MDEV-17711 Assertion `arena_for_set_stmt== 0' failed in LEX::set_arena_for_set_stmt upon SET STATEMENT

restore SET STATEMENT variables between statements in a multi-statement

compaitibility with:
* chacha - mobile devices
* secure negotiation - openssl 3

The problem is in manager/worker communication when worker sends
WARNINGS and then TESTRESULT. If manager yet didn't read WARNINGS
response both responses get into the same buffer, can_read() will
indicate we have data only once and we must read all the data from the
socket at once. Otherwise TESTRESULT response is lost and manager
waits it forever.

The fix now instead of single line reads the socket in a loop. But if
there is only one response in the buffer the second read will be
blocked waiting until new data arrives. That can be overcame by
blocking(0) which sets the handle into non-blocking mode. If there is
no data second read just returns undef.

The problem is non-blocking mode is not supported by all perl flavors
on Windows. Strawberry and ActiveState do not support it. Cygwin and
MSYS2 do support. There is some ioctl() hack that was known to "work"
but it doesn't do what is expected (it does not return data when there
is data). So for Windows if it is not Cygwin we disable the fix.

MSYS2 is basically Cygwin, except it has more easy installation (but
with tools which are not used) and it has some more control of path
conversion via MSYS2_ARG_CONV_EXCL and MSYS2_ENV_CONV_EXCL. So it
should be more Windows-friendly than Cygwin.

Installation

Similar to Cygwin, except installing patch requires additional command
run from shell:

    pacman -S patch

MSYS2 still doesn't work as it returns wierd "Bad address" when
exec-ing forked process from create_process(). Same exec from
standalone perl -e runs just fine... :(

Cygwin is more Unix-oriented. It does not treat \n as \r\n in regexps
(fixed by \R), it supplies Unix-style paths (fixed by
mixed_path()). It does some cleanup on paths when running exe, so it
will be different in exe output (like with $exe_mysqld, comparing
basename() is enough).

Cygwin installation

1. Just install latest perl version (only base package) and
   patchutils from cygwin-setup;
2. Don't forget to add c:\cygwin64\bin into system path
   before any other perl flavors;
3. There is path-style conflict (see below), you must replace
   c:\cygwin64\bin\sh.exe with the wrapper. Run MTR with
   --cygwin-subshell-fix=do for that. Make sure you are running Cygwin
   perl for the option to work.
4. Restart buildbot via net stop buildbot; net start buildbot

Path-style conflict of Cygwin-ish Perl

Some exe paths are passed to mysqltest which are executed by a native
call. This requires native-style paths (\-style). These exe paths also
executed by Perl itself. Either by MTR itself which is not so
critical, but also by tests' --perl blocks which is impossible to
change. And if Perl detects shell-expansion or uses pipe command it
passess this exe path to /bin/sh which is Cygwin-compiled bash that
cannot work with \-style (or at least in -c processing). Thus we require
\-style on some parts of MTR execution and /-style on another parts.

The examples of tests which cover these different parts are:

    main.mysqlbinlog_row_compressed \
    main.sp_trans_log

That could be great to force Perl to use something different from
/bin/sh, but unfortunately /bin/sh is compiled-in into binary. So the
only solution left is to overwrite /bin/sh with some wrapper script
which passes the command to cmd.exe instead of bash.

See "Path-style conflict" in "MDEV-30836 MTR Cygwin fix" for explanation.

To install subshell fix use --cygwin-subshell-fix=do
To uninstall use --cygwin-subshell-fix=remove

This works only from Cygwin environment. As long as perl on PATH is
from Cygwin you are on Cygwin environment. Check it with

     perl --version

     This is perl 5, version 36, subversion 1 (v5.36.1) built for
     x86_64-cygwin-threads-multi

run_test_server() is actually manager main loop. We move out this
function into Manager package and split into run() and
parse_protocol(). The latter is needed for the fix. Moving into
separate package helps to make some common variables which was local
to run_test_server().

Functions from the main package is now prefixed with main:: (should be
reorganized somehow later or auto-imported).

1. Better logging and error reporting;
2. Worker process title;
3. Some comments

Worker process title example:

 446209 pts/2    R+     0:00 mysql-test-run.pl worker[01] :42146 -> :35027 versioning.view
 446210 pts/2    S+     0:00 mysql-test-run.pl worker[02] :42150 -> :35027 versioning.view
 446211 pts/2    S+     0:00 mysql-test-run.pl worker[03] :42154 -> :35027 versioning.foreign
 446212 pts/2    S+     0:00 mysql-test-run.pl worker[04] :42160 -> :35027 versioning.autoinc

Manager-worker localhost socket connection is represented by a pair :source -> :destination ports.

-vv Now adds --verbose to mysqltest as well, see var/mysqltest.log for the output.

Create test for for case insensitive gives a basic warning on creating
a test file and the next thing a user might see is an abort.

ProtectHome and other systemd setting protect system services from
accessing user data. Unfortunately some of our users do put things
on /home due space or other reasons.

Rather than enumberate the systemd options in a very clunkly fragile
way we put an error associated with the "Can't create test file" and
hope the user can work it out from there.

%M tip thanks Sergei.

Fixed memory leak taken place on executing a prepared statement or
a stored routine that querying a view and this view constructed
on an information schema table. For example,

Lets consider the following definition of the view 'v1'
CREATE VIEW v1 AS SELECT table_name FROM information_schema.views
ORDER BY table_name;

Querying this view in PS mode result in hit of assert.
PREPARE stmt FROM "SELECT * FROM v1";
EXECUTE stmt;
EXECUTE stmt; (*)

Running the statement marked with (*) leads to a crash in case
server build with mode to control allocation of a memory from SP/PS
memory root on the second and following executions of PS/SP.

The reason of leaking the memory is that a memory allocated on
processing of FRM file for the view requested from a PS/PS memory
root meaning that this memory be released only when a stored routine
be evicted from SP-cache or a prepared statement be deallocated
that typically happens on termination of a user session.

To fix the issue switch to a memory root specially created for
allocation of short-lived objects that requested on parsing FRM.

In case a table accessed by a PS/SP is dropped after the first execution of
PS/SP and a view created with the same name as a table just dropped then
the second execution of PS/SP leads to allocation of a memory on SP/PS
memory root already marked as read only on first execution.

For example, the following test case:
CREATE TABLE t1 (a INT);
PREPARE stmt FROM "INSERT INTO t1 VALUES (1)";
EXECUTE stmt;
DROP TABLE t1;
CREATE VIEW t1 S SELECT 1;
--error ER_NON_INSERTABLE_TABLE
EXECUTE stmt; # (*)
DROP VIEW t1;

will hit assert on running the statement 'EXECUTE stmt' marked with (*)
when allocation of a memory be performed on parsing the view.

Memory allocation is requested inside the function mysql_make_view
when a view definition being parsed. In order to avoid an assertion
failure, call of the function mysql_make_view() must be moved after
invocation of the function check_and_update_table_version().
It will result in re-preparing the whole PS statement or current
SP instruction that will free currently allocated items and reset
read_only flag for the memory root.

Moved call of the function check_and_update_table_version() just
before the place where the function extend_table_list() is invoked
in order to avoid allocation of memory on a PS/SP memory root
marked as read only. It happens by the reason that the function
extend_table_list() invokes sp_add_used_routine() to add a trigger
created for the table in time frame between execution the statement
EXECUTE `stmt_id` .

For example, the following test case
create table t1 (a int);

prepare stmt from "insert into t1 (a) value (1)";
execute stmt;

create trigger t1_bi before insert on t1 for each row
  set @message= new.a;

execute stmt; # (*)

adds the trigger t1_bi to a list of used routines that involves
allocation of a memory on PS memory root that has been already marked
as read only on first run of the statement 'execute stmt'.
In result, when the statement marked with (*) is executed it results in
assert hit.

To fix the issue call the function check_and_update_table_version()
before invocation of extend_table_list() to force re-compilation of
PS/SP that resets read-only flag of its memory root.

It is done now before call of select_lex->setup_ref_array()
in order to avoid allocation of SP/PS's memory on its second invocation.

This patch adds support for controlling of memory allocation
done by SP/PS that could happen on second and following executions.
As soon as SP or PS has been executed the first time its memory root
is marked as read only since no further memory allocation should
be performed on it. In case such allocation takes place it leads to
the assert hit for invariant that force no new memory allocations
takes place as soon as the SP/PS has been marked as read only.

The feature for control of memory allocation made on behalf SP/PS
is turned on when both debug build is on and the cmake option
-DWITH_PROTECT_STATEMENT_MEMROOT is set.

The reason for introduction of the new cmake option
  -DWITH_PROTECT_STATEMENT_MEMROOT
to control memory allocation of second and following executions of
SP/PS is that for the current server implementation there are too many
places where such memory allocation takes place. As soon as all such
incorrect allocations be fixed the cmake option
 -DWITH_PROTECT_STATEMENT_MEMROOT
can be removed and control of memory allocation made on second and
following executions can be turned on only for debug build. Before
every incorrect memory allocation be fixed it makes sense to guard
the checking of memory allocation on read only memory by extra cmake
option else we would get a lot of failing test on buildbot.

Moreover, fixing of all incorrect memory allocations could take pretty
long period of time, so for introducing the feature without necessary
to wait until all places throughout the source code be fixed it makes
sense to add the new cmake option.

- Server aborts when table doesn't have referenced index.
This is caused by 5f09b53b (MDEV-31086).
While iterating the foreign key constraints, we fail to
consider that InnoDB doesn't have referenced index for
it when foreign key check is disabled.

For clang compiler the compiler's flag -Wno-unused-but-set-variable
was set based on compiler version. This approach could result in
false positive detection for presence of compiler option since
only first three groups of digits in compiler version taken into account
and it could lead to inaccuracy in determining of supported compiler's
features.

Correct way to detect options supported by a compiler is to use
the macros  MY_CHECK_CXX_COMPILER_FLAG and to check the result of
variable with prefix have_CXX__
So, to check whether compiler does support the option
 -Wno-unused-but-set-variable
the macros
 MY_CHECK_CXX_COMPILER_FLAG(-Wno-unused-but-set-variable)
should be called and the result variable
 have_CXX__Wno_unused_but_set_variable
be tested for assigned value.

innodb_max_purge_lag_wait_update(): Return immediately if we are
in high_level_read_only mode.

srv_wake_purge_thread_if_not_active(): Relax a debug assertion.
If srv_read_only_mode holds, purge_sys.enabled() will not hold
and this function will do nothing.

trx_t::commit_in_memory(): Remove a redundant condition before
invoking srv_wake_purge_thread_if_not_active().

Spider connection string is a comma-separated parameter definitions,
where each definition is of the form "<param_title> <param_value>",
where <param_value> is quote delimited on both ends, with backslashes
acting as an escaping prefix.

Despite the simple syntax, the existing spider connection string
parser was poorly-written, complex, hard to reason and error-prone,
causing issues like the one described in MDEV-31117. For example it
treated param title the same way as param value when assigning, and
have nonsensical fields like delim_title_len and delim_title.

Thus as part of the bugfix, we clean up the spider comment connection
string parsing, including:

- Factoring out some code from the parsing function
- Simplify the struct `st_spider_param_string_parse`
- And any necessary changes caused by the above changes

The test innodb.row_size_error_log_warnings_3 that was added in
commit 372b0e63 (MDEV-20194)
failed to take into account the earlier adjustment in
commit cf574cf5 (MDEV-27634)
that is specific to many GNU/Linux distributions for the s390x.

trx_undo_write_xid(): Correct an off-by-one error in a debug assertion.

buf_read_page_low(): Remove an error message that could be triggered
by buf_read_ahead_linear() or buf_read_ahead_random().

This is a backport of commit c9eff1a1
from MariaDB Server 10.5.

buf_read_ahead_random(), buf_read_ahead_linear(): Avoid read-ahead
of the last page(s) of ROW_FORMAT=COMPRESSED tablespaces that use
a page size of 1024 or 2048 bytes. We invoke os_file_set_size() on
integer multiples of 4096 bytes in order to be compatible with
the requirements of innodb_flush_method=O_DIRECT regardless of the
physical block size of the underlying storage.

This change must be null-merged to MariaDB Server 10.5 and later.
There, out-of-bounds read-ahead should be handled gracefully
by simply discarding the buffer page that had been allocated.

Tested by: Matthias Leich

When the SQL driver thread goes to wait for room in the parallel slave
worker queue, there was a race where a kill at the right moment could
be ignored and the wait proceed uninterrupted by the kill.

Fix by moving the THD::check_killed() to occur _after_ doing ENTER_COND().

This bug was seen as sporadic failure of the testcase rpl.rpl_parallel
(rpl.rpl_parallel_gco_wait_kill since 10.5), with "Slave stopped with
wrong error code".
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>

Restore code to make InnoDB choose the second transaction as a deadlock
victim if two transactions deadlock that need to commit in-order for
parallel replication. This code was erroneously removed when VATS was
implemented in InnoDB.

Also add a test case for InnoDB choosing the right deadlock victim.
Also fixes this bug, with testcase that reliably reproduces:

MDEV-28776: rpl.rpl_mark_optimize_tbl_ddl fails with timeout on sync_with_master

Note: This should be null-merged to 10.6, as a different fix is needed
there due to InnoDB locking code changes.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>

Remove the exception that InnoDB does not report auto-increment locks waits
to the parallel replication.

There was an assumption that these waits could not cause conflicts with
in-order parallel replication and thus need not be reported. However, this
assumption is wrong and it is possible to get conflicts that lead to hangs
for the duration of --innodb-lock-wait-timeout. This can be seen with three
transactions:

1. T1 is waiting for T3 on an autoinc lock
2. T2 is waiting for T1 to commit
3. T3 is waiting on a normal row lock held by T2

Here, T3 needs to be deadlock killed on the wait by T1.

Note: This should be null-merged to 10.6, as a different fix is needed
there due to InnoDB lock code changes.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>

The test innodb.alter_rename_files rather frequently hangs in
checkpoint_set_now. The test was removed in MariaDB Server 10.5
commit 37e7bde1 when the code that
it aimed to cover was simplified. Starting with MariaDB Server 10.5
the page flushing and log checkpointing is much simpler, handled
by the single buf_flush_page_cleaner() thread.

Let us remove the test to avoid occasional failures. We are not going
to fix the cause of the failure in MariaDB Server 10.4.

Fix issue was earlier fixed by MDEV-31724. Only adding MTR tests.

Field_varstring::get_copy_func() did not take into account
that functions do_varstring1[_mb], do_varstring2[_mb] do not support
compressed data.

Changing the return value of Field_varstring::get_copy_func()
to `do_field_string` if there is a compresion and truncation
at the same time. This fixes the problem, so now it works as follows:
- val_str() uncompresses the data
- The prefix is then calculated on the uncompressed data

Additionally, introducing two new copying functions
- do_varstring1_no_truncation()
- do_varstring2_no_truncation()

Using new copying functions in cases when:
- a Field_varstring with length_bytes==1 is changing to a longer
    Field_varstring with length_bytes==1
- a Field_varstring with length_bytes==2 is changing to a longer
    Field_varstring with length_bytes==2

In these cases we don't care neither of compression nor
of multi-byte prefixes: the entire data gets fully copied
from the source column to the target column as is.

This is a kind of new optimization, but this also was needed
to preserve existing MTR test results.

This is also related to
MDEV-31348 Assertion `last_key_entry >= end_pos' failed in virtual bool
           JOIN_CACHE_HASHED::put_record()

Valgrind exposed a problem with the join_cache for hash joins:
=25636== Conditional jump or move depends on uninitialised value(s)
==25636== at 0xA8FF4E: JOIN_CACHE_HASHED::init_hash_table()
          (sql_join_cache.cc:2901)

The reason for this was that avg_record_length contained a random value
if one had used SET optimizer_switch='optimize_join_buffer_size=off'.

This causes either 'random size' memory to be allocated (up to
join_buffer_size) which can increase memory usage or, if avg_record_length
is less than the row size, memory overwrites in thd->mem_root, which is
bad.

Fixed by setting avg_record_length in JOIN_CACHE_HASHED::init()
before it's used.

There is no test case for MDEV-31893 as valgrind of join_cache_notasan
checks that.
I added a test case for MDEV-31348.

The test case accessed slave-relay-bin.000003 without waiting for the IO
thread to write it first. If the IO thread was slow, this could fail.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>

Revert the old work-around for buggy fdatasync() on Linux ext3. This bug was
fixed in Linux > 10 years ago back to kernel version at least 3.0.
Reviewed-by: Marko Mäkelä <marko.makela@mariadb.com>
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>

This is also related to
MDEV-31348 Assertion `last_key_entry >= end_pos' failed in virtual bool
           JOIN_CACHE_HASHED::put_record()

Valgrind exposed a problem with the join_cache for hash joins:
=25636== Conditional jump or move depends on uninitialised value(s)
==25636== at 0xA8FF4E: JOIN_CACHE_HASHED::init_hash_table()
          (sql_join_cache.cc:2901)

The reason for this was that avg_record_length contained a random value
if one had used SET optimizer_switch='optimize_join_buffer_size=off'.

This causes either 'random size' memory to be allocated (up to
join_buffer_size) which can increase memory usage or, if avg_record_length
is less than the row size, memory overwrites in thd->mem_root, which is
bad.

Fixed by setting avg_record_length in JOIN_CACHE_HASHED::init()
before it's used.

There is no test case for MDEV-31893 as valgrind of join_cache_notasan
checks that.
I added a test case for MDEV-31348.

This reverts commit 6c405904.

This reverts commit b54e4bf0.

- InnoDB aborts when table is dropping the column. This is
caused by 5f09b53b (MDEV-31086).
While iterating the altered table fields, we fail to consider
the dropped columns.

There was two related problems:

(1) Galera node that is defined as a slave to async MariaDB
master at restart might do SST (state stransfer) and
part of that it will copy mysql.gtid_slave_pos table.
Problem is that updates on that table are not replicated
on a cluster. Therefore, table from donor that is not
slave is copied and joiner looses gtid position it was
and start executing events from wrong position of the binlog.
This incorrect position could break replication and
causes node to be dropped and requiring user action.

(2) Slave sql thread might start executing events before
galera is ready (wsrep_ready=ON) and that could also
cause node to be dropped from the cluster.

In this fix we enable replication of mysql.gtid_slave_pos
table on a cluster. In this way all nodes in a cluster
will know gtid slave position and even after SST joiner
knows correct gtid position to start.

Furthermore, we wait galera to be ready before slave
sql thread executes any events to prevent too early
execution.
Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>