Item_cache::is_null() erroneously returned null_value in a
non-cached state. Now Item_cache::is_null() uses has_value(),
which caches the value if not cached yet, similar to what other value methods do
(e.g. val_int, val_real, etc).

Using IP address in donor's socat with TLS/SSL and certificate
which doesn't contain IP address in CN or SubjectAltName causes
transfer to fail with message:

socat[5799] E certificate is valid but its commonName does not
match hostname.

This patch tries to reverse resolve IP address to hostname and
use it for transfer. If reverse resolution fails, IP address is
still used as fall-back, so proper A/AAAA and PTR records are
important, but not mandatory.

Certain certificates cannot contain IP addresses, e.g. FreeIPA's
Dogtag doesn't allow it, so in my case I would need to use self-
signed certificates instead, use verify=0 with socat or don't use
TLS/SSL at all. Issue is mentioned in MDEV-9403.

Since wsrep_sync_wait & wsrep_causal_reads variables are related,
they are always kept in sync whenever one of them changes.
Same is tried on server start, where wsrep_sync_wait get updated
based on wsrep_causal_reads' value. But, since wsrep_causal_reads
is OFF by default, wsrep_sync_wait's value gets modified and loses
its WSREP_SYNC_WAIT_BEFORE_READ bit.

Fixed by syncing wsrep_sync_wait & wsrep_causal_reads values
individually on server start in mysqld_get_one_option() based
on command line arguments used.

Added a new --wsrep-new-cluster option to enable mysqld_multi
script to start mysqld with the same option.

[Patch contributed by Hartmut]

Append mysqld_safe's wsrep-on option to the list of options
used to start mysqld.
[Patch contributed by Hartmut]

In CTAS, handlers get registered under statement transaction
(st_transactions::stmt), while ha_fake_trx_id(), used by CTAS,
looked under standard transaction (st_transactions::all) for
registered handlers, and thus it failed to grab a fake transaction
ID. As a result, with no valid transaction ID, wsrep commit failed
with an error.

ha_fake_trx_id() now looks for handlers registered under 'stmt'
in case 'all' is empty. Also modified the logic to print warning
only once if none of the registered handlers have fake_trx_id.

On wsrep_cluster_address update, node restarts the replication
and attempts to connect to the new address. In this process it
makes a call to wsrep provider's connect API, which could lead
to segfault if wsrep provider is not loaded (wsrep_on=OFF).

Fixed by making sure that it proceeds only if a provider is
loaded.

Update sys_vars.sysvars_wsrep test.

Galera recovery process works in two phases. In the first
phase, mysqld is started as non-daemon with --wsrep-recover
to recover and fetch the last logged global transaction ID.
This ID is then used in second phase as the start position
(--wsrep-start-position=XX) to start mysqld as daemon.

As this process was implemented in mysqld_safe script, the
recovery did not work when server was started using systemd.

Fixed by introducing a shell script (wsrep_recovery.sh) that
mimics the first phase of the recovery process.

--defaults-xxx options must be placed before all other
options in the command line. Also moved MYSQLD_OPTS at
the end so that its options take precedence.

errno must be reset before strtol()/strtoll() functions
are invoked.

Fixed by using hostname (glob_hostname) as default value for
wsrep_node_name system variable.
Added a test case.

        Servers sets default DEFINER to empty if run with the
        --scip-grant-tables option.
        So specify the DEFINER explicitly

    Compiler on Sparc is strict about the 'const' modifiers
    in function declarations and definitions. Meaning
    they should be exactly same.

MDEV-10277 Redundant NOTE when inserting '0.00001 ' into a DECIMAL(2,1) column

MDEV-10214: Fix segfault when using groups in PAM user mapping plugin

MDEV-8686 A user defined collation utf8_confusables doesn't work
25e68c5e

The collation customization code for the UCA (Unicode Collation Alrorithm)
based collations now allows to reset to and shift of characters with
implicit weights. Previously reset/shift worked only for the characters
with explicit DUCET weights. An attempt to use reset/shift with
character with implicit weights made the server crash.

Make tree_or set correct SEL_TREE::keys_map for the result.

Fixed mysql-test-run failures for roles.acl_statistics

The check inserts a DWARF directive to tell stack unwinding that the
bottom of the (co-routine) stack has been reached. Without this, stack
traces may attempt to continue past the bottom of the stack.

The GCC version check was incorrect, and failed to trigger for GCC
version 5.[0123].

On Windows with low precision  (10-16 ms) timer used for timing queries,
the statement "set @@long_query_time=0.01" can log itself a slow if it
spawn more single timer tick.

The fix is to filter this query out  from "SELECT FROM mysql.slow_log"
results

Make the range optimizer not call records_in_range() when it would
not give any benefit.

Part #2: make tree_or(tree1, tree2) to reuse tree1 for the result object
for simple cases. These include key IN (c1, ... cN).

The reuse was happening in old MySQL versions, but we stopped doing it
in the "fair choice between range and index_merge" patch.

MDEV-10154 - Remove some unnecessary parentheses

Post-fix #2:
- Update test results
- Make the optimization conditional under @@optimizer_switch flag.
- The optimization is now disabled by default, so .result files
  are changed back to be what they were before the MDEV-8989 patch.

Add big_test and not_debug requirements to avoid timeouts.

Fix spelling: shhould -> should

A partial backport of 67f21fb3a077dedfd14b9ca720e926c55e682f93,
Bug#22283790: RANGE OPTIMIZER UTILIZES TOO MUCH MEMORY WITH MANY OR CONDITIONS

The backported part changes SEL_TREE::keys from being an array of
MAX_KEY elements (64*8=512 bytes) to a Mem_root_array<SEL_ARG*> (32 bytes +
alloc'ed array of as many elements as we need).

The patch doesn't fix the "not limiting memory" part, but the memory usage
is much lower with it.