Make differentiation between pullout for merge and pulout of outer field during exists2in transformation.
In last case the field was outer and so we can safely start from name resolution context of the SELECT where it was pulled.
Old behavior lead to inconsistence between list of tables and outer name resolution context (which skips one SELECT for merge purposes) which creates problem vor name resolution.
As a result of this merge the code for the following tasks appears in 10.3:
- MDEV-12172 Implement tables specified by table value constructors
- MDEV-12176 Transform [NOT] IN predicate with long list of values INTO
[NOT] IN subquery.
Side effect: the second debug Note in cache_temporal_4265.result disappeared.
Before this change:
- During JOIN::cache_const_exprs(),
Item::get_cache() for Item_date_add_interval() was called.
The data type for date_add('2001-01-01',interval 5 day) is VARCHAR,
because the first argument is VARCHAR (not temporal).
Item_get_cache() created Item_cache_str('2001-01-06').
- During evaluate_join_record(), get_datetime_value() was called,
which called Item::get_date() for Item_cache_str('2001-01-06').
This gave the second Note. Then, get_datetime_value() created
a new cache, now Item_cache_temporal for '2001-01-06', so not
further str_to_datetime() happened.
After this change:
- During tem_bool_rowready_func2::fix_length_and_dec(),
Arg_comparator::set_cmp_func_datetime() is called,
which immediately creates an instance of Item_cache_date for
the result of date_add('2001-01-01',interval 5 day).
So later no str_to_datetime happens any more,
neither during JOIN::cache_const_exprs(),
nor during evaluate_join_record().
- Renaming sp_rcontext::sp to sp_rcontext:m_sp for consistency
with other sp_rcontext_members, and for consistency with the
same purpose member Item_sp_variable::m_sp.
- Passing a "const sp_head*" pointer to sp_rcontext::sp_rcontext()
and to sp_rcontext::create().
Initializing sp_rcontext::m_sp right in the constructor
instead of having a separate initialization after "new sp_rcontext"
or sp_rcontext::create().
- Adding the "const" qualifier to sp_rcontext::m_sp and Item_sp_variable::m_sp
Some innobase/xtrabackup changes around from 10.1 are null merged
, in partucular using os_set_file_size to extend tablespaces in server
or mariabackup.
They require non-trivial amount of additional work in 10.2, due to
innobase differences between 10.1 and 10.2
Fixing the data type for the "fuzzydate" parameter to
Item_func_hybrid_field_type::date_op() from uint to ulonglong,
for consistency with Item::get_date().
Changing datatypes for:
- Item_spvar_args::m_table
- sp_rcontext::m_var_table
- return value of create_virtual_tmp_table()
from TABLE* to Virtual_tmp_table*
Advantages:
- Stricter data type control
- Removing the duplicate code (a loop with free_blobs)
from destructors ~sp_rcontext() and ~Item_spvar_args(),
using "delete m_(var_)table" in both instead.
- Using Virtual_tmp_table::delete makes the code call Field::delete,
which calls TRASH() for the freed fields,
which is good for valgrind test runs.
- Implementing stricter data type control for Item_long_func descendants
- Cleanup: renaming Type_handler::can_return_str_ascii() to can_return_text()
(a better name).
- Fix win64 pointer truncation warnings
(usually coming from misusing 0x%lx and long cast in DBUG)
- Also fix printf-format warnings
Make the above mentioned warnings fatal.
- fix pthread_join on Windows to set return value.
This should also fix the MariaDB 10.2.2 bug
MDEV-13826 CREATE FULLTEXT INDEX on encrypted table fails.
MDEV-12634 FIXME: Modify innodb-index-online, innodb-table-online
so that they will write and read merge sort files. InnoDB 5.7
introduced some optimizations to avoid using the files for small tables.
Many collation test results have been adjusted for MDEV-10191.
The problem was introduced by the patch for MDEV-7661,
which (in addition to the fix itself) included an attempt to make
CONVERT/CAST work in the same way with fields
(i.e. return NULL in strict mode if a non-convertable character found).
It appeared to be a bad idea and some users were affected by this
behavior change. Changing CONVERT/CAST not depend on sql_mode
(restoring pre-10.1.4 behavior).
COL), NAME_CONST('NAME', NULL))
Backport of Bug#19143243 fix.
NAME_CONST item can return NULL_ITEM type in case of incorrect arguments.
NULL_ITEM has special processing in Item_func_in function.
In Item_func_in::fix_length_and_dec an array of possible comparators is
created. Since NAME_CONST function has NULL_ITEM type, corresponding
array element is empty. Then NAME_CONST is wrapped to ITEM_CACHE.
ITEM_CACHE can not return proper type(NULL_ITEM) in Item_func_in::val_int(),
so the NULL_ITEM is attempted compared with an empty comparator.
The fix is to disable the caching of Item_name_const item.
If compiling a non DBUG binary with
-DDBUG_ASSERT_AS_PRINTF asserts will be
changed to printf + stack trace (of stack
trace are enabled).
- Changed #ifndef DBUG_OFF to
#ifdef DBUG_ASSERT_EXISTS
for those DBUG_OFF that was just used to enable
assert
- Assert checking that could greatly impact
performance where changed to DBUG_ASSERT_SLOW which
is not affected by DBUG_ASSERT_AS_PRINTF
- Added one extra option to my_print_stacktrace() to
get more silent in case of stack trace printing as
part of assert.
"Optimization for equi-joins of derived tables with GROUP BY"
should be considered rather as a 'proof of concept'.
The task itself is targeted at an optimization that employs re-writing
equi-joins with grouping derived tables / views into lateral
derived tables. Here's an example of such transformation:
select t1.a,t.max,t.min
from t1 [left] join
(select a, max(t2.b) max, min(t2.b) min from t2
group by t2.a) as t
on t1.a=t.a;
=>
select t1.a,tl.max,tl.min
from t1 [left] join
lateral (select a, max(t2.b) max, min(t2.b) min from t2
where t1.a=t2.a) as t
on 1=1;
The transformation pushes the equi-join condition t1.a=t.a into the
derived table making it dependent on table t1. It means that for
every row from t1 a new derived table must be filled out. However
the size of any of these derived tables is just a fraction of the
original derived table t. One could say that transformation 'splits'
the rows used for the GROUP BY operation into separate groups
performing aggregation for a group only in the case when there is
a match for the current row of t1.
Apparently the transformation may produce a query with a better
performance only in the case when
- the GROUP BY list refers only to fields returned by the derived table
- there is an index I on one of the tables T used in FROM list of
the specification of the derived table whose prefix covers the
the fields from the proper beginning of the GROUP BY list or
fields that are equal to those fields.
Whether the result of the re-writing can be executed faster depends
on many factors:
- the size of the original derived table
- the size of the table T
- whether the index I is clustering for table T
- whether the index I fully covers the GROUP BY list.
This patch only tries to improve the chosen execution plan using
this transformation. It tries to do it only when the chosen
plan reaches the derived table by a key whose prefix covers
all the fields of the derived table produced by the fields of
the table T from the GROUP BY list.
The code of the patch does not evaluates the cost of the improved
plan. If certain conditions are met the transformation is applied.
