There is only one purge_sys. Allocate it statically in order to avoid
dereferencing a pointer whenever accessing it. Also, align some
members to their own cache line in order to avoid false sharing.

purge_sys_t::create(): The deferred constructor.

purge_sys_t::close(): The early destructor.

undo::Truncate::create(): The deferred constructor.
Because purge_sys.undo_trunc is constructed before the start-up
parameters are parsed, the normal constructor would copy a
wrong value of srv_purge_rseg_truncate_frequency.

TrxUndoRsegsIterator: Do not forward-declare an inline constructor,
because the static construction of purge_sys.rseg_iter would not have
access to it.

trx_purge(): Remove the parameter limit or batch_size, which is
always passed as srv_purge_batch_size.

trx_purge_attach_undo_recs(): Remove the parameters purge_sys, batch_size.
Refer to srv_purge_batch_size.

trx_purge_wait_for_workers_to_complete(): Remove the parameter purge_sys.

Before MDEV-12288 in MariaDB 10.3.1, InnoDB used to partition
the persistent transaction undo log into insert_undo and update_undo.

MDEV-12288 repurposes the update_undo as the single undo log.
In order to support an upgrade from earlier MariaDB versions,
the insert_undo is recovered in data structures, called old_insert.

An assertion failure occurred in TrxUndoRsegsIterator::set_next()
when an incomplete transaction was recovered with both insert_undo
and update_undo log. This could be easily demonstrated by starting
./mysql-test-run --manual-gdb innodb.read_only_recovery
in MariaDB 10.2, and after the first kill, start up the MariaDB 10.3
server with the same parameters.

The problem is that MariaDB 10.3 would roll back the recovered
transaction, and finally "commit" it twice (with all changes to
data rolled back), both insert_undo and update_undo with the same
commit end identifier (trx->no).

Our fix is to introduce a "commit number" that comprises two components:
(trx->no << 1 | !old_insert). In this way, the assertion in the purge
subsystem can be relaxed so that only the trx->no component must match.

TrxUndoRsegs::append(): Remove.

TrxUndoRsegsIterator::set_next(): Add a debug assertion that
demonstrates that the merging of rollback segments never occurs.
Since MDEV-12289 or earlier, MariaDB 10.2 will not make any
temporary undo log accessible to the purge subsystem.
(Also MySQL 5.7 would skip the purge of any undo log for
temporary tables, but not before parsing and buffering those
temporary undo log records.)

Construct directly from trx_rseg_t&.
push_back(), size(): Remove.

Also, remove the field undo_rseg_space.
Apparently its purpose was to avoid problems with
temporary undo logs, which MySQL 5.7 unnecessarily adds to
the purge system. (Temporary undo log records are not purged.)
MariaDB 10.2 fixed this in MDEV-12289 or earlier.

purge_iter_t::operator<=(): Ordering comparison.
This replaces trx_purge_check_limit() with the difference that
we are not comparing undo_rseg_space. (In MariaDB, temporary
undo logs do not enter the purge subsystem at all.)

purge_sys_t::done: Remove. This was not used for anything.

purge_sys_t::tail: Renamed from purge_sys_t::iter.

purge_sys_t::head: Renamed from purge_sys_t::limit.

Merge pull request #364

Regression introducted in c2118a08 where LOCK_thd_data was moveed
to LOCK_thd_kill

-DWITH_ASAN can be used as well now, on x64

Fix many clang-cl warnings.

elements of BIGINT or YEAR type in the IN list reaches in_predicate_conversion_threshold

The bug appears at the prepare stage when IN-predicate with the long list
of values is converted into IN-subquery. It happens because values in the
right operand of the IN-predicate that have BIGINT or YEAR types are converted
into the Item_int_with_ref.
To fix it in the procedure Item_func_in::create_value_list_for_tvc
real_item() is taken for each value in the right operand of the IN-predicate.

This is based on a prototype by
Thirunarayanan Balathandayuthapani <thiru@mariadb.com>.

Binlog and Galera write-set replication information was written into
TRX_SYS page on each commit. Instead of writing to the TRX_SYS during
normal operation, InnoDB can make use of rollback segment header pages,
which are already being written to during a commit.

The following list of fields in rollback segment header page are added:
    TRX_RSEG_BINLOG_OFFSET
    TRX_RSEG_BINLOG_NAME (NUL-terminated; empty name = not present)
    TRX_RSEG_WSREP_XID_FORMAT (0=not present; 1=present)
    TRX_RSEG_WSREP_XID_GTRID
    TRX_RSEG_WSREP_XID_BQUAL
    TRX_RSEG_WSREP_XID_DATA

trx_sys_t: Introduce the fields
recovered_binlog_filename, recovered_binlog_offset, recovered_wsrep_xid.

To facilitate upgrade from older mysql or mariaDB versions, we will read
the information in TRX_SYS page. It will be overridden by the
information that we find in rollback segment header pages.

Mariabackup --prepare will read the metadata from the rollback
segment header pages via trx_rseg_array_init(). It will still
not read any undo log pages or recover any transactions.

my_atomic_load32() expects a pointer to non-const on Windows.

Fixes this report:
==3165==ERROR: AddressSanitizer: use-after-poison on address 0x61e0000270a0 at pc 0x00000114b78c bp 0x7f15d65fe120 sp 0x7f15d65fd8d0
WRITE of size 1366 at 0x61e0000270a0 thread T28
    #0 0x114b78b in __asan_memcpy fun/cpp_projects/llvm_toolchain/llvm/projects/compiler-rt/lib/asan/asan_interceptors_memintrinsics.cc:23
    #1 0x208208d in TABLE::init(THD*, TABLE_LIST*) work/mariadb/sql/table.cc:4662:3
    #2 0x19df85b in open_table(THD*, TABLE_LIST*, Open_table_context*) work/mariadb/sql/sql_base.cc:1993:10
    #3 0x19eb968 in open_and_process_table(THD*, LEX*, TABLE_LIST*, unsigned int*, unsigned int, Prelocking_strategy*, bool, Open_table_context*) work/mariadb/sql/sql_base.cc:3483:14
    #4 0x19e7c05 in open_tables(THD*, DDL_options_st const&, TABLE_LIST**, unsigned int*, unsigned int, Prelocking_strategy*) work/mariadb/sql/sql_base.cc:4001:14
    #5 0x19f4dac in open_and_lock_tables(THD*, DDL_options_st const&, TABLE_LIST*, bool, unsigned int, Prelocking_strategy*) work/mariadb/sql/sql_base.cc:4879:7
    #6 0x1627263 in open_and_lock_tables(THD*, TABLE_LIST*, bool, unsigned int) work/mariadb/sql/sql_base.h:487:10
    #7 0x1c3839c in mysql_execute_command(THD*) work/mariadb/sql/sql_parse.cc:5113:13
    #8 0x1c1b72c in mysql_parse(THD*, char*, unsigned int, Parser_state*, bool, bool) work/mariadb/sql/sql_parse.cc:7980:18
    #9 0x1c13464 in handle_bootstrap_impl(THD*) work/mariadb/sql/sql_parse.cc:1044:5
    #10 0x1c11ff7 in do_handle_bootstrap(THD*) work/mariadb/sql/sql_parse.cc:1096:3
    #11 0x1c11d14 in handle_bootstrap work/mariadb/sql/sql_parse.cc:1079:3
    #12 0x115a6ae in __asan::AsanThread::ThreadStart(unsigned long, __sanitizer::atomic_uintptr_t*) fun/cpp_projects/llvm_toolchain/llvm/projects/compiler-rt/lib/asan/asan_thread.cc:259
    #13 0x7f15fe1407fb in start_thread (/lib/x86_64-linux-gnu/libpthread.so.0+0x77fb)
    #14 0x7f15fbb64b5e in clone /build/glibc-itYbWN/glibc-2.26/misc/../sysdeps/unix/sysv/linux/x86_64/clone.S:95

trx_sys_t::rseg_history_len: Make private, and clarify the
documentation.

trx_sys_t::history_size(): Read rseg_history_len.

trx_sys_t::history_insert(), trx_sys_t::history_remove(),
trx_sys_t::history_add(): Update rseg_history_len.

        sql_yacc_ora.yy fixed.

MDEV 15105 "Bytes lost and Assertion `global_status_var.global_memory_used == 0' fails on shutdown after attempts
to LOCK/RENAME sequence"

MDEV-12887 UT_LIST_GET_LEN(trx->lock.trx_locks) == 0 when mysqldump
sequence

srv_conc_t::n_active: Correct the comment, and remove an
assertion that trivially holds now that the type is unsigned.

Disable the test encryption.innodb_encryption-page-compression
because the wait_condition would seem to time out deterministically.
MDEV-14814 has to be addressed in 10.2 separately.

Datafile::validate_first_page(): Do not invoke
page_size_t::page_size_t(flags) before validating the tablespace flags.
This avoids a crash in MDEV-15333 innodb.restart test case.
FIXME: Reduce the number of error messages. The first one is enough.

This performance regression was introduced in the MariaDB 10.1
file format incompatibility bug fix MDEV-11623 (MariaDB 10.1.21
and MariaDB 10.2.4) and partially fixed in MariaDB 10.1.25 in
MDEV-12610 without adding a regression test case.

On a normal startup (without crash recovery), InnoDB should not read
every .ibd data file, because this is slow. Like in MySQL, for now,
InnoDB will still open every data file (without reading), and it
will read every .ibd file for which an .isl file exists, or the
DATA DIRECTORY attribute has been specified for the table.

The test case shuts down InnoDB, moves data files, replaces them
with garbage, and then restarts InnoDB, expecting no messages to
be issued for the garbage files. (Some messages will for now be
issued for the table that uses the DATA DIRECTORY attribute.)
Finally, the test shuts down the server, restores the old data files,
and restarts again to drop the tables.

fil_open_single_table_tablespace(): Remove the condition on flags,
and only call fsp_flags_try_adjust() if validate==true
(reading the first page has been requested). The only caller with
validate==false is at server startup when we are processing all
records from SYS_TABLES. The flags passed to this function are
actually derived from SYS_TABLES.TYPE and SYS_TABLES.N_COLS,
and there never was any problem with SYS_TABLES in MariaDB 10.1.
The problem that MDEV-11623 was that incorrect tablespace flags
were computed and written to FSP_SPACE_FLAGS.

Note: Linux only

Core dumps of large buffer pool pages take time and space
and pose potential data expose in scenarios where data-at-rest
encryption is deployed.

Here we use madvise(MADV_DONT_DUMP) on large memory allocations
used by the innodb buffer pool, log_sys and recv_sys. The effect
of this system call is that these memory areas will not appear in
a core dump. Data from these buffers is rarely useful in fault
diagnosis.

log_sys and recv_sys structures now use large memory allocations
for their large buffer.

Debug builds don't include the madvise syscall and as such will
include full core dumps.

A function, buf_madvise_do_dump, is added but never called. It
is there to be called from a debugger to re-enable the core
dumping of all of these pages if for some reason the entire
contents of these buffers are needed.

Idea thanks to Hartmut Holzgraefe

we have two the same 'if' clauses that check opt_bin_log argument
in mysqld.cc and both clauses go successively one after another.
Let's merge them into one