MDEV-14711 Assertion `mode == 16 || mode == 12 || !fix_block->page.file_page_was_freed' failed in buf_page_get_gen (rollback requesting a freed undo page)

Problem:
=======
In buf_cur_optimistic_latch_leaves(), requesting a left block with BTR_GET
after releasing current block. But there is no guarantee that left block
could be still available.

Fix:
====

(1) In btr_cur_optimistic_latch_leaves(), replace the BUF_GET with
BUF_GET_POSSIBLY_FREED for fetching left block.
(2) Once InnoDB acquires left block, it should check FIL_PAGE_NEXT with
current block page number. If not, release cursor->left_block and return
false.

Fixed by new  recording test recording

The sporadic test hangs happen because of mutex dealock between innodb
background threads and two test connection executions.
The test sets variable innodb_disallow_writes, which blocks all writes
to filesyste. The test logic is to execute an INSERT, which should hang
because of filesytstem writes are blocked, and through another session
verify by SELECT that this hanging happens. The SELECT session will then
release innodb_disallow_writes blocking.

However, filesystem write  blocking affects also innodb background threads
and they may hang while keeping some other resources locked.
As an example, in one test hang situation, buffer pool access was blocked.
And, if buffer pool is blocked, the test connections will be blocked as well,
and the SELECT session will not be able to continue to release the
innodb_disallow_writes.

The fix in this commit is refactoring of the test logic.
The test will now set first innodb_disallow_writes blocking, and then record
a hash of data directory's filesystem contents. This works as checksum of the
state of data on the datadirectory.

Then some SQL load is tried on both nodes, these sessions will be blocking
due to frozen file system state. The test will have a short sleep to allow
innodb background threads to loop and possibly encounter innodb_disallow_writes
blocking as well.

After the sleep, the test will record file system checksun for the second time,
and then release the innodb_disallow-writes blocking.

Finally, the two checksums are compared, they should be identical to verify that
nothing was written on datadirectory during the test execution.

The checksum is implemented by md5sum hash over all files found in datadirectory
by find command. all these file hashes are hashed together by one more md5sum.

The test therefore depends on md5sum and find. find may work differently with some
OS distributions, e.g. freebsd may be problematic.

Add wait_condition

Problem:
========
dict_load_table_one() doesn't handle the scenario where clustered
index page is FIL_NULL when DICT_ERR_IGNORE_INDEX_ROOT mode
is set.

Fix:
====
InnoDB should set the file_unreadable when it can't find the
clustered index root page.

- Due to commit fe95cb2e (MDEV-16125),
InnoDB master thread does not need to call srv_resume_thread()
and therefore there is no need to wake up the thread.
Due to the above patch, InnoDB should remove the following dead code.

srv_check_activity(): Makes the parameter as in,out and returns the
recent activity value

innobase_active_small(): Removed

srv_active_wake_master_thread(): Removed

srv_wake_master_thread(): Removed

srv_active_wake_master_thread_low(): Removed

Simplify srv_master_thread() and remove switch cases, added the assert.

Replace srv_wake_master_thread() with srv_inc_activity_count()

INNOBASE_WAKE_INTERVAL: Removed

MDEV-14203: rpl.rpl_extra_col_master_myisam, rpl.rpl_slave_load_tmpdir_not_exist failed in buildbot with a warning

Problem:
=======
rpl.rpl_slave_load_tmpdir_not_exist 'stmt' w3 [ fail ]  Found warnings/errors
in server log file!

Test ended at 2017-09-27 20:34:55
[Warning] Master is configured to log replication events with checksum, but
will not send such events to slaves that cannot process them
^ Found warnings in /mnt/buildbot/build/mariadb-10.2.10/mysql-test/var/3/log/mysqld.1.err
ok
Analysis:
========
When slave tries to connect to master 'get_master_version_and_clock' function
is invoked to perform elaborated slave-master handshake. During this process
slave server queries master server, to know if it is checksum aware and at the
same time master is notified about its CRC-awareness. The master's side
instant value of @@global.binlog_checksum is stored in the dump thread's
uservar area as well as cached locally to become known in consensus by master
and slave.

Post hand-shake slave requests master for binlog dump. It sends
'COM_BINLOG_DUMP'. This command is sent to master by 'cli_advanced_command'
call. If there is some temporary network failure during this request_dump
call, 'end_server' is invoked to close the current connection between master
and slave. Upon connection close the dump thread on the master gets terminated
and it clears the 'uservar' data it got through master-slave handshake.

The 'COM_BINLOG_DUMP' command is sent once again without master-slave
handshake. Since the checksum data is not available with new dump thread a
warning gets reported.

Fix:
===
Upon network write error donot attempt reconnect, proceed to master-slave
handshake. This ensures that master is aware of slave's capability to use
checksums.

__pthread_cond_timedwait() in page cleaner hangs if os time moved
backwards.Workaround could be waking up the page cleaner thread in
logs_empty_and_mark_files_at_shutdown(). But there is possibility that
server could hang when server is running. So InnoDB should wake up page
cleaner thread periodically in srv_master_do_idle_tasks().

There can be multiple MLOG_CHECKPOINT record for the same checkpoint.
During recovery, InnoDB could encounter the previous MLOG_CHECKPOINT
for the checkpoint lsn. So the assertion
mlog_checkpoint_lsn <= recovered_lsn is wrong.

* Allocate items on thd->mem_root while refixing vcol exprs
* Make vcol tree changes register and roll them back after the statement is executed.

Explanation:
Due to collation implementation specifics an Item tree could change while fixing.
The tricky thing here is to make it on a proper arena.
It's usually not a problem when a field is deterministic, however, makes a pain vice-versa, during allocation allocating.
A non-deterministic field should be refixed on each statement, since it depends on the environment state.
Changing the tree will be temporary and therefore it should be reverted after the statement execution.

When InnoDB is extending a data file, it is updating the FSP_SIZE
field in the first page of the data file.

In commit 8451e090 (MDEV-11556)
we removed a work-around for this bug and made recovery stricter,
by making it track changes to FSP_SIZE via redo log records, and
extend the data files before any changes are being applied to them.

It turns out that the function fsp_fill_free_list() is not crash-safe
with respect to this when it is initializing the change buffer bitmap
page (page 1, or generally, N*innodb_page_size+1). It uses a separate
mini-transaction that is committed (and will be written to the redo
log file) before the mini-transaction that actually extended the data
file. Hence, recovery can observe a reference to a page that is
beyond the current end of the data file.

fsp_fill_free_list(): Initialize the change buffer bitmap page in
the same mini-transaction.

The rest of the changes are fixing a bug that the use of the separate
mini-transaction was attempting to work around. Namely, we must ensure
that no other thread will access the change buffer bitmap page before
our mini-transaction has been committed and all page latches have been
released.

That is, for read-ahead as well as neighbour flushing, we must avoid
accessing pages that might not yet be durably part of the tablespace.

fil_space_t::committed_size: The size of the tablespace
as persisted by mtr_commit().

fil_space_t::max_page_number_for_io(): Limit the highest page
number for I/O batches to committed_size.

MTR_MEMO_SPACE_X_LOCK: Replaces MTR_MEMO_X_LOCK for fil_space_t::latch.

mtr_x_space_lock(): Replaces mtr_x_lock() for fil_space_t::latch.

mtr_memo_slot_release_func(): When releasing MTR_MEMO_SPACE_X_LOCK,
copy space->size to space->committed_size. In this way, read-ahead
or flushing will never be invoked on pages that do not yet exist
according to FSP_SIZE.

Server auto-sets lower_case_file_system value based on default
datadir's behavior instead of instead of using the directory specified
by the user through the configuration file or command line options.

This patch fixes this problem.

Server auto-sets lower_case_file_system value based on default
datadir's behavior instead of instead of using the directory specified
by the user through the configuration file or command line options.

This patch fixes this problem.

In commit 0f90728b (MDEV-16809)
we introduced the configuration option innodb_log_optimize_ddl
for controlling whether native index creation or table-rebuild
in InnoDB should avoid writing full redo log.

Fungo Wang reported that this option is causing occasional failures.
The reason is that pages may be written to data files in an
inconsistent state. Applying log records to such inconsistent pages
may fail.

The solution is to always invoke PageBulk::finish() before page latches
may be released, to ensure that the page contents is in a consistent
state.

Something similar was implemented in MySQL 8.0.13:
mysql/mysql-server@d1254b947354e0f5b7223b09c521bd85f22e1e31

buf_block_t::skip_flush_check: Remove. Suppressing consistency checks
is a bad idea.

PageBulk::needs_finish(): New predicate: Determine whether
PageBulk::finish() must fix up the page.

PageBulk::init(): Clear PAGE_DIRECTION to ensure that needs_finish()
will hold. We change the field from PAGE_NO_DIRECTION to 0
and back without writing redo log. This trick avoids the need
to introduce any new data member to PageBulk.

PageBulk::insert(): Replace some high-level accessors to bypass
debug assertions related to PAGE_HEAP_TOP that we will be violating
until finish() has been executed.

PageBulk::finish(): Tolerate m_rec_no==0. We must invoke this also
on an empty page, to ensure that PAGE_HEAP_TOP is initialized.

PageBulk::commit(): Always invoke finish().

PageBulk::release(), BtrBulk::pageSplit(), BtrBulk::storeExt(),
BtrBulk::finish(): Invoke PageBulk::finish().

page_simple_validate_old(), page_simple_validate_new():
Require PAGE_N_DIR_SLOTS to be at least 2.

MDEV-22721 (commit eba2d10a)
inadvertently introduced an infinite loop.

page_validate(): Remove the infinite loop.

-Wl,-z,relro,-z,now are linker flags and should
be checked as such.

TODO: perform module, exe shared checks separately
rather than a pure linker check.

An oveflow was happening on windows because on Windows sizeof(ulong) is 4 bytes
while it is 8 bytes on Linux.
Switched avg_frequency and avg length for column statistics to ulonglong.
Switched avg_frequency for index statistics to ulonglong.

The only InnoDB change between MySQL 5.7.30 and MySQL 5.7.31
that is applicable to MariaDB Server was applied in
commit 8d061996 (MDEV-23161).

The only InnoDB changes between Percona XtraDB Server 5.6.47-87.0
and 5.6.48-88.0 are related to InnoDB changes between MySQL 5.6.47
and MySQL 5.6.48, which we had already applied.

There were no InnoDB changes between MySQL 5.6.48 and MySQL 5.6.49.

This issue was originally reported by Fungo Wang, along with a fix, as
MySQL Bug #98990.

His suggested fix was applied as part of
mysql/mysql-server@a003fc373d1adb3ccea353b5d7d83f6c4c552383
and released in MySQL 5.7.31.

i_s_metrics_fill(): Add the missing call to Field::set_notnull(),
and simplify some code.

- i_s_fts_index_cache_fill() should take shared lock of fts cache
before accessing index cache to avoid reading stale data.

- Problem is that test case creates iblogfile* files. So existing
ibdata pages could point to future LSN. Fix is that taking the
backup of data before iblogfile* creation and apply it before
exiting the test case.

MDEV-22890 DEADLOCK of threads detected: row0sel.cc S-LOCK / btr0cur.cc S-LOCK / row0quiesce.cc X-LOCK

Problem:
=======
- Read operations are always allowed to hold a secondary index leaf
latch and then look up the corresponding clustered index record.
Flush table operation acquires secondary index latch while holding
a clustered index latch. It leads to deadlock violation.

Fix:
====
- Flush table operation should acquire secondary index before taking
clustered index to avoid deadlock violation with select operation.

Only install wsrep scripts and links if WSREP_ON is actually set

MDEV-22463: Element_type &Bounds_checked_array<Item *>::operator[](size_t) [Element_type = Item *]: Assertion `n < m_size' failed.

Allocate space for fields inside the window function (arguments, PARTITION BY and ORDER BY clause)
in the ref pointer array. All fields inside the window function are part of the temporary
table that is required for the window function computation.

MDEV-22058: Assertion `!is_set() || (m_status == DA_OK_BULK && is_bulk_op())' failed in Diagnostics_area::set_ok_status

Error state is not stored in check_and_do_in_subquery_rewrites() when there is
illegal combination of optimizer switches. So all the functions eventually
return false. Thus the assetion failure.

The client can only find out if the server has disconnected when it tries to
read or send something. If the server gets disconnected before
send_client_reply_packet(), the client will try sending authentication
information but it will fail. But, if the client is fast enough to send
autentication information before disconnecting, it will notice that when
reading the ok packet. So the client can fail on read or on write.
It is unpredictable because, the process are unsynchronized and this
could happen in any order.