Relax the number-of-XA-engines check on recovery. Allow *more*
engines to be present than absolutely necessary, extra engines
cannot affect ACID guarantees of the recovery process.

As a bonus, 10.0->crash->10.1 upgrade won't complain about
wsrep being a new XA storge engine.

plugin_init() works like this:
1. init MyISAM
2. load plugins from mysql.plugin, if it's a MyISAM table
3. init all not initialized plugins
4. all done, if step 2 loaded mysql.plugin,
   otherwise:
5. load plugins from mysql.plugin
6. init all not initialized plugins

now, with --help --verbose, step 3 will not actually
initialize them, and if mysql.plugin is unreadable,
step 6 will try to initialize existing plugins again.
Fix: when skipping initialization because of --help,
change plugin status from PLUGIN_IS_UNINITIALIZED.

unit test for the IO_CACHE bug

While refreshing the IO_CACHE, do not update its parameters (read_pos,
read_end & pos_in_file) if there is nothing left to read.

Currently we support file block sizes 512K-4K.

Do not build optimised power crc32 on bigendian

Part I: Add diagnostics to page allocation if state is not correct
but do not assert if it is incorrect.

information from the page (note that page could be corrupt).

MDEV-9288: Use POWER8 accelerated crc32

Also removed surperflous stdio include.

Analysis: We have reserved ROW_MERGE_RESERVE_SIZE ( = 4) for
encryption key_version. When calculating is there more
space on sort buffer, this value needs to be substracted
from current available space.

10.1 man pages

MDEV-8923: port innodb_buffer_pool_dump_pct from MySQL

WL#6504 InnoDB buffer pool dump/load enchantments

This patch consists of two parts:

1. Dump only the hottest N% of the buffer pool(s)
2. Prevent hogging the server duing BP load

From MySQL - commit b409342c43ce2edb68807100a77001367c7e6b8e

Add testcases for innodb_buffer_pool_dump_pct.

Part of the code authored by Daniel Black.

 - Make accelerated checksum available to InnoDB and XtraDB.
 - Fall back to slice-by-eight if not available. The mode used is printed on startup.
 - Will only build on POWER systems at the moment until CMakeLists are modified
   to only add the crc32_power8/ files when building on POWER.

running MySQL-5.7 unittest/gunit/innodb/ut0crc32-t

Before:

1..2
Using software crc32 implementation, CPU is little-endian
ok 1
Using software crc32 implementation, CPU is little-endian
    normal CRC32: real    0.148006 sec
    normal CRC32: user    0.148000 sec
    normal CRC32: sys     0.000000 sec
big endian CRC32: real    0.144293 sec
big endian CRC32: user    0.144000 sec
big endian CRC32: sys     0.000000 sec
ok 2

After:

1..2
Using POWER8 crc32 implementation, CPU is little-endian
ok 1
Using POWER8 crc32 implementation, CPU is little-endian
    normal CRC32: real    0.008097 sec
    normal CRC32: user    0.008000 sec
    normal CRC32: sys     0.000000 sec
big endian CRC32: real    0.147043 sec
big endian CRC32: user    0.144000 sec
big endian CRC32: sys     0.000000 sec
ok 2

Author CRC32 ASM code: Anton Blanchard <anton@au.ibm.com>
ref: https://github.com/antonblanchard/crc32-vpmsumSigned-off-by: Daniel Black <daniel.black@au.ibm.com>

  modified:   storage/connect/fmdlex.c
  modified:   storage/connect/plgdbutl.cpp

  modified:   storage/connect/tabjson.cpp

- Added missning setting of table->rpl_write_set in record_gtid(), required by galera
- Removed output of WSREP_PATCH_VERSION from galera_defaults, as this can change over time
- Limit galera_many_tables_pk and galera_many_tables_nopk to 900, as
  on many systems the default open table limit is 1024

As 10.1 has systemd support, there is no longer need to set
_SYSTEMCTL_SKIP_REDIRECT/SYSTEMD_NO_WRAP.

Extended my_timer_cycles() to support s390.
Some compiler tunings for RHEL/SLES RPM packages on s390.

Always return NULL on error.
Adding also the file length.
  modified:   storage/connect/json.cpp
  modified:   storage/connect/jsonudf.cpp

- JSONCOL::WriteColumn Add types SHORT and BIGINT as accepted
  modified:   storage/connect/tabjson.cpp

- TDBJSN: Make this type use a separate storage for Json parsing
and retrieve this memory between each rows. This is necessary
to be able to handle big tables. See MDEV-9228.
  modified:   storage/connect/tabjson.cpp
  modified:   storage/connect/tabjson.h

Parsing memory, not added in CalcLen, is added in CheckMemory.
Adding also the file length.
  modified:   storage/connect/jsonudf.cpp

  modified:   storage/connect/filamzip.cpp

Avoid calling the wrong AddValue (Windows compiler error ???)
  modified:   storage/connect/json.h

Fix looping bug in JARRAY::AddValue for arrays having one value.
Fix potential crash in JVALUE::SetValue
  modified:   storage/connect/json.cpp

Many changes to fix bugs, enhance memory handling and modify Jpath.
In JSNX some functions have been re-written or added to handle new Jpath.
BMX was re-defined to avoid a different size between Windows an Linux.
Jbin memory was fixed to use the proper memory when adding values.
Default pretty value is now 0 instead of 2.
Filename is stored in BSON when IsJson == 2.
BSON size is added to memlen in CalcLen when applicable.
The order or parameter was switch in Json_Object_Grp.
File name argument must be a constant (temporary?)
Json_Set_Item now returns file name when applicable.
  modified:   storage/connect/jsonudf.cpp
  modified:   storage/connect/jsonudf.h

Include "mycat.h"
  modified:   storage/connect/mycat.cc

Udf_json test revisited and fixed for Linux
  modified:   storage/connect/mysql-test/connect/r/json_udf.result
  modified:   storage/connect/mysql-test/connect/t/json_udf.inc
  modified:   storage/connect/mysql-test/connect/t/json_udf.test
  modified:   storage/connect/mysql-test/connect/t/json_udf2.inc

myisam_recover is only an alias for myisam_recover_options.
Use the option name instead of the alias is more correct.
This also avoids an note about the use of an alias instead of the option
name on every server start.

by C runtime debug check.

Add testcases for innodb_buffer_pool_dump_pct

WL#6504 InnoDB buffer pool dump/load enchantments

This patch consists of two parts:

1. Dump only the hottest N% of the buffer pool(s)
2. Prevent hogging the server duing BP load

From MySQL - commit b409342c43ce2edb68807100a77001367c7e6b8e

no engines that don't support HA_READ_PREV)

Also, fixing compilation warnings in ctype-mb.ic (Windows).