There is no reason for it to be readonly at runtime and it is dynamic in
5.6+ already.

row0ins.c:1437:6: error: ISO C90 forbids mixed declarations and code [-Werror=declaration-after-statement]
enum wsrep_key_type key_type = WSREP_KEY_EXCLUSIVE;
^

This is used for controlling whether to use a new/optimized
certification rules or the old/classic ones that could cause more
certification failures - when foreign keys are used and two INSERTs are
done concurrently to the child table from different nodes.

(cherry picked from commit 815d73e6af8daace6262ab63ca6c043ffc4204b3)

wsrep_append_foreign_key() and wsrep_append_key() used to take a boolean
argument denoting whether the relevant certification key type is shared
(assuming it is exclusive if the argument is false). Change that
argument to the enum wsrep_key_type from wsrep_api.h, so that eventually
other types can also be passed (like WSREP_KEY_SEMI).

This is a non-functional change.

(cherry picked from commit 360bf36dbb9378b36ef57921c725a9505e19e0d9)

MDEV-13129: apport - sanitize wsrep_sst_auth from report

Fix misplaced `DBUG_RETURN` in `Alter_table_statement::execute`.

Adding a FK constraint to an existing table (ALTER TABLE ADD FOREIGN
KEY) causes the applier to fail, if a concurrent DML statement that
violate the new constraint (i.e. a DELETE or UPDATE of record in the
parent table).

For exmaple, the following scenario causes a crash in the applier:

1. ALTER successfully adds FK constraint in node_1
2. On node_2 is UPDATE is in pre_commit() and has certified successfully
3. ALTER is delivered in node_2 and BF aborts DML
4. Applying UPDATE event causes FK violation in node_1

To avoid this situation it is necessary for UPDATE to fail during
certification. And for the UPDATE to fail certfication it is necessary
that ALTER appends certification keys for both the child and the parent
table. Before this patch, ALTER TABLE ADD FK only appended keys for
child table which is ALTERed.

No commit message

We do not accept:
1. We did not have this problem (fixed earlier and better)
 d982e717 Bug#27510150: MYSQLDUMP FAILS FOR SPECIFIC --WHERE CLAUSES
2. We do not have such options (an DBUG_ASSERT put just in case)
 bbc2e37f Bug#27759871: BACKRONYM ISSUE IS STILL IN MYSQL 5.7
3. Serg fixed it in other way in this release:
 e48d775c Bug#27980823: HEAP OVERFLOW VULNERABILITIES IN MYSQL CLIENT LIBRARY

In this case we are setting the field Item_func_eq::in_eqaulity_no for the semi-join equalities.
This helps us to remove these equalites as the inner tables are not available during parent select execution
while the outer tables are not available during materialization phase.
We only have it set for the equalites for the fields involved with the IN subquery
and reset it for the equalities which do not belong to the IN subquery.

For example in case of nested IN subqueries:

    SELECT t1.a FROM t1 WHERE t1.a IN
      (SELECT t2.a FROM t2 where t2.b IN
          (select t3.b from t3 where t3.c=27 ))

there are two equalites involving the fields of the IN subquery

1) t2.b = t3.b :  the field Item_func_eq::in_eqaulity_no is set when we merge the grandchild select into the child select
2) t1.a = t2.a :  the field Item_func_eq::in_eqaulity_no is set when we merge the child select into the parent select

But when we perform case 2) we should ensure that we reset the equalities in the child's WHERE clause.

MDEV-16751: Server crashes in st_join_table::cleanup or TABLE_LIST::is_with_table_recursive_reference
            with join_cache_level>2

During muliple equality propagation for a query in which we have an IN subquery, the items in the select list of the
subquery may not be part of the multiple equality because there might be another occurence of the same field in the
where clause of the subquery.
So we keyuse_is_valid_for_access_in_chosen_plan function which expects the items in the select list of the subquery to
be same to the ones in the multiple equality (through these multiple equalities we create keyuse array).
The solution would be that we expect the same field not the same Item because when we have SEMI JOIN MATERIALIZATION SCAN,
we use copy back technique to copies back the materialised table fields to the original fields of the base tables.

This patch fixes another problem introduced by the patch for mdev-4817.
The latter changed Item_cond::fix_fields() in such a way that it could
call the virtual method is_expensive(). With the first its call
the method saves the result in Item::is_expensive_cache. For all next
calls the method returns the result from this cache. So if the item
once was determined as expensive the method always returns true.
For subqueries it's not good, because non-optimized subqueries always
is considered as expensive.
It means that the cache should be invalidated after the call of
optimize_constant_subqueries().

Due to a legacy bug in the code of make_join_statistics() detecting
so-called constant tables could miss some of them in rare queries
that used RIGHT JOIN. As a result these queries had execution plans
different from the execution plans of the equivalent queries with
LEFT JOIN.
Besides starting from 10.2 this could trigger an assertion failure.

Closes #551

fix_semijoin_strategies_for_picked_join_order() should set
join->sjm_lookup_tables to be a bitmap of tables inside
SJ-Materialization-Lookup nests.

In this issue we are using derived_with_keys optimization and we are using these keys to do a hash join which is incorrect.
We cannot create keys for dervied tables whose keyparts have types are of BLOB or TEXT type. TEXT or BLOB  columns can only be
indexed over a specified length.

When the definition of the index used for hash join was created
in create_hj_key_for_table() it could cause memory overwrite
due to a bug that led to an underestimation of the number of
the index component.

For the purpose of reporting an error to error log, shutdown thread was
attempting to access current_thd->variables.lc_messages->errmsgs->errmsgs.
Whereas current_thd was NULL.

We should log errors according to global lc_messages setting instead of
session setting.

MDEV-16512 Server crashes in find_field_in_table_ref on 2nd
execution of SP referring to non-existing field

Problem was in the natural join code that it changed TABLE_LIST and
Item_fields but didn't restore changed things if things goes wrong
and was not able to re-execute after failure.
Some of the problems could have been avoided if we would have run
fix_fields before doing natural join transformations.

Fixed by marking functions complete AFTER they had executed, instead at
start.
I had also to change some tests that checked if Item_fields are usable.

This doesn't fix all known problems, but at least avoids some crashes.
What should be done in the near future is to mark the statement in the SP
as 'not re-executable' and force a reparse of it on next execution.

Reviewer: Sergei Petrunia <psergey@askmonty.org>

This reverts commit d39629f0.

Because running mtr for many hours with no output whatsoever
is not really what we should do.

And in 5.5 `make test` just works anyway, nothing to fix here.

MDEV-16534 PPC64: Unexpected error with a negative value into auto-increment columns in HEAP, MyISAM, ARIA

(cherry picked from commit b5b986b2cbd9a7848dc3f48e5c42b6d4e1e5fb22)

Added unregistering writers in case of log error.
Added more debugging control about adding/removing writers to the buffers.

           SELECT .. LIMIT 0 (new variant)

This is another attempt to fix the problem of mdev-14515.

update table->pos_in_table_list during prepare,
just like it's done in normal execution.

otherwise it'll be a dangling pointer

adjust tests

rewrite tautological engine descriptions

The order of outputting stored procedures is important. Stored
procedures must be available on view creation, for views which make use
of them. Make sure to print them before outputting tables.

Undo the revert that happened by mystake in commit 7fca4b50.