Ever since MDEV-10813 cleaned up InnoDB use of atomic memory operations
and made buf_block_fix() an atomic operation, some conditions around
buf_block_fix() have been unnecessary.

The bug was fixed by the patch for the bug mdev-13780.

It's better to prohibit pushdown of conditions that involve
regexp_substr() and regexp_replace() into materialized derived
tables / views until proper implementations of the get_copy()
virtual method are provided for those functions.

The support of embedded CTEs was not correct in the cases when
embedded CTEs were used multiple times. The problems occurred with
both non-recursive (bug mdev-13780) and recursive (bug mdev-14184)
embedded CTEs.

in joined table + GROUP BY + GROUP_CONCAT + HAVING + ORDER BY
[by field from HAVING] + 1 row expected

The fix is actually a port of the fix for bug #17055185 from
mysql code line (see commit f289aeeef0743508ff87211084453b3b88a6d017
by Mithun C Y into mysql-5.6). The test case for the bug #17055185
was also ported.

- FB/MySQL 5.6' MyRocks has START TRANSACTION WITH CONSISTENT
  ROCKSDB SNAPSHOT, which returns binlog position.

- MariaDB has a cross-engine START TRANSACTION WITH CONSISTENT
  SNAPSHOT. It can be used for the same purpose. Binlog position
  can be obtained from Binlog_snapshot_file/position status vars.

os_file_set_size(): If posix_fallocate() returns EINVAL, fall back
to writing zero bytes to the file. Also, remove some error log output,
and make it possible for a server shutdown to interrupt the fall-back
code.

MariaDB 10.2 used to handle the EINVAL return value from posix_fallocate()
before commit b731a5bc
which refactored os_file_set_size() to try posix_fallocate().

Why is the EINVAL returned? The GNU posix_fallocate() function
would first try the fallocate() system call, which would return
-EOPNOTSUPP for many file systems (notably, not ext4). Then, it
would fall back to extending the file one block at a time by invoking
pwrite(fd, "", 1, offset) where offset is 1 less than a multiple of
the file block size. This would fail with EINVAL if the file is in
O_DIRECT mode, because O_DIRECT requires aligned operation.

The failing test was main.gis-json

- Expand paths also for jemalloc
- Test also if tcmalloc or jemalloc is in /usr/lib64
- Take into account that .so has a version
- Remove automatic adding of flavors ( _minial, _debug). Better to
  have user specify these directly
- Changed documentation link to MariaDB
- Don't give extra error if mysqld_safe_helper doesn't exist

Also don't abort if global_status_var.global_memory_used != 0 on not
normal exit as then it's likely that not all memory is released.

MDEV-13568: Purge is not blocked by LOCK TABLES. Should it?

MDEV-13893/MDEV-12699: Crash recovery of corrupted or non-decryptable
pages is broken.

Signed-off-by: Daniel Black <daniel@linux.vnet.ibm.com>

When MariaDB 10.1.0 introduced table options for encryption and
compression, it unnecessarily changed
ha_innobase::check_if_supported_inplace_alter() so that ALGORITHM=COPY
is forced when these parameters differ.

A better solution is to move the check to innobase_need_rebuild().
In that way, the ALGORITHM=INPLACE interface (yes, the syntax is
very misleading) can be used for rebuilding the table much more
efficiently, with merge sort, with no undo logging, and allowing
concurrent DML operations.

If InnoDB or XtraDB recovered committed transactions at server
startup, but the processing of recovered transactions was
prevented by innodb_read_only or by innodb_force_recovery,
an assertion would fail at shutdown.

This bug was originally reproduced when Mariabackup executed
InnoDB shutdown after preparing (applying redo log into) a backup.

trx_free_prepared(): Allow TRX_STATE_COMMITTED_IN_MEMORY.

trx_undo_free_prepared(): Allow any undo log state. For transactions
that were resurrected in TRX_STATE_COMMITTED_IN_MEMORY
the undo log state would have been reset by trx_undo_set_state_at_finish().

Forgot to put the updated rocksdb.result in

Downscale rocksdb.add_index_inplace_sstfilewriter to be 10x smaller

Fix a race condition in the testcase.

ReadFile/WriteFile operations.

Innodb opens files with FILE_FLAG_OVERLAPPED. lpNumberOfBytesRead/Written
are documented to be potentially inaccurate in this case,
(possibly even if async operations complete synchronously?)

The fix is to always pass NULL for the correspondng parameters,
as recommended by  MSDN. Read the actual counts with
GetQueuedCompletionStatus() or GetOverlappedResult().

os_file_get_size(): Use fstat() instead of calling lseek() 3 times.
In this way, concurrent calls to this function should not interfere
with each other.

Suggested by Vladislav Vaintroub.

The predicate page_is_root() would not hold if btr_create() fails
before the root page is fully initialized. Move the debug assertion
from btr_free_root_invalidate() to its other caller,
btr_free_if_exists(). In that caller, we actually already checked
for page_is_root().

os_file_set_size(): Sometimes the file already is large enough.
Avoid calling posix_fallocate() with a non-positive argument.
Also, add a missing space to an error message.

Adjust and enable rocksdb.2pc_group_commit test

With this patch, parameters passed to posix_fallocate() will be
the same as they were prior to refactoring in  commit b731a5bc

In particular, 'offset' parameter for posix_fallocate is again current_file_size
and 'length' is new_file_size - current_file_size.

This seems to fix crashes on ancient Linux (kernel 2.6).