1. moved fix_vcol_exprs() call to open_table()

mysql_alter_table() doesn't do lock_tables() so it cannot win from
fix_vcol_exprs() from there. Tests affected: main.default_session

2. Vanilla cleanups and comments.

UNION ALL queries are a subject of optimization introduced in MDEV-334
when creation of a temporary table is skipped.
While there is a check for this optimization in Explain_union::print_explain()
there was no such in Explain_union::print_explain_json(). This resulted in
printing irrelevant data like:
  "union_result": {
    "table_name": "<union2,3>",
    "access_type": "ALL",
    "r_loops": 0,
    "r_rows": null
in case when creation of the temporary table was actually optimized out.
This commits adds a check whether the temporary table was actually created
during the UNION ALL processing and eliminates printing of the irrelevant data.

An additional patch for MDEV-27690 Crash on `CHARACTER SET csname COLLATE DEFAULT` in column definition

Applying the fix to sql_yacc_ora.yy. Adding a test for sql_mode=ORACLE.

on_table_fill_finished() should always be done at the end of open()
even if result is not Select_materialize but (for example)
Select_fetch_into_spvars.

This is conceptually a backport of
commit 6f4740fd
(re-recording the .rdiff files).

This commit fixes problems with parsing ipv6 addresses given via
the wsrep_sst_receive_address and wsrep_node_address options.

Also, this commit removes extra lines in the configuration files
in the mtr test suites for Galera related to these parameters.

fix bad merge

MDEV-24317 Data race in LOGGER::init_error_log at sql/log.cc:1443 and in LOGGER::error_log_print at sql/log.cc:1181

don't initialize error_log_handler_list in set_handlers()
* error_log_handler_list is initialized to LOG_FILE early, in init_base()
* set_handlers always reinitializes it to LOG_FILE, so it's pointless
* after init_base() concurrent threads start using sql_log_warning,
  so following set_handlers() shouldn't modify error_log_handler_list
  without some protection

I change from `exit;` to `exit(1);` on a function `usage()`.
When we try to run mtr with a wrong option, a function `usage()` is called with the wrong option as its argument. In this case, because the function call `exit` in a first if statement, we get exit status 0.

This is a temporary fix for 10.2.
This problem was permanently fixed in 10.9 under terms of MDEV-27743.

This patch should propagate up to 10.8 then null-merged to 10.9.

The issue was that the value of MARIA_FOUND_WRONG_KEY was a value
that could be returned by ha_key_cmp.

This was already fixed in MyISAM, now using the same fix in Aria:
Setting the value to INT_MAX32, which should be impossible in any
normal cases.

I also fixed so that if there is a wrong key, we now get a proper error
message and not an assert.

Creating a temporary table with Spider is non-sense because a Spider
table cannot hold any physical data and it requires an additional
effort to manage even if it is configured correctly.

Set HTON_TEMPORARY_NOT_SUPPORTED to spider_hton->flags.  

Reviewed-by: nayuta.yanagisawa@hey.com
Co-authored-by: d8sk4ueun@gmail.com

This crash happens on a combination of multiple conditions:

- There is a thead#1 running an "ANALYZE FORMAT=JSON" query for a
  "SELECT .. FROM INFORMATION_SCHEMA.COLUMNS WHERE .. "
- The WHERE clause contains a stored function call, say f1().
- The WHERE clause is built in the way so that the function f1()
  is never actually called, e.g.
    WHERE .. AND (TRUE OR f1()=expr)
- The database contains multiple VIEWs that have the function f1() call,
  e.g. in their <select list>
- The WHERE clause is built in the way so that these VIEWs match
  the condition.
- There is a parallel thread#2 running. It creates or drops or recreates
  some other stored routine, say f2(), which is not used in the ANALYZE query.
  It effectively invalidates the stored routine cache for thread#1
  without locking.
  Note, it is important that f2() is NOT used by ANALYZE query.
  Otherwise, thread#2 would be locked until the ANALYZE query
  finishes.

When all of the above conditions are met, the following happens:

1. thread#1 starts the ANALYZE query. It notices a call for the stored function
   f1() in the WHERE condition. The function f1() gets parsed and cached
   to the SP cache. Its address also gets assigned to Item_func_sp::m_sp.

2. thread#1 starts iterating through all tables that
   match the WHERE condition to find the information about their columns.

3. thread#1 processes columns of the VIEW v1.
   It notices a call for f1() in the VIEW v1 definition.
   But f1() is already cached in the step#1 and it is up to date.
   So nothing happens with the SP cache.

4. thread#2 re-creates f2() in a non-locking mode.
   It effectively invalidates the SP cache in thread#1.

5. thread#1 processes columns of the VIEW v2.
   It notices a call for f1() in the VIEW v2 definition.
   It also notices that the cached version of f1() is not up to date.
   It frees the old definition of f1(), parses it again, and puts a
   new version of f1() to the SP cache.

6. thread#1 finishes processing rows and generates the JSON output.
   When printing the "attached_condition" value, it calls
   Item_func_sp::print() for f1(). But this Item_func_sp links
   to the old (freed) version of f1().

The above scenario demonstrates that Item_func_sp::m_sp can point to an
alredy freed instance when Item_func_sp::func_name() is called,
so accessing to Item_sp::m_sp->m_handler is not safe.

This patch rewrites the code to use Item_func_sp::m_handler instead,
which is always reliable.

Note, this patch is only a cleanup for MDEV-28166 to quickly fix the regression.
It fixes MDEV-28267. But it does not fix the core problem:
The code behind I_S does not take into account that the SP
cache can be updated while evaluating rows of the COLUMNS table.
This is a corner case and it never happens with any other tables.
I_S.COLUMNS is very special.

Another example of the core problem is reported in MDEV-25243.
The code accesses to Item_sp::m_sp->m_chistics of an
already freed m_sp, again. It will be addressed separately.

MDEV-22282 When using mysqldump to backup a view that contains derived tables, the database name is prepended to each table in the view

derived tables have db = "", table_name = "*", those aren't real names
to be compared with.

The partitioning engine does not support the table-level DATA/INDEX
DIRECTORY specification.

If one create a non-partitioned table with the DATA/INDEX DIRECTORY
option and then performs ALTER TABLE ... PARTITION BY on it, the
DATA/INDEX DIRECTORY specification of the old schema is ignored.

The behavior might be a bit surprising for users because the value
of a usual table option applies to all the partitions. Thus, we raise
a warning on such ALTER TABLE ... PARTITION BY.

Adding an MTR test only.

This problem was earlier fixed by the patch for:
  MDEV-28078 Garbage on multiple equal ENUMs with tricky character sets

The original query "SELECT IF(COUNT(a.`id`)>=0,'Y','N') FROM t" is
transformed to "SELECT COUNT(a.`id`), IF(ref >= 0, 'Y', 'N') FROM t",
where ref is Item_ref to "COUNT(a.`id`)", by split_sum_func().

Spider walks the item list twice, invoking spider_db_print_item_type().
The first invocation is in spider_create_group_by_handler() with
str == NULL. The second one is in spider_group_by_handler::init_scan()
with str != NULL.

spider_db_print_item_type() prints nothing at the first invocation,
and it prints item at the second invocation. However, at the second
invocation, the above mentioned ref to "COUNT(a.`id`)" points to
a field in a temporary table where the result will be stored. Thus,
to look behind the item_ref, Spider need to generate the query earlier.

A possible fix would be to generate a query to send in
spider_create_group_by_handler(). However, the fix requires a
considerable amount of changes of the Spider's GROUP BY handler.
I'd like to avoid that.

So, I fix the problem by not to use the GROUP BY handler when a
query contains Item_ref whose table_name, name, and alias_name_used
are not set.

Currenly SST script for mariabackup stops on any failure while archiving
logs, e.g. when unable to create directory, insufficient permissions, gzip
failure, etc. However, in case of such problems, the script should issue
a warning and continue without archiving, but not exit with a fatal error.

This commit adds this fix to the SST script for mariabackup.

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().

The cause of the bug is overflow of uint16 KEY_PART_INFO::length and/or
uint16 KEY_PART_INFO::store_length. The solution is to increase the size
of those variables to the 'uint' type (which is 32-bit long)

If JOIN::create_postjoin_aggr_table encounters errors during execution
then free_tmp_table() is then called twice for JOIN_TAB::aggr.
The solution is to initialize JOIN_TAB::aggr only on successful completion
of JOIN::create_postjoin_aggr_table

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

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

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.

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

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.

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

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).