When there is no bounds on the upper or lower part of the window,
it doesn't matter if the type is numeric.
It also doesn't matter how many ORDER BY items there are in the
query.
Reviewers: Sergei Petrunia and Oleg Smirnov
This bug could affect queries containing a join of derived tables over
grouping views such that one of the derived tables contains a window
function while another uses view V with dependent subquery DSQ containing
a set function aggregated outside of the subquery in the view V. The
subquery also refers to the fields from the group clause of the view.Due to
this bug execution of such queries could produce wrong result sets.
When the fix_fields() method performs context analysis of a set function AF
first, at the very beginning the function Item_sum::init_sum_func_check()
is called. The function copies the pointer to the embedding set function,
if any, stored in THD::LEX::in_sum_func into the corresponding field of the
set function AF simultaneously changing the value of THD::LEX::in_sum_func
to point to AF. When at the very end of the fix_fields() method the function
Item_sum::check_sum_func() is called it is supposed to restore the value
of THD::LEX::in_sum_func to point to the embedding set function. And in
fact Item_sum::check_sum_func() did it, but only for regular set functions,
not for those used in window functions. As a result after the context
analysis of AF had finished THD::LEX::in_sum_func still pointed to AF.
It confused the further context analysis. In particular it led to wrong
resolution of Item_outer_ref objects in the fix_inner_refs() function.
This wrong resolution forced reading the values of grouping fields referred
in DSQ not from the temporary table used for aggregation from which they
were supposed to be read, but from the table used as the source table for
aggregation.
This patch guarantees that the value of THD::LEX::in_sum_func is properly
restored after the call of fix_fields() for any set function.
Crash was caused by referencing a null pointer on getting
the number of the nesting levels of the set function for the current
select_lex at the method Item_field::fix_fields.
The current select for processing is taken from Name_resolution_context
that filled in at the function set_new_item_local_context() and
where initialization of the data member Name_resolution_context
was mistakenly removed by the commit
d6ee351bbb
(Revert "MDEV-24454 Crash at change_item_tree")
To fix the issue, correct initialization of data member
Name_resolution_context::select_lex
that was removed by the commit d6ee351bbb
is restored.
This patch adds for "--ps-protocol" second execution
of queries "SELECT".
Also in this patch it is added ability to disable/enable
(--disable_ps2_protocol/--enable_ps2_protocol) second
execution for "--ps-prototocol" in testcases.
(Initial patch by Varun Gupta. Amended and added comments).
When the query has both
1. Aggregate functions that require sorting data by group, and
2. Window functions
we need to use two temporary tables. The first temp.table will hold the
join output. Then it is passed to filesort(). Reading it in sorted
order allows to compute the aggregate functions.
Then, we need to write their values into the second temp. table. Then,
Window Function computation step can pass that to filesort() and read
them in the order it needs.
Failure to create the second temp. table would cause an assertion
failure: window function could would not find where to get the values
of the aggregate functions.
Tests with checking metadata or that cannot be run with
the view-protocol are excluded from --view-protocol.
For tests that do not allow the use of an additional connection,
the util connection is disabled with "--disable_service_connection".
Also cases with bugs for --view-protocol are disabled.
