in trans_xa_start.

        THD.transaction.xid_state.xid.rm_error should be cleaned
        as the thread ends.

Don't call handler->position() if the last call to read a row did
not succeed.

fil_space_t::atomic_write_supported: Always set this flag for
TEMPORARY TABLESPACE and during IMPORT TABLESPACE. The page
writes during these operations are by definition not crash-safe
because they are not written to the redo log.

fil_space_t::use_doublewrite(): Determine if doublewrite should
be used.

buf_dblwr_update(): Add assertions, and let the caller check whether
doublewrite buffering is desired.

buf_flush_write_block_low(): Disable the doublewrite buffer for
the temporary tablespace and for IMPORT TABLESPACE.

fil_space_set_imported(), fil_node_open_file(), fil_space_create():
Initialize or revise the space->atomic_write_supported flag.

buf_page_io_complete(), buf_flush_write_complete(): Add the parameter
dblwr, to indicate whether doublewrite was used for writes.

buf_dblwr_sync_datafiles(): Remove an unnecessary flush of
persistent tablespaces when flushing temporary tablespaces.
(Move the call to buf_dblwr_flush_buffered_writes().)

buf_flush_init_for_writing(): Remove the parameter skip_checksum.

fsp_init_file_page_low(): Always initialize the page.

There were some differences on MariaDB compared with MySQL.
Fix these differences.

MDEV-15420 Wrong result for CAST from TIME or DATETIME with zero integer part and non-zero microseconds to DECIMAL(X,Y)

The loop in ull2dec() does not iterate if "from" is zero,
so to->intg got erroneously set to 0 instead of 1.
Because if this, my_decimal2seconds() wrote the fractional
part into a wrong buf[x].

Catching the special case with zero "from" and properly initialize "to"
using decimal_make_zero().

MDEV-14814: encryption.innodb_encryption-page-compression failed in buildbot with timeout on wait condition

Fix wrong wait condition.

fix the compilation error.
no support for plugins yet.

rocksdb and spider

despite the name, it logs both stdout and stderr

tokudb apparently requires perfschema now

Analysis:- The problem  is the change in the implementation of wait_for_listen
in wsrep_sst_xtrabackup-v2.sh. The new script uses lsof which will always
exit with an error code if it can't find all the items, and because the
script has the -e option set in the hashbang line (#!/bin/bash -ue), the
script will abort right after running lsof if lsof can't find even a single
item among all the items listed in its arguments. This will happen even if
socat is running and listening, because it can't find nc. The loop in
wait_for_listen will therefore always quit after one iteration without
writing the "ready" line to signal the parent.

Solution:- We will or the lsof with true.

Patch Credit :Daniel Black and David Wang

Part #2: some transactions have m_rocksdb_tx==NULL (and most functions of
Rdb_transction_impl handle this case. Do like they do)

Make MyRocks' non-XA commit path to first do the commit without syncing
and then sync.

a) We do not need this on Windows, and it is not clear what it does,inside
service.

b) It hinders debugging.
mysql-test-run.pl --debugger=vsjitdebugger more often than , would stop here
throwing "invalid handle" exception.

* galera_gtid_slave
* galera_unicode_identifiers

            the non-recursive CTE via prepared statement

The problem appears as the column names of the CTE were allocated on the
wrong MEMROOT and after the preparation of the statement they disappear.

To fix it in the procedure With_element::rename_columns_of_derived_unit
the CTE column names are now allocated in the permanent MEMROOT for the
prepared statements and stored procedures.

This reverts commit 0ea45725,
since it breaks clang

fsp_fill_free_list(): Correctly determine whether the temporary
tablespace file should be extended in order to respond to a
page allocation request. The inverted condition was noticed
by Thiru when he analyzed MDEV-13013.

Added more files affected by GCC ICE:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67143

Added missing include.

srv_conc_t::n_active: Correct the comment, and remove an
assertion that trivially holds now that the type is unsigned.

MDEV-14814: encryption.innodb_encryption-page-compression failed in buildbot with timeout on wait condition

Test changes only.