The function ibuf_remove_free_page() may be called while the caller
is holding several mutexes or rw-locks. Because of this, this
housekeeping loop may cause performance glitches for operations that
involve tables that are stored in the InnoDB system tablespace.
Also deadlocks might be possible.

The worst impact of all is that due to the mutexes being held, calls to
log_free_check() had to be skipped during this housekeeping.
This means that the cyclic InnoDB redo log may be overwritten.
If the system crashes during this, it would be unable to recover.

The entry point to the problematic code is ibuf_free_excess_pages().
It would make sense to call it before acquiring any mutexes or rw-locks,
in any 'pessimistic' operation that involves the system tablespace.

fseg_create_general(), fseg_alloc_free_page_general(): Do not call
ibuf_free_excess_pages() while potentially holding some latches.

ibuf_remove_free_page(): Do call log_free_check(), like every operation
that is about to generate redo log should do.

ibuf_free_excess_pages(): Remove some assertions that are replaced
by stricter assertions in the log_free_check() that is now called by
ibuf_remove_free_page().

row_mtr_start(): New function, to perform necessary preparations when
starting a mini-transaction for row operations. For pessimistic operations
on secondary indexes that are located in the system tablespace,
this includes calling ibuf_free_excess_pages().

row_undo_ins_remove_sec_low(), row_undo_mod_del_mark_or_remove_sec_low(),
row_undo_mod_del_unmark_sec_and_undo_update(): Call row_mtr_start().

row_ins_sec_index_entry(): Call ibuf_free_excess_pages() if the operation
may involve allocating pages and change buffering in the system tablespace.

row_upd_sec_index_entry(): Slightly refactor the code. The
delete-marking of the old entry is done in-place. It could be
change-buffered, but the old code should be unlikely to have
invoked ibuf_free_excess_pages() in this case.

Fix minor typo.

This bug was a regression caused by MDEV-12698.

On non-leaf pages, the delete-mark flag in the node pointer records is
basically garbage. (Delete-marking only makes sense at the leaf level
anyway. The purpose of the delete-mark is to tell MVCC, locking and purge
that a leaf-level record does not exist in the READ UNCOMMITTED view,
but it used to exist.)
Node pointer records and non-leaf pages are glue that attaches multiple
leaf pages to an index. This glue is supposed to be transparent to the
transactional layer.

When a page is split, InnoDB creates a node pointer record out of the
child page record that the cursor is positioned on. The node pointer record
for the parent page will be a copy of the child page record, amended with
the child page number. If the child page record happened to carry the
delete-mark flag, then the node pointer record would also carry this flag
(even though the flag makes no sense outside child pages).

(On a related note, for the first node pointer record in the first
node pointer page of each tree level, if the MIN_REC_FLAG is set,
the rest of the record contents (except the child page number)
is basically garbage. From this garbage you could deduce at which point
the child was originally split.)

page_scan_method_t: Replace with bool, as there are only 2 values.

dict_stats_scan_page(): Replace the parameter scan_method with is_leaf.
Ignore the bogus (garbage) delete-mark flag if !is_leaf.

- Add include/index_merge*. Upstream has different files than MariaDB,
  use copies theirs, not ours.
- There was a prblem with running "DDL-like" commands with binlog=ON:
  MariaDB sets binlog_format=STATEMENT for the duration of such command
  to prevent RBR replication from catching (and replicating) updates to
  system tables.
  However, MyRocks tries to prevent any writes to MyRocks tables with
  binlog_format!=ROW.
- Added exceptions for DDL-type commands (ANALYZE TABLE, OPTIMIZE TABLE)
- Added special handling for "LOCK TABLE(s) myrocks_table WRITE".

 # ib_logfile0 expecting FOUND
-FOUND 3 /public|gossip/ in ib_logfile0
+FOUND 2 /public|gossip/ in ib_logfile0

The most plausible explanation for this difference
should be that the redo log payload grew was so big that
one of the strings (for writing the undo log record,
clustered index record, and secondary index record)
was written to ib_logfile1 instead of ib_logfile0.

Let us run the test with --innodb-log-files-in-group=1 so that
only a single log file will be used.

The MySQL 5.6.36 merge (commit 0af98182
in MariaDB Server 10.0.31, 10.1.24, 10.2.7) introduced a change from
Oracle:
Bug#25551311 BACKPORT BUG #23517560 REMOVE SPACE_ID RESTRICTION
FOR UNDO TABLESPACES

Some debug assertions in MariaDB 10.2 were still assuming that the
InnoDB undo tablespace IDs start from 1. With the above mentioned
change, the undo tablespace IDs must be contiguous and nonzero.

In key rotation, we must initialize unallocated but previously
initialized pages, so that if encryption is enabled on a table,
all clear-text data for the page will eventually be overwritten.
But we should not rotate keys on pages that were never allocated
after the data file was created.

According to the latching order rules, after acquiring the
tablespace latch, no page latches of previously allocated user pages
may be acquired. So, key rotation should check the page allocation
status after acquiring the page latch, not before. But, the latching
order rules also prohibit accessing pages that were not allocated first,
and then acquiring the tablespace latch. Such behaviour would indeed
result in a deadlock when running the following tests:
encryption.innodb_encryption-page-compression
encryption.innodb-checksum-algorithm

Because the key rotation is accessing potentially unallocated pages, it
cannot reliably check if these pages were allocated. It can only check
the page header. If the page number is zero, we can assume that the
page is unallocated.

fil_crypt_rotate_pages(): Skip pages that are known to be uninitialized.

fil_crypt_rotate_page(): Detect uninitialized pages by FIL_PAGE_OFFSET.
Page 0 is never encrypted, and on other pages that are initialized,
FIL_PAGE_OFFSET must contain the page number.

fil_crypt_is_page_uninitialized(): Remove. It suffices to check the
page number field in fil_crypt_rotate_page().

xdes_get_descriptor_const(): New function, to get read-only access to
the allocation descriptor.

fseg_page_is_free(): Only acquire a shared latch on the tablespace,
not an exclusive latch. Calculate the descriptor page address before
acquiring the tablespace latch. If the page number is out of bounds,
return without fetching any page. Access only one descriptor page.

fsp_page_is_free(), fsp_page_is_free_func(): Remove.
Use fseg_page_is_free() instead.

fsp_init_file_page(): Move the debug parameter into a separate function.

btr_validate_level(): Remove the unused variable "seg".

The parameter --innodb-sync-debug, which is disabled by default,
aims to find potential deadlocks in InnoDB.

When the parameter is enabled, lots of tests failed. Most of these
failures were due to bogus diagnostics. But, as part of this fix,
we are also fixing a bug in error handling code and removing dead
code, and fixing cases where an uninitialized mutex was being
locked and unlocked.

dict_create_foreign_constraints_low(): Remove an extraneous
mutex_exit() call that could cause corruption in an error handling
path. Also, do not unnecessarily acquire dict_foreign_err_mutex.
Its only purpose is to control concurrent access to
dict_foreign_err_file.

row_ins_foreign_trx_print(): Replace a redundant condition with a
debug assertion.

srv_dict_tmpfile, srv_dict_tmpfile_mutex: Remove. The
temporary file is never being written to or read from.

log_free_check(): Allow SYNC_FTS_CACHE (fts_cache_t::lock)
to be held.

ha_innobase::inplace_alter_table(), row_merge_insert_index_tuples():
Assert that no unexpected latches are being held.

sync_latch_meta_init(): Properly initialize dict_operation_lock_key
at SYNC_DICT_OPERATION. dict_sys->mutex is SYNC_DICT, and
the now-removed SRV_DICT_TMPFILE was wrongly registered at
SYNC_DICT_OPERATION.

buf_block_init(): Correctly register buf_block_t::debug_latch.
It was previously misleadingly reported as LATCH_ID_DICT_FOREIGN_ERR.

latch_level_t: Correct the relative latching order of
SYNC_IBUF_PESS_INSERT_MUTEX,SYNC_INDEX_TREE and
SYNC_FILE_FORMAT_TAG,SYNC_DICT_OPERATION to avoid bogus failures.

row_drop_table_for_mysql(): Avoid accessing btr_defragment_mutex
if the defragmentation thread has not been started. This is the
case during fts_drop_orphaned_tables() in recv_recovery_rollback_active().

fil_space_destroy_crypt_data(): Avoid acquiring fil_crypt_threads_mutex
when it is uninitialized. We may have created crypt_data before the
mutex was created, and the mutex creation would be skipped if
InnoDB startup failed or --innodb-read-only was specified.

InnoDB stopped generating the MLOG_INIT_FILE_PAGE record in
MySQL 5.7.5. Starting with MySQL 5.7.9 (which was imported to
MariaDB Server 10.2.2), the InnoDB redo log format tag prevents
crash recovery from old-format redo logs.

Remove the dead code for dealing with MLOG_INIT_FILE_PAGE.

The previous fix (commit dcdc1c6d)
should have removed the assertion from log_close(), because every
caller that requires this assertion is already asserting that log
writes are allowed. When fil_names_clear() is called, it must be
able to write the MLOG_CHECKPOINT records. The purpose of the debug
variable recv_no_log_write is to prevent the creation of page-level
redo log records, or modifications to persistent data.

- Remove the merge error
- Update test results

Add suppressions for the read and decompression errors.
This may be 10.3 specific and related to MDEV-13536 which increases
purge activity. But it does not hurt to suppress rarely occurring
and plausible error messages for this fault-injection test already in 10.2.

MDEV-13570 Assertion failure !srv_read_only_mode in --innodb-read-only shutdown when buf_resize_thread is active

logs_empty_and_mark_files_at_shutdown(): Skip the debug assertion
when the buf_resize_thread is active.

MDEV-13575 On failure, Mariabackup --backup --safe-slave-backup may forget to START SLAVE SQL_THREAD

backup_release(): New function, refactored from backup_finish().
Release some resources that may have been acquired by backup_startup()
and should be released even after a failed operation.

xtrabackup_backup_low(): Refactored from xtrabackup_backup_func().

xtrabackup_backup_func(): Always call backup_release() after calling
backup_start().

The test mariabackup.incremental_backup revealed a memory leak
in have_queries_to_wait_for(). The problem is that
xb_mysql_query() is being invoked with bool use_result=true
but the result is not being freed by mysql_store_result().
There are similar leaks in other functions.

have_queries_to_wait_for(): Invoke mysql_free_result() to
clean up after the mysql_store_result() that was invoked
by xb_mysql_query().

select_incremental_lsn_from_history(): Plug the leak on failure.

kill_long_queries(): Plug the memory leak.
(This function always leaked memory when it was called.)

have_queries_to_wait_for(), kill_long_queries(): Declare and initialize
variables in one go.

The fix broke mariabackup --prepare --incremental.

The restore of an incremental backup starts up (parts of) InnoDB twice.
First, all data files are discovered for applying .delta files. Then,
after the .delta files have been applied, InnoDB will be restarted
more completely, so that the redo log records will be applied via the
buffer pool.

During the first startup, the buffer pool is not initialized, and thus
trx_rseg_get_n_undo_tablespaces() must not be invoked. The apply of
the .delta files will currently assume that the --innodb-undo-tablespaces
option correctly specifies the number of undo tablespace files, just
like --backup does.

The second InnoDB startup of --prepare for applying the redo log will
properly invoke trx_rseg_get_n_undo_tablespaces().

enum srv_operation_mode: Add SRV_OPERATION_RESTORE_DELTA for
distinguishing the apply of .delta files from SRV_OPERATION_RESTORE.

srv_undo_tablespaces_init(): In mariabackup --prepare --incremental,
in the initial SRV_OPERATION_RESTORE_DELTA phase, do not invoke
trx_rseg_get_n_undo_tablespaces() because the buffer pool or the
redo logs are not available. Instead, blindly rely on the parameter
--innodb-undo-tablespaces.

If previous tests opened system tables, the test could fail because
it crashes the server. Added FLUSH TABLES to avoid it

fails with ERROR_INVALID_FUNCTION

This DeviceIoControl seems to happen on different boxes from time to time,
and there is not much user can do about it.
Instead of error, log a single INFO message, so it does not disturb users
much.

srv_undo_tablespaces_init(): In Mariabackup backup and restore modes,
do initialize the array of undo_tablespace_ids[].

MDEV-11240: Server crashes in check_view_single_update or Assertion `derived->table' failed in mysql_derived_merge_for_insert

Before "merge" view shoud be inited to maintaing transitive attributes like "multitable".

don't assume that the table always has a primary key,
head->s->primary_key might be MAX_KEY, which won't start keyread.

tabtyp was defined under ODBC_SUPPORT, but used
outside of it too (under JDBC_SUPPORT).

(socket connection ignores the port and CONNECT connects to the wrong host)

we'll copy it from 5.7 when we'll need it

Apply this patch from upstream:

commit 2c8deddfb67f1cd41ea3d1ac95aa1aa9327e3406
Author: Yoshinori Matsunobu <yoshinorim@users.noreply.github.com>
Date:   Tue Aug 15 16:21:58 2017 -0700

    Set exclusive_manual_compaction = false on manual compactions

    Summary:
    Combining exclusive manual compaction and
    non-exclusive manual compaction may hit rocksdb assertion errors.
    This diff makes all MyRocks internal manual compactions non exclusive.
    Closes https://github.com/facebook/mysql-5.6/pull/682

    Differential Revision: D5633619

    Pulled By: yoshinorim

    fbshipit-source-id: a90786d

The bug was caused by a defect of the patch for the bug 11081.
The patch was actually a port of the fix this bug from the mysql
code line. Later a correction of this fix was added to the
mysql code. Here's the comment this correction was provided with:

  Bug#16499751: Opening cursor on SELECT in stored procedure causes segfault
  This is a regression from the fix of bug#14740889.
  The fix started using another set of expressions as the source for
  the temporary table used for the materialized cursor. However,
  JOIN::make_tmp_tables_info() calls setup_copy_fields() which creates
  an Item_copy wrapper object on top of the function being selected.
  The Item_copy objects were not properly handled by create_tmp_table -
  they were simply ignored. This patch creates temporary table fields
  based on the underlying item of the Item_copy objects.

The test case for the bug 13346 was taken from mdev-13380.

The test mis-used MTR's "restart the server if it crashed or exited"
feature to try starting MyRocks plugin with invalid arguments.

Changed the test to use the --default-storage-engine=myisam which
allows the server to start when MyRocks fails to start.

This removes the need to "start the server with the arguments which
will caused it to fail to start", and so removes the race conditions
with MTR server restart code and  mysqld.*.expect file.

row_ins_check_foreign_constraint(): On timeout,
return DB_LOCK_WAIT_TIMEOUT instead of DB_LOCK_WAIT,
so that the lock wait will be properly terminated.
Also, replace some redundant assignments.

It looks like this bug was introduced in MySQL 5.7.8 by:

    commit a97f6b91227c7e0fc3151cfe5421891e79c12d19
    Author: Annamalai Gurusami <annamalai.gurusami@oracle.com>
    Date:   Tue Jun 9 16:02:31 2015 +0530

        Bug #20953265 INNODB: FAILING ASSERTION: RESULT != FTS_INVALID

MDEV-13498 is a performance regression that was introduced in MariaDB 10.2.2
by commit fec844ac
which introduced some Galera-specific conditions that were being
evaluated even if the write-set replication was not enabled.

MDEV-13246 Stale rows despite ON DELETE CASCADE constraint
is a correctness regression that was introduced by the same commit.

Especially the subcondition
	!(parent && que_node_get_type(parent) == QUE_NODE_UPDATE)
which is equivalent to
	!parent || que_node_get_type(parent) != QUE_NODE_UPDATE
makes little sense. If parent==NULL, the evaluation would proceed to the
std::find() expression, which would dereference parent. Because no SIGSEGV
was observed related to this, we can conclude that parent!=NULL always
holds. But then, the condition would be equivalent to
	que_node_get_type(parent) != QUE_NODE_UPDATE
which would not make sense either, because the std::find() expression
is actually assuming the opposite when casting parent to upd_node_t*.

It looks like this condition never worked properly, or that
it was never properly tested, or both.

wsrep_must_process_fk(): Helper function to check if FOREIGN KEY
constraints need to be processed. Only evaluate the costly std::find()
expression when write-set replication is enabled.

Also, rely on operator<<(std::ostream&, const id_name_t&) and
operator<<(std::ostream&, const table_name_t&) for pretty-printing
index and table names.

row_upd_sec_index_entry(): Add !wsrep_thd_is_BF() to the condition.
This is applying part of "Galera MW-369 FK fixes"
https://github.com/codership/mysql-wsrep/commit/f37b79c6dab101310a45a9e8cb23c0f98716da52
that is described by the following part of the commit comment:
    additionally: skipping wsrep_row_upd_check_foreign_constraint if thd has
    BF, essentially is applier or replaying
    This FK check would be needed only for populating parent row FK keys
    in write set, so no use for appliers

trx_set_rw_mode(): Check the flag high_level_read_only instead
of testing srv_force_recovery (innodb_force_recovery) directly.
There is no need to prevent the creation of read-write transactions
if innodb_force_recovery=3 is used. Yes, in that mode any recovered
incomplete transactions will not be rolled back, but these transactions
will continue to hold locks on the records that they have modified.
If the new read-write transactions hit conflicts with already existing
(possibly recovered) transactions, the lock wait timeout mechanism
will work just fine.