnecessary checks
--THD::is_context_analysis_only() is replaced with LEX::is_ps_or_view_context_analysis()
sql/item_func.cc:
--refactored context analysis checks
sql/item_row.cc:
--removed unnecessary checks
sql/item_subselect.cc:
--removed unnecessary code
--added DBUG_ASSERT into Item_subselect::exec()
which asserts that subquery execution can not happen
if LEX::context_analysis_only is set, i.e. at context
analysis stage.
--Item_subselect::const_item()
Return FALSE if LEX::context_analysis_only is set.
It prevents subquery evaluation in ::fix_fields &
::fix_length_and_dec at context analysis stage.
sql/item_subselect.h:
--removed unnecessary code
sql/mysql_priv.h:
--Added new set of flags.
sql/sql_class.h:
--removed unnecessary code
sql/sql_derived.cc:
--added LEX::context_analysis_only analysis intialization/cleanup
sql/sql_lex.cc:
--init LEX::context_analysis_only field
sql/sql_lex.h:
--New LEX::context_analysis_only field
sql/sql_parse.cc:
--removed unnecessary code
sql/sql_prepare.cc:
--removed unnecessary code
--added LEX::context_analysis_only analysis intialization/cleanup
sql/sql_select.cc:
--refactored context analysis checks
sql/sql_show.cc:
--added LEX::context_analysis_only analysis intialization/cleanup
sql/sql_view.cc:
--added LEX::context_analysis_only analysis intialization/cleanup
metadata"
Improved error handling such that queries against Information_Schema.Tables won't
fail if a federated table can't make a remote connection.
mysql-test/r/merge.result:
Updated with warnings that were previously masked.
mysql-test/r/show_check.result:
Updated with warnings that were previously masked.
mysql-test/r/view.result:
Updated with warnings that were previously masked.
sql/sql_show.cc:
If get_schema_tables_record() encounters an error, push a warning,
set the TABLE COMMENT column with the error text, and clear the
error so that the operation can continue.
Applied the fix for bug #47217 from the mysql-6.0 codebase.
The patch adds not null predicates generated for the left parts
of the equality predicates used for ref accesses. This is done
for such predicates both in where conditions and on conditions.
For the where conditions the not null predicates were generated
but in 5.0/5.1 they actually never were used due to some lame
merge from 4.1 to 5.0. The fix for bug #47217 made these
predicates to be used in the condition pushed to the tables.
Yet only this patch generates not null predicates for equality
predicated from on conditions of outer joins.
This patch introduces a performance regression that can be
observed on a test case from null_key.test. The regression
will disappear after the fix for bug #57024 from mariadb-5.1
is pulled into mariadb-5.3.
The patch contains many changes in the outputs of the EXPLAIN
commands since generated not null predicates are considered as
parts of the conditions pushed to join tables and may add
'Usingwhere' in some rows of EXPLAINs where there used
to be no such comments.
The problem could be demonstrated with an outer join of two single-row
tables where the values of the join attributes were null. Any query
with such a join could return a wrong result set if the where
condition of the query was not empty. For queries with empty
where conditions the result sets were correct.
This was the consequence of two bugs in the code:
- Item_equal objects for on conditions of outer joins were
not built if the processed query had no where condition
- the check for null values in the code that evaluated constant
Item_equal objects was incorrect.
Fixed both above problems.
Added a test case for the bug and adjusted results for some other
test cases.
Fixed some bugs introduced in 5.1.47
Disabled some tests until we have merged with latest Xtradb
configure.in:
Added testing if valgrind/memcheck.h exists
storage/pbxt/src/ha_pbxt.cc:
LOCK_plugin is not anymore locked in init
We should disable const subselect item evaluation because
subselect transformation does not happen in view_prepare_mode
and thus val_...() methods can not be called.
mysql-test/r/ctype_ucs.result:
test case
mysql-test/r/view.result:
test case
mysql-test/t/ctype_ucs.test:
test case
mysql-test/t/view.test:
test case
sql/item.cc:
disabled const subselect item evaluation in
view prepare mode.
sql/item_subselect.cc:
added Item_subselect::safe_charset_converter which
prevents const item evaluation in view prepare mode.
sql/item_subselect.h:
added Item_subselect::safe_charset_converter which
prevents const item evaluation in view prepare mode.
The problem is that not all column names retrieved from a SELECT
statement can be used as view column names due to length and format
restrictions. The server failed to properly check the conformity
of those automatically generated column names before storing the
final view definition on disk.
Since columns retrieved from a SELECT statement can be anything
ranging from functions to constants values of any format and length,
the solution is to rewrite to a pre-defined format any names that
are not acceptable as a view column name.
The name is rewritten to "Name_exp_%u" where %u translates to the
position of the column. To avoid this conversion scheme, define
explict names for the view columns via the column_list clause.
Also, aliases are now only generated for top level statements.
mysql-test/include/view_alias.inc:
Add test case for Bug#40277
mysql-test/r/compare.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/group_by.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/ps.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/subselect.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/subselect3.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/type_datetime.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/union.result:
Bug#40277: SHOW CREATE VIEW returns invalid SQL
mysql-test/r/view.result:
Add test case result for Bug#40277
mysql-test/r/view_alias.result:
Add test case result for Bug#40277
mysql-test/t/view_alias.test:
Add test case for Bug#40277
sql/sql_view.cc:
Check if auto generated column names are conforming. Also, the
make_unique_view_field_name function is not used as it uses the
original name to construct a new one, which does not work if the
name is invalid.
myisam-recover options changed from OFF to 'DEFAULT' to get less change of data loss when using MyISAM.
(The disadvantage is that changed MyISAM tables will be checked at access time; Use --myisam-recover=OFF for old behavior)
Don't call extra(HA_EXTRA_FORCE_REOPEN) in ALTER TABLE if table is locked as this will mark table as crashed!
Added assert to detect if we accidently would use MyISAM versioning in MySQL
include/my_base.h:
Mark NOT_USED as USED, as we now use this as a flag to not call extra()
mysql-test/mysql-test-run.pl:
Don't write all options when there is something wrong with the arguments
mysql-test/r/sp-destruct.result:
Add missing flush of mysql.proc (as the test copied live tables)
mysql-test/r/variables.result:
myisam-recover options changed to 'default'
mysql-test/r/view.result:
Don't show create time in result
mysql-test/suite/maria/t/maria-recovery2-master.opt:
Don't run test with myisam-recover (as this produces extra warnings during simulated death)
mysql-test/t/sp-destruct.test:
Add missing flush of mysql.proc (as the test copied live tables)
mysql-test/t/view.test:
Don't show create time in result
sql/lock.cc:
Added marker if table was deleted to argument list
sql/mysql_priv.h:
Added marker if table was deleted to argument list
sql/mysqld.cc:
myisam-recover options changed from OFF to 'DEFAULT' to get less change of data loss when using MyISAM
Allow one to specify OFF as argument to myisam-recover (was default before but one couldn't specify it)
sql/sql_base.cc:
Mark if table is going to be deleted
sql/sql_delete.cc:
Mark if table is going to be deleted
sql/sql_table.cc:
Mark if table is going to be deleted
Don't call extra(HA_EXTRA_FORCE_REOPEN) in ALTER TABLE if table is locked as this will mark table as crashed!
sql/table.cc:
Signal to handler if table is getting deleted as part of getting droped from table cache.
sql/table.h:
Added marker if table is going to be deleted.
storage/maria/ha_maria.cc:
Don't search for transaction handler if file is not transactional or outside of transaction
(Fixed possible core dump)
storage/maria/ma_blockrec.c:
Don't write changed information if table is going to be deleted.
storage/maria/ma_close.c:
Don't write changed information if table is going to be deleted.
storage/maria/ma_extra.c:
Mark tables that are deleted as crased, to ensure good behavior on restart if we suddenly crash.
storage/maria/ma_locking.c:
Cleanup
storage/maria/ma_recovery.c:
We need trnman to be inited during redo phase (to be able to open tables checked with maria_chk)
storage/maria/maria_def.h:
Added marker if table is going to be deleted.
storage/myisam/mi_close.c:
Don't write changed information if table is going to be deleted.
storage/myisam/mi_extra.c:
Mark tables that are deleted as crased, to ensure good behavior on restart if we suddenly crash.
storage/myisam/mi_open.c:
Added assert to detect if we accidently would use MyISAM versioning in MySQL
storage/myisam/myisamdef.h:
Added marker if table is going to be deleted.
In case of 'CREATE VIEW' subselect transformation does not happen(see JOIN::prepare).
During fix_fields Item_row may call is_null() method for its arugmens which
leads to item calculation(wrong subselect in our case as
transformation did not happen before). This is_null() call
does not make sence for 'CREATE VIEW'.
Note:
Only Item_row is affected because other items don't call is_null()
during fix_fields() for arguments.
mysql-test/r/view.result:
test case
mysql-test/t/view.test:
test case
sql/item_row.cc:
skip is_null() call in case of 'CREATE VIEW' as unnecessary.
SHOW CREATE TABLE on a view (v1) that contains a function whose
statement uses another view (v2), could trigger a infinite loop
if the view referenced within the function causes a warning to
be raised while opening the said view (v2).
The problem was a infinite loop over the stack of internal error
handlers. The problem would be triggered if the stack contained
two or more handlers and the first two handlers didn't handle the
raised condition. In this case, the loop variable would always
point to the second handler in the stack.
The solution is to correct the loop variable assignment so that
the loop is able to iterate over all handlers in the stack.
mysql-test/r/view.result:
Add test case result for Bug#48449.
mysql-test/std_data/bug48449.frm:
Add a incomplete view definition that causes a warning to be
issued.
mysql-test/t/view.test:
Add test case for Bug#48449
sql/sql_class.cc:
Iterate over all handlers in the stack.
The problem was that a failure to open a view wasn't being
properly handled. When opening a view with unknown definer,
the open procedure would be treated as successful and would
later crash when attempting to lock the view (which wasn't
opened to begin with).
The solution is to skip further processing when opening a
table if it fails with a fatal error.
mysql-test/r/view.result:
Add test case result for Bug#47734.
mysql-test/t/view.test:
Add test case for Bug#47734.
sql/sql_base.cc:
Skip further processing if opening a table failed due to
a fatal error (for the statement).
WL#2474 "Multi Range Read: Change the default MRR implementation to implement new MRR interface"
WL#2475 "Batched range read functions for MyISAM/InnoDb"
"Index condition pushdown for MyISAM/InnoDB"
Igor's fix from sp1r-igor@olga.mysql.com-20080330055902-07614:
There could be observed the following problems:
1. EXPLAIN did not mention pushdown conditions from on expressions in the
'extra' column. As a result if a query had no where conditions pushed
down to a table, but had on conditions pushed to this table the 'extra'
column in the EXPLAIN for the table missed 'using where'.
2. Conditions for ref access were not eliminated from on expressions
though such conditions were eliminated from the where condition.
> ------------------------------------------------------------
> revno: 2792
> revision-id: sergey.glukhov@sun.com-20090703083500-jq8vhw0tqr37j7te
> parent: bernt.johnsen@sun.com-20090703083610-o7l4s8syz05rc4w0
> committer: Sergey Glukhov <Sergey.Glukhov@sun.com>
> branch nick: mysql-5.0-bugteam
> timestamp: Fri 2009-07-03 13:35:00 +0500
> message:
> Bug#45806 crash when replacing into a view with a join!
> The crash happend because for views which are joins
> we have table_list->table == 0 and
> table_list->table->'any method' call leads to crash.
> The fix is to perform table_list->table->file->extra()
> method for all tables belonging to view.
The crash happend because for views which are joins
we have table_list->table == 0 and
table_list->table->'any method' call leads to crash.
The fix is to perform table_list->table->file->extra()
method for all tables belonging to view.
mysql-test/r/view.result:
test result
mysql-test/t/view.test:
test case
sql/sql_insert.cc:
added prepare_for_positional_update() function
which updates extra info about primary key for
tables belonging to view.
with a "HAVING" clause though query works
SELECT from views defined like:
CREATE VIEW v1 (view_column)
AS SELECT c AS alias FROM t1 HAVING alias
fails with an error 1356:
View '...' references invalid table(s) or column(s)
or function(s) or definer/invoker of view lack rights
to use them
CREATE VIEW form with a (column list) substitutes
SELECT column names/aliases with names from a
view column list.
However, alias references in HAVING clause was
not substituted.
The Item_ref::print function has been modified
to write correct aliased names of underlying
items into VIEW definition generation/.frm file.
mysql-test/r/view.result:
Added test file for bug #40825.
mysql-test/t/view.test:
Added test file for bug #40825.
sql/item.cc:
Bug#40825: Error 1356 while selecting from a view
with a "HAVING" clause though query works
The Item_ref::print function has been modified
to write correct aliased names of underlying
items into VIEW definition generation/.frm file.
Problem: executing queries like "ALTER TABLE view1;" we don't
check new view's name (which is not specified),
that leads to server crash.
Fix: do nothing (to be consistent with the behaviour for tables)
in such cases.
mysql-test/r/view.result:
Fix for bug#44860: ALTER TABLE on view crashes server
- test result.
mysql-test/t/view.test:
Fix for bug#44860: ALTER TABLE on view crashes server
- test case.
sql/sql_rename.cc:
Fix for bug#44860: ALTER TABLE on view crashes server
- do_rename(): new view/table name must be specified, ASSERT() added.
sql/sql_table.cc:
Fix for bug#44860: ALTER TABLE on view crashes server
- mysql_alter_table(): renaming a view, check if new
view name is specified.
+ Fix for Bug#43114 wait_until_count_sessions too restrictive, random PB failures
+ Removal of a lot of other weaknesses found
+ modifications according to review
an error
Even after the fix for bug 28701 visible behaviors of
SELECT FROM a view and SELECT FROM a regular table are
little bit different:
1. "SELECT FROM regular table USE/FORCE/IGNORE(non
existent index)" fails with a "ERROR 1176 (HY000):
Key '...' doesn't exist in table '...'"
2. "SELECT FROM view USING/FORCE/IGNORE(any index)" fails
with a "ERROR 1221 (HY000): Incorrect usage of
USE/IGNORE INDEX and VIEW". OTOH "SHOW INDEX FROM
view" always returns empty result set, so from the point
of same behaviour view we trying to use/ignore non
existent index.
To harmonize the behaviour of USE/FORCE/IGNORE(index)
clauses in SELECT from a view and from a regular table the
"ERROR 1221 (HY000): Incorrect usage of USE/IGNORE INDEX
and VIEW" message has been replaced with the "ERROR 1176
(HY000): Key '...' doesn't exist in table '...'" message
like for tables and non existent keys.
mysql-test/r/view.result:
Added test case for bug #33461.
Updated test case for bug 28701.
mysql-test/t/view.test:
Added test case for bug #33461.
Updated test case for bug 28701.
sql/sql_view.cc:
Bug #33461: SELECT ... FROM <view> USE INDEX (...) throws
an error
To harmonize the behaviour of USE/FORCE/IGNORE(index)
clauses in SELECT from a view and from a regular table the
"ERROR 1221 (HY000): Incorrect usage of USE/IGNORE INDEX
and VIEW" message has been replaced with the "ERROR 1176
(HY000): Key '...' doesn't exist in table '...'" message
like for tables and non existent keys.
A string buffers which were included in the 'view' data structure
were allocated on the stack, causing an invalid pointer when used
after the function returned.
The fix: use copy of values for view->md5 & view->queries
mysql-test/r/view.result:
test result
mysql-test/t/view.test:
test case
sql/sql_view.cc:
A string buffers which were included in the 'view' data structure
were allocated on the stack, causing an invalid pointer when used
after the function returned.
The fix: use copy of values for view->md5 & view->queries
