In thread caching code, clear THD's warnings before reuse.

There is not current SELECT during assigning SP parameters, do not use it if current_select is empty.

fts_sync(): If the dict_table_t::to_be_dropped flag is set,
do not "goto begin_sync".

Also, clean up the way how dict_index_t::index_fts_syncing
is cleared.

It looks like this regression was introduced by merging
Oracle Bug #24938374 MYSQL CRASHED AFTER LONG WAIT ON DICT OPERATION LOCK
WHILE SYNCING FTS INDEX
https://github.com/mysql/mysql-server/commit/068f8261d4c1e134965383ff974ddf30c0758f51
from MySQL 5.6.38 into MariaDB 10.0.33, 10.1.29, 10.2.10.
The same hang is present in MySQL 5.7.20.

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.

MDEV-14648 Restore fix for MySQL BUG#39053 - UNINSTALL PLUGIN does not allow the storage engine to cleanup open connections

ha_close_connection(): Do invoke the method also for plugins
for which UNINSTALL PLUGIN was deferred due to open connections.

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

InnoDB in Debian uses utf8mb4 as default character set since
version 10.0.20-2. This leads to major pain due to keys longer
than 767 bytes.

MariaDB 10.2 (and MySQL 5.7) introduced the setting
innodb_default_row_format that is DYNAMIC by default. These
versions also changed the default values of the parameters
innodb_large_prefix=ON and innodb_file_format=Barracuda.
This would allow longer column index prefixes to be created.
The original purpose of these parameters was to allow InnoDB
to be downgraded to MySQL 5.1, which is long out of support.

Every InnoDB version since MySQL 5.5 does support operation
with the relaxed limits.

We backport the parameter innodb_default_row_format to
MariaDB 10.1, but we will keep its default value at COMPACT.
This allows MariaDB 10.1 to be configured so that CREATE TABLE
is less likely to encounter a problem with the limitation:

	loose_innodb_large_prefix=ON
	loose_innodb_default_row_format=DYNAMIC

(Note that the setting innodb_large_prefix was deprecated in
MariaDB 10.2 and removed in MariaDB 10.3.)

The only observable difference in the behaviour with the default
settings should be that ROW_FORMAT=DYNAMIC tables can be created
both in the system tablespace and in .ibd files, no matter what
innodb_file_format has been assigned to. Unlike MariaDB 10.2,
we are not changing the default value of innodb_file_format,
so ROW_FORMAT=COMPRESSED tables cannot be created without
changing the parameter.

fix 50359719
don't rely on any specific engine checking order

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.

prevents buffering in cases like

  ./mtr | tee log

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.