signal_hand(): Remove the cmake -DWITH_DBUG_TRACE=ON instrumentation.
It can cause a crash on shutdown when the only other thread is
waiting in wait_for_signal_thread_to_end().

In the JSON functions, the debug injection for stack overflows is
inaccurate and may cause actual stack overflows. Let us simply
inject stack overflow errors without actually relying on the ability
of check_stack_overrun() to do so.

Reviewed by: Rucha Deodhar

Fix a scenario where `mariabackup --prepare` fails with assertion
`!m_modifications || !recv_no_log_write'  in `mtr_t::commit()`. This
happens if the prepare step of the backup encounters a data directory
which happens to store wsrep xid position in TRX SYS page (this is no
longer the case since 10.3.5). And since MDEV-17458,
`trx_rseg_array_init()` handles this case by copying the xid position
to rollback segments, before clearing the xid from TRX SYS page.
However, this step should be avoided when `trx_rseg_array_init()` is
invoked from mariabackup. The relevant code was surrounded by the
condition `srv_operation == SRV_OPERATION_NORMAL`. An additional check
ensures that we are not trying to copy a xid position which has
already zeroed.

- During update operation, InnoDB should avoid the initializing
the FTS_DOC_ID of foreign table if the foreign table is discarded

- Adjust the test case to check whether all tablespaces
are encrypted by comparing it with existing table count.

Few Item_func_json_xxx::fix_length_and_dec() functions fixed.

Correction to ensure compatibility with the updated wsrep-lib library.

Problem:
========
- InnoDB reads the length of the variable length field wrongly
while applying the modification log of instant table.

Solution:
========
rec_init_offsets_comp_ordinary(): For the temporary instant
file record, InnoDB should read the length of the variable length
field from the record itself.

When sending the server default collation ID to the client
in the handshake packet, translate a 2-byte collation ID
to the ID of the default collation for the character set.

When testing MariaDB on Arm64, a stall issue will occur, jira link:
https://jira.mariadb.org/browse/MDEV-28430.

The stall occurs because of an unexpected circular reference in the
LF_PINS->purgatory list which is traversed in lf_pinbox_real_free().

We found that on Arm64, ABA problem in LF_ALLOCATOR->top list was not
solved, and various undefined problems will occur, including circular
reference in LF_PINS->purgatory list.

The following codes are used to solve ABA problem, code copied
from below link.
https://github.com/MariaDB/server/blob/cb4c2713553c5f522d2a4ebf186c6505384c748d/mysys/lf_alloc-pin.c#L501-#L505

     do
     {
503     node= allocator->top;
504     lf_pin(pins, 0, node);
505  } while (node != allocator->top && LF_BACKOFF());

1. ABA problem on Arm64
Combine the below steps to analyze how ABA problem occur on Arm64, the
relevant codes in steps are simplified, code line numbers below are in
MariaDB v10.4.
------------------------------------------------------------------------
Abnormal case.
Initial state: pin = 0, top = A, top list: A->B

T1                              T2
                                step1. write top=B //seq-cst, #L517
                                step2. write A->next= "any"
                                step3. read pin==0 //relaxed, #L295
step1. write pin=A  //seq-cst, #L504
step2. read old value of top==A  //relaxed, #L505
step3. next=A->next="any" //#L517
                                step4. write A->next=B,top=A //#L420-435
step4. CAS(top,A,next) //#L517
step5. write pin=0     //#L521
------------------------------------------------------------------------
Above case is due to T1.step2 reading the old value of top, causing
"T1.step3, T1.step4" and "T2.step4" to occur at the same time, in other
words, they are not mutually exclusive.

It may happen that T2.step4 is sandwiched between T1.step3 and T1.step4,
which cause top to be updated to "any", which may be in-use or invalid
address.

2. Analyze above issue with Dekker's algorithm
Above problem can be mapped to Dekker's algorithm, link is as below
https://en.wikipedia.org/wiki/Dekker%27s_algorithm.
The following extracts the read and write operations on 'top' and 'pin',
and maps them to Dekker's algorithm to analyze the root cause.
------------------------------------------------------------------------
Initial state: top = A, pin = 0
T1                                    T2
store_seq_cst(pin, A) // write pin    store_seq_cst(top, B)  //write top
rt= load_relaxed(top) // read top     rp= load_relaxed(pin)  //read pin

if (rt == A && rp == 0) printf("oops\n"); // will "oops" be printed?
------------------------------------------------------------------------
How T1 and T2 enter their critical section:
(1) T1, write pin, if T1 reads that top has not been updated, T1 enter
its critical section(T1.step3 and T1.step4, try to obtain 'A', #L517),
otherwise just give up (T1 without priority).
(2) T2, write top, if T2 reads that pin has not been updated, T2 enter
critical section(T2.step4, try to add 'A' to top list again, #L420-435),
otherwise wait until pin!=A (T2 with priority).

In the previous code, due to load 'top' and 'pin' with relaxed semantic,
on arm and ppc, there is no guarantee that the above critical sections
are mutually exclusive, in other words, "oops" will be printed.

This bug only happens on arm and ppc, not x86. On current x86
implementation, load is always seq-cst (relaxed and seq-cst load
generates same machine code), as shown in https://godbolt.org/z/sEzMvnjd9

3. Fix method
Add sequential-consistency semantic to read 'top' in #L505(T1.step2),
Add sequential-consistency semantic to read "el->pin[i]" in #L295
and #L320.

4. Issue reproduce
Add "delay" after #L503 in lf_alloc-pin.c, When run unit.lf, can quickly
get segment fault because "top" point to an invalid address. For detail,
see comment area of below link.
https://jira.mariadb.org/browse/MDEV-28430.

5. Futher improvement
To make this code more robust and safe on all platforms, we recommend
replacing volatile with C11 atomics and to fix all data races. This will
also make the code easier to reason.
Signed-off-by: Xiaotong Niu <xiaotong.niu@arm.com>

Thanks to Yury Chaikou for finding this problem (and the fix).
Reviewed-by: Monty <monty@mariadb.org>
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>

my_malloc_size_cb_func() can be called from contexts where it is not safe to
wait for LOCK_thd_kill, for example while holding LOCK_plugin. This could
lead to (probably very unlikely) deadlock of the server.

Fix by skipping the enforcement of --max-session-mem-used in the rare cases
when LOCK_thd_kill cannot be obtained. The limit will instead be enforced on
the following memory allocation. This does not significantly degrade the
behaviour of --max-session-mem-used; that limit is in any case only enforced
"softly", not taking effect until the next point at which the thread does a
check_killed().
Reviewed-by: Monty <monty@mariadb.org>
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>

Aria temporary tables account allocated memory as specific to the current
THD. But this fails for slave threads, where the temporary tables need to be
detached from any specific THD.

Introduce a new flag to mark temporary tables in replication as "global",
and use that inside Aria to not account memory allocations as thread
specific for such tables.

Based on original suggestion by Monty.
Reviewed-by: Monty <monty@mariadb.org>
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>

ha_innobase::check_if_supported_inplace_alter(): Require ALGORITHM=COPY
when creating a FULLTEXT INDEX on a versioned table.

row_merge_buf_add(), row_merge_read_clustered_index(): Remove the parameter
or local variable history_fts that had been added in the attempt to fix
MDEV-25004.

Reviewed by: Thirunarayanan Balathandayuthapani
Tested by: Matthias Leich

After MDEV-31400, plugins are allowed to ask for retries when failing
initialisation. However, such failures also cause plugin system
variables to be deleted (plugin_variables_deinit()) before retrying
and are not re-added during retry.

We fix this by checking that if the plugin has requested a retry the
variables are not deleted. Because plugin_deinitialize() also calls
plugin_variables_deinit(), if the retry fails, the variables will
still be deleted.

Alternatives considered:

- remove the plugin_variables_deinit() from plugin_initialize() error
handling altogether. We decide to take a more conservative approach
here.

- re-add the system variables during retry. It is more complicated
than simply iterating over plugin->system_vars and call
my_hash_insert(). For example we will need to assign values to
the test_load field and extract more code from test_plugin_options(),
if that is possible.

	JOIN::optimize_inner(), Condition pushdown from HAVING into WHERE
	  not shown in optimizer trace.

This patch fixes the issue with passing the DEFAULT or IGNORE values to
positional parameters for some kind of SQL statements to be executed
as prepared statements.

The main idea of the patch is to associate an actual value being passed
by the USING clause with the positional parameter represented by
the Item_param class. Such association must be performed on execution of
UPDATE statement in PS/SP mode. Other corner cases that results in
server crash is on handling CREATE TABLE when positional parameter
placed after the DEFAULT clause or CALL statement and passing either
the value DEFAULT or IGNORE as an actual value for the positional parameter.
This case is fixed by checking whether an error is set in diagnostics
area at the function pack_vcols() on return from the function pack_expression()

MDEV-15703: Crash in EXECUTE IMMEDIATE 'CREATE OR REPLACE TABLE t1 (a INT DEFAULT ?)' USING DEFAULT, UBSAN runtime error: member call on null pointer of type 'struct TABLE_LIST' in Item_param::save_in_field

This is the prerequisite patch to refactor the method
  Item_default_value::fix_fields.
The former implementation of this method was extracted and placed
into the standalone function make_default_field() and the method
Item_default_value::tie_field(). The motivation for this modification
is upcoming changes for core implementation of the task MDEV-15703
since these functions will be used from several places within
the source code.

row_discard_tablespace(): Do not invoke dict_index_t::clear_instant_alter()
because that would corrupt any adaptive hash index entries in the table.

row_import_for_mysql(): Invoke dict_index_t::clear_instant_alter()
after detaching any adaptive hash index entries.

In commit 179424db the file lowercase_table2.result was made executable
for no known reason, most likely just a mistake. Test result files
definitely should not be executable.

All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the
BSD-new license. I am contributing on behalf of my employer Amazon Web
Services, Inc.

This bug was fixed by the patch for bug MDEV-30706.
Only a test case is added in this commit.

test disabled, until fixed

Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>

Ever since commit 5e84ea96
this "else if" branch was unreachable because the preceding
"if" condition covered it.

row_search_mvcc(): Revise an overflow check, disabling it on 64-bit
systems. The maximum number of consecutive record reads in a key range
scan should be limited by the maximum number of records per page
(less than 2^13) and the maximum number of pages per tablespace (2^32)
to less than 2^45. On 32-bit systems we can simplify the overflow check.

Reviewed by: Vladislav Lesin

This was fixed in 10.2 in 2020 but merging the code to 10.3 caused the
bug to come back.

rpl.rpl_seconds_behind_master_spike uses the DEBUG_SYNC mechanism to
count how many format descriptor events (FDEs) have been executed,
to attempt to pause on a specific relay log FDE after executing
transactions. However, depending on when the IO thread is stopped,
it can send an extra FDE before sending the transactions, forcing
the test to pause before executing any transactions, resulting in a
table not existing, that is attempted to be read for COUNT.

This patch fixes this by no longer counting FDEs, but rather by
programmatically waiting until the SQL thread has executed the
transaction and then automatically activating the DEBUG_SYNC point
to trigger at the next relay log FDE.

Add wait_condition to make sure tables are created before next
operations.
Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>

Add wait_condition between debug sync SIGNAL points and other
expected state conditions and refactor actual sync point for
easier to use in test case.
Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>