Fix function `remove_fragment()` in wsrep_schema so that no error is
raised if the fragment to be removed is not found in the
wsrep_streaming_log table. This is necessary to handle the case where
streaming transaction in idle state is BF aborted. This may result in
the case where the rollbacker thread successfully removes the
transaction's fragments, followed by the applier's attempt to remove
the same fragments. Causing the node to leave the cluster after
reporting a "Failed to apply write set" error.
Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>

This fixes up 83a87da4

This had become unused in commit 2e814d47
or mysql/mysql-server@eca5b0fc17a5bd6d4833d35a0d08c8549dd3b5ec.
This cleanup affects mtr_buf_t::used().

MTR buildbot output suggest that buildbot can lose some stdout information
by overwriting it with stderr, which is captured separately

This is bad, since stdout contains information about failing test.
So, this is an attempt to minimize the damage by excluding most frequent
stderr messages - those about restart.

An attempt to fix lost output sometimes seen on buildbot.

MDEV-31154 Fatal InnoDB error or assertion `!is_v' failure upon multi-update with indexed virtual column
MDEV-33558 Fatal error InnoDB: Clustered record field for column x not found

This is issue is about row ID filtering used with index on virtual
column(s). We hit debug assert and crash while building the record
template in Innodb. The primary reason is that we try to force the code
path to use the ICP path. With ICP, we don't support index with virtual
column and we validate it while index condition is pushed.

Simplify the code for building template to handle both ICP and Row ID
filtering by skipping virtual columns.

Problem:
======
- InnoDB fail to do instant operation while adding the variable
length column. Problem is that InnoDB wrongly assumes that
variable character length can never part of externally stored
page.

Solution:
========
instant_alter_column_possible(): Variable length
character field can be stored as externally stored page.

There were several races in the main.kill_processlist-6619 testcase:

 - Lingering connections from a previous test case could be visible in SHOW
   PROCESSLIST and cause .result diff.
 - A sync point "dispatch_command_end" was ineffective, as it was consumed at
   the end of the SET DEBUG command itself.
 - The signal from sync point "before_execute_sql_command" could override an
   earlier signal, causing DEBUG_SYNC timeout and test failure.
 - The final SHOW PROCESSLIST could occasionally see a connection in state
   "Busy" instead of the expected "Sleep".
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>

The problem was that SHOW PROCESSLIST was done before the command of
the default connection was cleared.

Reviewer: Sergei Golubchik <serg@mariadb.org>

MDEV-33218: Assertion `active_arena->is_stmt_prepare_or_first_stmt_execute() || active_arena->state == Query_arena::STMT_SP_QUERY_ARGUMENTS' failed in st_select_lex::fix_prepare_information

In case there is a view that queried from a stored routine or
a prepared statement and this temporary table is dropped between
executions of SP/PS, then it leads to hitting an assertion
at the SELECT_LEX::fix_prepare_information. The fired assertion
 was added by the commit 85f2e4f8
(MDEV-32466: Potential memory leak on executing of create view statement).
Firing of this assertion means memory leaking on execution of SP/PS.
Moreover, if the added assert be commented out, different result sets
can be produced by the statement SELECT * FROM the hidden table.

Both hitting the assertion and different result sets have the same root
cause. This cause is usage of temporary table's metadata after the table
itself has been dropped. To fix the issue, reload the cache of stored
routines. To do it  cache of stored routines is reset at the end of
execution of the function dispatch_command(). Next time any stored routine
be called it will be loaded from the table mysql.proc. This happens inside
the method Sp_handler::sp_cache_routine where loading of a stored routine
is performed in case it missed in cache. Loading is performed unconditionally
while previously it was controlled by the parameter lookup_only. By that
reason the signature of the method Sroutine_hash_entry::sp_cache_routine
was changed by removing unused parameter lookup_only.

Clearing of sp caches affects the test main.lock_sync since it forces
opening and locking the table mysql.proc but the test assumes that each
statement locks its tables once during its execution. To keep this invariant
the debug sync points with names "before_lock_tables_takes_lock" and
"after_lock_tables_takes_lock" are not activated on handling the table
mysql.proc

When rolling back and retrying a transaction in parallel replication, don't
release the domain ownership (for --gtid-ignore-duplicates) as part of the
rollback. Otherwise another master connection could grab the ownership and
double-apply the transaction in parallel with the retry.
Reviewed-by: Brandon Nesterenko <brandon.nesterenko@mariadb.com>
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>

Added commands to the help

Follow-up to fix comiler warings caused by present of
the clause override in declaration of the method Item_param::cleanup

UPDATE statement that is run in PS mode and uses positional parameter
handles columns declared with the clause DEFAULT NULL incorrectly in
case the clause DEFAULT is passed as actual value for the positional
parameter of the prepared statement. Similar issue happens in case
an expression specified in the DEFAULT clause of table's column definition.

The reason for incorrect processing of columns declared as DEFAULT NULL
is that setting of null flag for a field being updated was missed
in implementation of the method Item_param::assign_default().
The reason for incorrect handling of an expression in DEFAULT clause is
also missed saving of a field inside implementation of the method
Item_param::assign_default().

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.