cleanup. use "command -v" instead of "which"
simplify some checks.

For placement new, throw() exception specification was removed by
accident in 8fe04a3d , making  debug
tests, that simulate out-of-memory situations, fail (e.g filesort_debug)

Correctly initialize fake IPs.

innobase_add_instant_try(): If the leftmost leaf page does not contain
other records than the 'default row', only empty the table if there
are no successor pages.

When a table or partition which was not empty during a previous
instant ADD COLUMN became empty later, and now with this subsequent
instant ADD COLUMN we have the opportunity to convert the empty table
or partition to 'non-instant' format.

Similarly, if the table or partition is empty to begin with, that is,
it does not even contain a 'default row' record, we can use the
'non-instant' format.

Until now, InnoDB inefficiently compared the aligned fields
FIL_PAGE_PREV, FIL_PAGE_NEXT to the byte-order-agnostic value FIL_NULL.

Timing problem as sometimes table is marked as encrypted but
sometimes we are not sure and table is just marked missing.

Compiler optimizations were switched off due to
MySQL Bug #19424, #36366, #34297, due to an alleged compiler bug.
No  proper analysis of code generation was done back then, thus proof of
a compiler bug is missing.

Even if there was a compiler bug 13 years ago, it could have been fixed.
Will wait and see if there are any complains or crashes

trx_undo_rec_copy(): Use a debug assertion. In a non-debug build,
with len<0 (which this assertion is really testing for)
we should still typically crash due to running out of memory.

Replace all occurrences of the is_clust() method with is_primary(),
because that is what is actually meant. (Also the change buffer
tree would count as a clustered index.)

Rollback attempted to dereference DB_ROLL_PTR=0, which cannot possibly
be a valid undo log pointer. A safer canonical value would be
roll_ptr_t(1) << ROLL_PTR_INSERT_FLAG_POS
which is what was chosen in MDEV-12288, corresponding to reset_trx_id.

No deterministic test case for the bug was found. The simplest test
cases may be related to MDEV-11415, which suppresses undo logging for
ALGORITHM=COPY operations. In those operations, in the spirit of
MDEV-12288, we should actually have written reset_trx_id instead of
using the transaction identifier of the current transaction
(and a bogus value of DB_ROLL_PTR=0). However, thanks to MySQL Bug#28432
which I had fixed in MySQL 5.6.8 as part of WL#6255, access to the
rebuilt table by earlier-started transactions should actually have been
refused with ER_TABLE_DEF_CHANGED.

reset_trx_id: Move the definition to data0type.cc and the declaration
to data0type.h.

btr_cur_ins_lock_and_undo(): When undo logging is disabled, use the
safe value that corresponds to reset_trx_id.

btr_cur_optimistic_insert(): Validate the DB_TRX_ID,DB_ROLL_PTR before
inserting into a clustered index leaf page.

ins_node_t::sys_buf[]: Replaces row_id_buf and trx_id_buf and some
heap usage.

row_ins_alloc_sys_fields(): Init ins_node_t::sys_buf[] to reset_trx_id.

row_ins_buf(): Only if undo logging is enabled, copy trx->id
to node->sys_buf. Otherwise, rely on the initialization in
row_ins_alloc_sys_fields().

row_purge_reset_trx_id(): Invoke mlog_write_string() with reset_trx_id
directly. (No functional change.)

trx_undo_page_report_modify(): Assert that the DB_ROLL_PTR is not 0.

trx_undo_get_undo_rec_low(): Assert that the roll_ptr is valid before
trying to dereference it.

dict_index_t::is_primary(): Check if the index is the primary key.

PageConverter::adjust_cluster_record(): Fix
MDEV-15249 Crash in MVCC read after IMPORT TABLESPACE
by resetting the system fields to reset_trx_id instead of writing
the current transaction ID (which will be committed at the
end of the IMPORT TABLESPACE) and DB_ROLL_PTR=0.
This can partially be viewed as a follow-up fix of MDEV-12288,
because IMPORT should already then have written
DB_TRX_ID=0 and DB_ROLL_PTR=1<<55 to prevent unnecessary
DB_TRX_ID lookups in subsequent accesses to the table.

fix a couple "initialization skipped by goto" and other new errors.

no matching operator delete found; memory will not be freed if initialization throws an exception

Added a no-op delete() for MEM_ROOT based placement-new()

But set _CRT_NONSTDC_NO_WARNINGS to silence silly warnings about
ANSI C function being non-standard

Remove now deprecated GetVersion()/GetVersionEx(),except single case
where where it is really needed, in feedback plugin. Remove checks for
Windows NT.

Avoid old IPv4-only inet_aton, which generated the warning.

The test was used to result in mismatch due to unaccounted specifics
of the master-slave handshake protocol that sets the Slave_IO_Running
status to true while the semisync master status is set to active a bit later.

The test is refined to expect that.

Fixed that Truncate_versioning_privilege works as any other privilege
during upgrade:

- If the privilege field does not exists, add it to the user and db tables.
  If the user had super_privilege then the user will also get the new
  Truncate_versioning_privilege.

This is done to ensure that if one has GRANT ALL PRIVILEGE before, one
will continue to have it after running mysql_upgrade.

This also fixes a bug where the Truncate_versioning_privilege

dict_tf_is_valid(): Allow no-rollback tables in ROW_FORMAT=REDUNDANT.

MDEV-15091 : Windows, 64bit: reenable and fix warning C4267 (conversion from 'size_t' to 'type', possible loss of data)

Handle string length as size_t, consistently (almost always:))
Change function prototypes to accept size_t, where in the past
ulong or uint were used. change local/member variables to size_t
when appropriate.

This fix excludes rocksdb, spider,spider, sphinx and connect for now.

If setting user variable was used in the specification of a recursive CTE
then Item_func_set_user_var::fix_fields() went into an infinite loop.

                 does not return error

Corrected the code of st_select_lex::find_table_def_in_with_clauses() for
a proper identification of CTE references used in embedded CTEs.

Applying https://github.com/MariaDB/server/pull/594
to bb-10.2-ext

When storing '0001-01-01 10:20:30x', execution went throw the last code
branch in Field_time::store_TIME_with_warning(), around the test
for (ltime->year || ltime->month). This then resulted into wrong results
because:

1. Field_time::store_TIME() does not check YYYYMM against zero.
  It assumes that ltime->days and ltime->hours are already properly set.
  So it mixed days to hours, even when YYYYMM was not zero.

2. Field_time_hires::store_TIME() does not check YYYYMM against zero.
  It assumes that ltime->year, ltime->month, ltime->days and ltime->hours
  are already properly set. So it always mixed days and even months(!) and years(!)
  to hours, using pack_time(). This gave even worse results comparing to #2.

3. Field_timef::store_TIME() did not check the entire YYYYMM for being zero.
  It only checked MM, but did not check YYYY. In case of a zero MM,
  it mixed days to hours, even if YYYY was not zero.
  The wrong code was in TIME_to_longlong_time_packed().

In the new reduction Field_time::store_TIME_with_warning() is responsible
to prepare the YYYYYMMDD part properly in all code branches
(with trailing garbage like 'x' and without trailing garbage).
It was reorganized into a more straightforward style.

Field_time:store_TIME(), Field_time_hires::store_TIME() and
TIME_to_longlong_time_packed() were fixed to do a DBUG_ASSERT
on non-zero ltime->year or ltime->month. The code testing ltime->month
was removed from TIME_to_longlong_time_packed(), as it's now
properly done on the caller level.

Truncation was moved from Field_timef::store_TIME() to
Field_time::store_TIME_with_warning().

So now all thee methods Field_time*::store_TIME() assume a properly
set input value:
- Only zero ltime->year and ltime->month are allowed.
- The value must be already properly truncated according to decimals()
  (this will help to add rounding soon, see MDEV-8894)

A "const" qualifier was added to the argument of Field_time*::store_TIME().

Virtial_tmp_table did not set the "field_index" member for its Fields.
Fixing Virtual_tmp_table::add() to set "field_index" to the Field's ordinal position
inside the table, like a normal TABLE does, for consistency.

Although, this flaw did not seem to cause any bugs, having field_index properly
set is helpful for debugging purposes.

1st. Create_field does not have function vers_sys_field() kind of handy
function, second I think Create_field and Field should not divert much , and
Field does have this function.

2nd. Versioning column does not have NOT_NULL_FLAG, since they can never be
null. So I have added NOT_NULL_FLAG.

3rd. Since I added NOT_NULL_FLAG this created one issue , versioning column
of datatype bigint unsigned were getting NO_DEFAULT_VALUE_FLAG. This makes
test like versioning.insert to fail, Reason being If a column gets this
flag if we insert 'default' value it will generate error(that is why ) test
was failing. So now versioning column wont get NO_DEFAULT_VALUE_FLAG flag.

Problem:-
  create or replace table t1 (pk int auto_increment primary key invisible, i int);
  alter table t1 modify pk int invisible;
 This last alter makes a invisible column which is not null and does not
 have default value.

Analysis:-
 This is caused because our error check for NOT_NULL_FLAG and
 NO_DEFAULT_VALUE_FLAG flag misses this sql_field , but this is not the fault
 of error check :).Actually this field come via mysql_prepare_alter_table
 and it does not have NO_DEFAULT_VALUE_FLAG flag turned on. (If it was create
 table NO_DEFAULT_VALUE_FLAG would have turned on Column_definition::check)
 and this would have generated error.

Solution:-
 I have moved the error check to kind last of mysql_prepare_create_table
 because upto this point we have applied NO_DEFAULT_VALUE_FLAG to required
 column.

Problem:- If we create table field with dynamic default value then that
 field always gets NULL value.

Analyze:- This is because in fill_record we simple continue at Invisible
 column because we though that share->default_values(default value is
 always copied into table->record[0] before insert) will have a default
 value for them(which is true for constant defaults , but not for dynamic
 defaults).

Solution:- We simple set all_fields_have_value to null , and this will
make call to update_default_fields (in the case of dynamic default), And
default expr will be evaluted and value will be set in field.

This will make it easier to how memory allocation is done when debugging
with either DBUG or gdb.

Will especially help when debugging stored procedures

Main change is a name argument as second argument to init_alloc_root()
init_sql_alloc()

Other things:
- Added DBUG_ENTER/EXIT to some Virtual_tmp_table functions

This is to make it a proper class function.

When identifying a table name the following should be taken into account:
a CTE name cannot be qualified with a database name, otherwise the table
name is considered as the name of a non-CTE table.