This failure was caused by MDEV-25975, which removed the parameter
innodb_disallow_writes.

Added a check for wsrep_sst_disable_writes to the function
ibuf_merge_in_background().

kill_one_thread(): Fix integer sign mismatch in some format strings.
Some of this was introduced
in commit 5c230b21

We will remove the parameter innodb_disallow_writes because it is badly
designed and implemented. The parameter was never allowed at startup.
It was only internally used by Galera snapshot transfer.
If a user executed
SET GLOBAL innodb_disallow_writes=ON;
the server could hang even on subsequent read operations.

During Galera snapshot transfer, we will block writes
to implement an rsync friendly snapshot, as follows:

sst_flush_tables() will acquire a global lock by executing
FLUSH TABLES WITH READ LOCK, which will block any writes
at the high level.

sst_disable_innodb_writes(), invoked via ha_disable_internal_writes(true),
will suspend or disable InnoDB background tasks or threads that could
initiate writes. As part of this, log_make_checkpoint() will be invoked
to ensure that anything in the InnoDB buf_pool.flush_list will be written
to the data files. This has the nice side effect that the Galera joiner
will avoid crash recovery.

The changes to sql/wsrep.cc and to the tests are based on a prototype
that was developed by Jan Lindström.

Reviewed by: Jan Lindström

Some SQL statements that involves subqueries or stored routines could
fail since execution of subqueries or stored routines is not supported
for theses statements. Unfortunately, parsing error could result in
abnormal termination by firing the following assert
  DBUG_ASSERT(m_thd == NULL);
in a destructor of the class sp_head.

The reason of the assert firing is that the method
  sp_head::restore_thd_mem_root()
is not called on semantic action code to clean up resources allocated
during parsing. This happens since the macros YYABORT is called instead of
MYSQL_YYABORT by semantic action code for some grammar rules.

So, to fix the bug YYABORT was just replaced with MYSQL_YYABORT.

after moving fields in optimize_schema_tables_memory_usage()
store default values into their new, moved, locations.

This reverts commit 0812d0de.
But keeps the test case.

followup for 58cd2a8d

The reason for this fix was that when I tried to run mysql_upgrade
at home to update an old 10.5 installation, mysql_upgrade failed
with warnings about mariadb.sys user not existing.

If the server was started with --skip-grants, there would be no warnings
from mysql_upgrade, but in some cases running mysql_upgrade again could
produce new warnings.

The reason for the warnings was that any access of the mysql.user view
will produce a warning if the mariadb.sys user does not exists.

Fixed with the following changes:
- Disable warnings about mariadb.sys user not existing
- Don't overwrite old mariadb.sys entries in tables_priv and global_priv
- Ensure that tables_priv has an entry for mariadb.sys if the user exists.
  This fixes an issue that tables_priv would not be updated if there
  was a failure directly after global_priv was updated.

Server crashed during shutdown with:
"corrupted double-linked list"
when running mysql_upgrade multiple times against the server.

Reason was that db_repostitory could be freed twice.

This commit contains a fix to use modern syntax for selecting
character classes in the tr utility options.

Also one of the tests for SST via rsync (galera_sst_rysnc2) is made
more reliable (to avoid rare failures during automatic testing).

The "const" qualifier was obviously forgotten.

This change will also simpily fixing of MDEV-27744.

Fixing a typo in the fix for MDEV-19804, wrong return value in a bool function:
 < return NULL;
 > return true;

The problem was found because it did not compile on some platforms.

Strangley, it did not have visible problems on other platforms,
which did not fail to compile, although "return NULL" should compile to
"return false" rather than "return true".

tv_usec is a (suseconds_t) so we cast to it. Prevents the AIX(gcc-10) warning:

include/my_time.h: In function 'void my_timeval_trunc(timeval*, uint)':
include/my_time.h:249:65: warning: conversion from 'long int' to 'suseconds_t' {aka 'int'} may change value [-Wconversion]
  249 |   tv->tv_usec-= my_time_fraction_remainder(tv->tv_usec, decimals);
      |

macOS is: conversion from 'long int' to '__darwin_suseconds_t' {aka 'int'} may change value

On Windows suseconds_t isn't defined so we use the existing
long return type of my_time_fraction_remainder.

Reviewed by Marko Mäkelä

Closes: #2079

MDEV-28220: Assert failure in sp_head::~sp_head on parsing a syntax incorrect statement CREATE SEQUENCE ... RESTART inside CREATE PROCEDURE/CREATE FUNCTION

This bug report is about the same issue as MDEV-28129 and MDEV-21173.
The issue is that the macros YYABORT is called instead of MYSQL_YYABORT
on parse error. In result the method LEX::cleanup_lex_after_parse_error
is not called to clean up data structures created on parsing of
the statement.

- Before the patch UPDATE error message for VIR tables was different from TRUNCATE,UPDATE,DELETE
Reviewed by: <Olivier Bertrand>, vicentiu@mariadb.org

We should make sure that wsrep exists before calling wsrep->post_rollback

rpl.rpl_semi_sync_slave_compressed_protocol.test was manually
re-enabled only in 10.3 but left disabled in 10.4+. The fix went
into 10.3+, but the test was left disabled in later versions. This
commit re-enables the test in 10.4+.

This was noticed as part of verifying
MDEV-28186 "crash on startup after crash while regular use"
but is probably not related to the users issue.
Still good to have it fixed

MDEV-27343 Useless warning "InnoDB: Allocated tablespace ID <id> for <tablename>, old maximum was 0" during backup stage

mariabackup does not load dictionary during backup, but it loads
tablespaces, that is why fil_system.max_assigned_id is not set with
dict_check_tablespaces_and_store_max_id(). There is no sense to issue the
warning during backup.

Task 6:
We can find the .frm type of file. If it is sequence then is_sequence
passed to dd_frm_type() will be true. Since there is already a check
to give error message if we trigger is on temporary table or view, an
additional condition is added to check if .frm is sequence
(is_sequence==true) and error message is changed to show
"Trigger's '%-.192s' is view, temporary table or sequence" instead of
"Trigger's '%-.192s' is view or temporary table".

Task 4 and 5:
Already fixed when I started working on bug. Task 4 correctly gives syntax
error ('(' and ')' are not part of create sequence syntax). Task 5 also
gives correct error because s1 is table not sequence. Fails with
ER_NOT_SEQUENCE2

Task 3:
Added an additional condition for SEQUENCE option to check if cache < 0.

Task 2:
changed the error message and made it more reusable.

Task 1:
If table is added to list using option TL_OPTION_SEQUENCE (done when we
have sequence functions) then then we are dealing with sequence instead
of table. So global table list will have sequence set to true. This is
used to check and give correct error message about unknown sequence
instead of table doesn't exist.

MDEV-19631: Assertion `0' failed in st_select_lex_unit::optimize or different plan upon 2nd execution of PS with EXPLAIN

Second execution of a prepared statement for a query containing a constant
subquery with union that can be optimized away, could result in server abnormal
termination for debug build or incorrect result set output for release build.

For example, the following test case crashes a server built with debug on second
run of the statement EXECUTE stmt
  CREATE TABLE t1 (a INT);
  PREPARE stmt FROM 'EXPLAIN SELECT * FROM t1 HAVING 6 IN ( SELECT 6 UNION SELECT 5 )';
  EXECUTE stmt;
  EXECUTE stmt;

The reason for incorrect result set output or abnormal server termination
is careless working with the data member fake_select_lex->options inside
the function mysql_explain_union(). Once the flag SELECT_DESCRIBE is set in
the data member fake_select_lex->option before calling the methods
  SELECT_LEX_UNIT::prepare/SELECT_LEX_UNIT::execute
the original value of the option is no longer restored.
As a consequence, next time the prepared statement is re-executed we have
the fake_select_lex with the flag SELECT_DESCRIBE set in the data member
fake_select_lex->option, that is incorrect. In result, the method
  Item_subselect::assigned()
is not invoked during evaluation of a constant condition (constant subquery
with union) that being performed on OPTIMIZE phase of query handling.

This leads to the fact that records in the temporary table are not deleted
before calling
  table->file->ha_enable_indexes(HA_KEY_SWITCH_ALL)
in the method st_select_lex_unit::optimize().
In result table->file->ha_enable_indexes(HA_KEY_SWITCH_ALL) returns error
and DBUG_ASSERT(0) is fired.

Stack trace to the line where the error generated on re-enabling indexes
for next subselect iteration is below:
st_select_lex_unit::optimize (at sql_union.cc:954)
  handler::ha_enable_indexes (at handler.cc:4338)
    ha_heap::enable_indexes (at ha_heap.cc:519)
      heap_enable_indexes (at hp_clear.c:164)

The code snippet to clarify raising the error is also listed:
int heap_enable_indexes(HP_INFO *info)
{
  int error= 0;
  HP_SHARE *share= info->s;

  if (share->data_length || share->index_length)
    error= HA_ERR_CRASHED; <<== set error the value HA_ERR_CRASHED
                                since share->data_length != 0

To fix this issue the original value of unit->fake_select_lex->options
has to be saved before setting the flag SELECT_DESCRIBE and restored
on return from invocation of SELECT_LEX_UNIT::prepare/SELECT_LEX_UNIT::execute

Fix a possible crash on my_free() due to the use of strdup() versus
my_strdup(), and a memory leak.
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>

As main() invokes parse_page() when -S or -D are set, it can be a case
when parse_page() is invoked when -D filename is not set, that is why
any attempt to write to page dump file must be done only if the file
name is set with -D.

The bug is caused by 2ef7a5a1
(MDEV-13443).

records_are_comparable() requires this condition:

  bitmap_is_subset(table->write_set, table->read_set)

On first iteration vers_update_fields() changes write_set and
read_set. On second iteration the above condition fails.

Added missing read bit for ROW_START. Also reorganized
bitmap_set_bit() so it is called only when needed.

Throw ER_NOT_FORM_FILE if this is wrong FRM data (warning with
ER_VERS_FIELD_WRONG_TYPE is still printed for deeper knowledge of what
was happened).

Keep ER_VERS_FIELD_WRONG_TYPE for creating partitioned table with
trx-versioning. Tested by MDEV-15951 in trx_id.test