At least since commit 6a7be48b
InnoDB appears to be invoking buf_flush_note_modification() on pages
that were exclusively latched but not modified in a mini-transaction.

MTR_MEMO_MODIFY, mtr_t::modify(): Define not only in debug code,
but also in release code. We will set the MTR_MEMO_MODIFY flag
on the earliest mtr_t::m_memo entry that we find.

MTR_LOG_NONE: Only use this mode in cases where the previous
mode will be restored before anything is modified in the mini-transaction.

MTR_MEMO_PAGE_X_MODIFY, MTR_MEMO_PAGE_SX_MODIFY: The allowed flag
combinations that include MTR_MEMO_MODIFY.

ReleaseBlocks: Only invoke buf_flush_note_modification()
on those buffer pool blocks on which mtr_t::set_modified()
and mtr_t::modify() were invoked.

In MDEV-21724 or possibly already in MDEV-12353 a bug was introduced to
the handling of temporary tables.

Whether or not redo log will be written, mtr_t::set_modified()
must be invoked to register any changes to a page.

page_cur_insert_rec_low(): Invoke mtr_t::set_modified() also
when skipping the redo log write.

DEB package doesn't need expect and libreadline as dependencies

RPM packages now depends on jemalloc again

On FreeBSD (and possibly elsewhere) the FindPackage(curl)
may have found the curl library in a non-standard directory.

We use the exposed path as a library path to correct linking.

Small postfix to MDEV-23175 to ensure faster option on FreeBSD
and compatibility to Solaris that isn't high resolution.

ftime is left as a backup in case an implementation doesn't
contain any of these clocks.

FreeBSD
    $ ./unittest/mysys/my_rdtsc-t
    1..11
    # ----- Routine ---------------
    # myt.cycles.routine          :             5
    # myt.nanoseconds.routine     :            11
    # myt.microseconds.routine    :            13
    # myt.milliseconds.routine    :            11
    # myt.ticks.routine           :            17
    # ----- Frequency -------------
    # myt.cycles.frequency        :    3610295566
    # myt.nanoseconds.frequency   :    1000000000
    # myt.microseconds.frequency  :       1000000
    # myt.milliseconds.frequency  :           899
    # myt.ticks.frequency         :           136
    # ----- Resolution ------------
    # myt.cycles.resolution       :             1
    # myt.nanoseconds.resolution  :             1
    # myt.microseconds.resolution :             1
    # myt.milliseconds.resolution :             7
    # myt.ticks.resolution        :             1
    # ----- Overhead --------------
    # myt.cycles.overhead         :            26
    # myt.nanoseconds.overhead    :         19140
    # myt.microseconds.overhead   :         19036
    # myt.milliseconds.overhead   :           578
    # myt.ticks.overhead          :         21544
    ok 1 - my_timer_init() did not crash
    ok 2 - The cycle timer is strictly increasing
    ok 3 - The cycle timer is implemented
    ok 4 - The nanosecond timer is increasing
    ok 5 - The nanosecond timer is implemented
    ok 6 - The microsecond timer is increasing
    ok 7 - The microsecond timer is implemented
    ok 8 - The millisecond timer is increasing
    ok 9 - The millisecond timer is implemented
    ok 10 - The tick timer is increasing
    ok 11 - The tick timer is implemented

Previous test failure:

--- /Users/travis/build/grooverdan/mariadb-server/mysql-test/main/mysqld--help-aria.result	2020-04-29 03:44:40.000000000 +0000
+++ /Users/travis/build/grooverdan/mariadb-server/mysql-test/main/mysqld--help-aria.reject	2020-04-29 04:19:13.000000000 +0000
@@ -1,3 +1,4 @@
+[Warning] Setting lower_case_table_names=2 because file system for /Users/travis/build/grooverdan/mariadb-server/mysql-test/var/4/mariadbd.1/data/ is case insensitive
 [ERROR] mariadbd: Can't lock aria aria_log_control for exclusive use, error: #. Will retry for 0 seconds
 [ERROR] Plugin 'Aria' init function returned error.
 [ERROR] Plugin 'Aria' registration as a STORAGE ENGINE failed.
@@ -9,4 +10,5 @@
 #
 # Check with existing directory
 #
+[Warning] Setting lower_case_table_names=2 because file system for /Users/travis/build/grooverdan/mariadb-server/mysql-test/var/tmp/4/help/ is case insensitive
 [Warning] Could not open mysql.plugin table: "Table 'mysql.plugin' doesn't exist". Some options may be missing from the help text

commit b1ab211d (MDEV-15053)
introduced the code to unfix the block earlier in buf_block_t::unfix().
After unfixing the block, InnoDB can withdraw the block from the
buffer pool and deallocate it while doing buffer pool resizing.
So subsequent assert could leads to uninitialized memory access of
block.

buf_block_t::unfix(): Unfix the block after checking the assert.

An overflow was happening with LONGTEXT columns, when the length was converted to the length
in the strxfrm form (mem-comparable keys).
Introduced a function to truncate the length to the max_sort_length before calculating
the length of the strxfrm form.

Changes to be committed:
	modified:   mysql-test/suite/galera_3nodes/t/GCF-354.test
	modified:   mysql-test/suite/galera_3nodes/t/inconsistency_shutdown.test

This happend when using XA transactions. I also added some extra asserts
to ensure that m_transactions are properly cleared.

Other things:
- Removed set_time() from THD::init_for_queries() as dispatch_command()
  is already doing that.
- Removed duplicate init_for_queries() from prepare_new_connection_state().
  The init_for_queries() functions should only be called once per
  connection.

This patch ensures that all identical character sets shares the same
cs->csname.
This allows us to replace strcmp() in my_charset_same() with comparisons
of pointers. This fixes a long standing performance issue that could cause
as strcmp() for every item sent trough the protocol class to the end user.

One consequence of this patch is that we don't allow one to add a character
definition in the Index.xml file that changes the csname of an existing
character set. This is by design as changing character set names of existing
ones is extremely dangerous, especially as some storage engines just records
character set numbers.

As we now have a hash over character set's csname, we can in the future
use that for faster access to a specific character set. This could be done
by changing the hash to non unique and use the hash to find the next
character set with same csname.

The problem was that field_count is not initialized for the Protocol
variable used when printing metadata.

- Better to use 'String *' directly.
- Added String::get_value(LEX_STRING*) for the few cases where we want to
  convert a String to LEX_CSTRING.

Other things:
- Use StringBuffer for some functions to avoid mallocs

- Should speed up replication

- Removed val_str() and print() as these are handled by Item_int()
- Use local StringBuffer for Item_int::print() to avoid mallocs

Starting with MDEV-17441 we would no longer have os_once,
and we would always initialize zip_pad_info_t::mutex and
dict_table_t::autoinc_mutex, even for tables are not in
ROW_FORMAT=COMPRESSED nor include any AUTO_INCREMENT column.

mutex_free() on those unnecessary objects would make shutdown very slow
compared to older versions.

Let us use std::mutex for those two mutexes, to reduce the overhead.
The critical sections protected by these mutexes is very small, and
therefore contention or the need for any instrumentation should
be unlikely.

If there is no current_select and variable is not found among SP variables it can be only an error.

MDEV-23252 Assertion failure 'req_type.is_dblwr_recover() || err == DB_SUCCESS' for page_compressed tables

- This issue is caused by a5584b13
(MDEV-15528). os_file_punch_hole() is added to fil_io() in MDEV-15528.
But it fails to handle failure of os_file_punch_hole(). InnoDB should
handle the DB_IO_NO_PUNCH_HOLE error and silently transform to
DB_SUCCESS. InnoDB should set the punch hole flag correctly when
tablespace is loaded

fil_node_t::read_page0(): Set the punch hole flag when tablespace is loaded

fil_io(): Handle the DB_IO_NO_PUNCH_HOLE error

buf_flush_free_pages(): Checks the punch hole condition earlier using
tablespace punch hole flag

InnoDB should replace FSP_FLAGS_HAS_PAGE_COMPRESSION check with
fil_space_t::is_compressed(). fil_space_t::is_compressed() checks
for both non full crc32 and crc32 format.

InnoDB should replace FSP_FLAGS_HAS_PAGE_COMPRESSION check with
fil_space_t::is_compressed(). fil_space_t::is_compressed() checks
for both non full crc32 and crc32 format.

When high priority replication slave applier encounters lock conflict in innodb,
it will force the conflicting lock holder transaction (victim) to rollback.
This is a must in multi-master sychronous replication model to avoid cluster lock-up.
This high priority victim abort (aka "brute force" (BF) abort), is started
from innodb lock manager while holding the victim's transaction's (trx) mutex.
Depending on the execution state of the victim transaction, it may happen that the
BF abort will call for THD::awake() to wake up the victim transaction for the rollback.
Now, if BF abort requires THD::awake() to be called, then the applier thread executed
locking protocol of: victim trx mutex -> victim THD::LOCK_thd_data

If, at the same time another DBMS super user issues KILL command to abort the same victim,
it will execute locking protocol of: victim THD::LOCK_thd_data  -> victim trx mutex.
These two locking protocol acquire mutexes in opposite order, hence unresolvable mutex locking
deadlock may occur.

The fix in this commit adds THD::wsrep_aborter flag to synchronize who can kill the victim
This flag is set both when BF is called for from innodb and by KILL command.
Either path of victim killing will bail out if victim's wsrep_killed is already
set to avoid mutex conflicts with the other aborter execution. THD::wsrep_aborter
records the aborter THD's ID. This is needed to preserve the right to kill
the victim from different locations for the same aborter thread.
It is also good error logging, to see who is reponsible for the abort.

A new test case was added in galera.galera_bf_kill_debug.test for scenario where
wsrep applier thread and manual KILL command try to kill same idle victim

trx_update_mod_tables_timestamp(): When implementing
innodb_evict_tables_on_commit_debug, do not evict tables
on which transactional locks exist.

This debug variable was broken since its introduction in
commit 947b0b57.

Problem was that the code didn't handle a transaction created in innodb
as part of a failed mysql_lock_tables()

The issue was:
T1, a parallel slave worker thread, is waiting for another worker thread to
commit. While waiting, it has the MDL_BACKUP_COMMIT lock.
T2, working for mariabackup, is doing BACKUP STAGE BLOCK_COMMIT and blocks
all commits.
This causes a deadlock as the thread T1 is waiting for can't commit.

Fixed by moving locking of MDL_BACKUP_COMMIT from ha_commit_trans() to
commit_one_phase_2()

Other things:
- Added a new argument to ha_comit_one_phase() to signal if the
  transaction was a write transaction.
- Ensured that ha_maria::implicit_commit() is always called under
  MDL_BACKUP_COMMIT. This code is not needed in 10.5
- Ensure that MDL_Request values 'type' and 'ticket' are always
  initialized. This makes it easier to check the state of the MDL_Request.
- Moved thd->store_globals() earlier in handle_rpl_parallel_thread() as
  thd->init_for_queries() could use a MDL that could crash if store_globals
  where not called.
- Don't call ha_enable_transactions() in THD::init_for_queries() as this
  is both slow (uses MDL locks) and not needed.

MDEV-22899 Assertion `field->col->is_binary() || field->prefix_len % field->col->mbmaxlen == 0' failed in dict_index_add_to_cache

is_part_of_a_key(): detect is TEXT field is a part of some key

ha_innobase::can_convert_blob(): now correctly detect whether our blob
is a part of some key. Previously the check didn't work in some cases.

Fix stale virtual field value in 4 cases: when virtual field depends
on row_start/row_end in timestamp/trx_id versioned table. row_start
dep is recalculated in vers_update_fields() (SQL and InnoDB
layer). row_end dep is recalculated on history row insert.

MDEV-22061 InnoDB: Assertion of missing row in sec index row_start upon REPLACE on a system-versioned table

make_versioned_helper() appended new update field unconditionally
while it should check if this field already exists in update vector.

Misc renames to conform versioning prefix. vers_update_fields() name
conforms with sql layer TABLE::vers_update_fields().

           when scrubbing is enabled

buf_read_recv_pages(): Ignore the page to read if it is already
present in the freed ranges.

store_freed_or_init_rec(): Store the ranges only if scrubbing
is enabled or page compressed tablespace.

recv_init_crash_recovery_space(): Add the freed range only when
scrubbing or page compressed tablespace.

range_set::contains(): Search the value is present in ranges.

range_set::remove_if_exists(): Remove the value if exist in ranges.

mtr_t::init(): Handles the scenario that mini-transaction may allocate
a page that had just been freed.

recv_sys_t::parse(): Note down the FREE and INIT redo log irrespective
of STORE value.

Removed innodb_tablespaces_scrubbing from test case