For index merge union[or sort union], the estimates are not taken into account while calculating the selectivity of
a condition. So instead of showing the estimates of the index merge union[or sort union], it shows estimates equal to
all the records of the table.
The fix for the issue is to include the selectivity of index merge
union[or sort union] while calculating the selectivity of a condition.

branch.

--gdb now accepts an argument, it will be passed to gdb as a command.
multiple commands can be separated by a (non-standard and not escapable)
delimiter - semicolon (;).

Old usage with a bare --gdb continues to work too, of course.

Cherry-picked c47c0ca5 5441bbd3 339b9055

We should clear trailing zeroes in frac part. Otherwise
that tail is growing quickly and forces unnecessary truncating of
arguments.

row_drop_table_for_mysql(): Avoid accessing non-existing dictionary tables.

dict_create_or_check_foreign_constraint_tables(): Add debug instrumentation
for creating and dropping a table before the creation of any non-core
dictionary tables.

trx_purge_add_update_undo_to_history(): Adjust a debug assertion, so that
it will not fail due to the test instrumentation.

followup for e31e697f

Fix the test not to fail on Mac OS X
(lower_case_table_names=0 prevents mysqld from starting on case insensitive
filesystem)

commit 02d8c21380f
Author: Olivier Bertrand <bertrandop@gmail.com>
Date:   Sat Oct 6 16:27:13 2018 +0200

    - Fix truncating error messages on first unrecognized latin1 character
      modified:   storage/connect/ha_connect.cc

    - Fix MDEV-17343
      Reject multi-table UPDATE/DELETE commands that crash on some systems
      modified:   storage/connect/ha_connect.cc
      modified:   storage/connect/tabext.cpp

    - Try to fix failing tests (MariaDB version 10.0 only)
      modified:   storage/connect/mysql-test/connect/disabled.def

    - Typo
      modified:   storage/connect/global.h

commit f83caed8569
Author: Olivier Bertrand <bertrandop@gmail.com>
Date:   Tue Sep 25 15:49:26 2018 +0200

    - Try to fix failing tests (MariaDB version 10.0 only)
      modified:   storage/connect/mysql-test/connect/disabled.def
      modified:   storage/connect/mysql-test/connect/r/grant2.result
      modified:   storage/connect/mysql-test/connect/r/infoschema2-9739.result
      modified:   storage/connect/mysql-test/connect/r/mysql_exec.result

commit 9fd6f178846
Author: Olivier Bertrand <bertrandop@gmail.com>
Date:   Sun Sep 23 19:45:59 2018 +0200

    - Implement the CHECK TABLE statement and accept REPAIR and ANALYZE
      modified:   storage/connect/connect.cc
      modified:   storage/connect/ha_connect.cc
      modified:   storage/connect/ha_connect.h
      modified:   storage/connect/tabjdbc.cpp
      modified:   storage/connect/tabmysql.cpp
      modified:   storage/connect/tabodbc.cpp

    - MDEV-17212: Test if NumResultCols is implemented by the data source
      modified:   storage/connect/odbconn.cpp

    - Change error type in Optimize
      modified:   storage/connect/ha_connect.cc

    - Update version date
      modified:   storage/connect/ha_connect.cc

    - Record new result from odbc_postgresql.test
      modified:   storage/connect/mysql-test/connect/r/odbc_postgresql.result

commit d8cf51319e1
Author: Olivier Bertrand <bertrandop@gmail.com>
Date:   Wed Aug 8 12:18:52 2018 +0200

    - Comment out failing Cyrillic test in xml2.test
      modified:   storage/connect/mysql-test/connect/r/xml2.result
      modified:   storage/connect/mysql-test/connect/t/xml2.test

commit 9df49e21f9e
Author: Olivier Bertrand <bertrandop@gmail.com>
Date:   Tue Aug 7 15:01:06 2018 +0200

    - Fix MDEV-16672 Connect: Warnings with 10.0
      filamtxt.cpp: DOSFAM::RenameTempFile: Change sprintf to snprintf.
      filamvct.cpp: VECFAM::RenameTempFile: Change sprintf to snprintf.
      javaconn.cpp:
        Add JAVAConn::GetUTFString function.
        Use it instead of env->GetStringUTFChars.
        Fix wrong identation.
      javaconn.h: Add GetUTFString declaration.
      jdbconn.cpp:
        Use GetUTFString function instead of env->GetStringUTFChars.
      jmgoconn.cpp:
        Use GetUTFString function instead of env->GetStringUTFChars.
        Fix wrong identation.
      jsonudf.cpp: change 139 to BMX line 4631.
      tabjmg.cpp:
        Add ReleaseStringUTF.
        Fix wrong identation.
      tabpivot.cpp: Fix wrong identation.
      tabutil.cpp: TDBPRX::GetSubTable: Change sprintf to snprintf.
      modified:   storage/connect/filamtxt.cpp
      modified:   storage/connect/filamvct.cpp
      modified:   storage/connect/javaconn.cpp
      modified:   storage/connect/javaconn.h
      modified:   storage/connect/jdbconn.cpp
      modified:   storage/connect/jmgoconn.cpp
      modified:   storage/connect/jsonudf.cpp
      modified:   storage/connect/tabjmg.cpp
      modified:   storage/connect/tabpivot.cpp
      modified:   storage/connect/tabutil.cpp

    - Fix MDEV-16895 CONNECT engine's get_error_message can cause buffer
                     overflow and server crash with long queries
      ha_connect_cc: Update version.
        get_error_message: Remove charset conversion.
      modified:   storage/connect/ha_connect.cc

    - Fix a server crash on inserting bigint to a JDBC table
      JDBConn::SetUUID:
        Suppress check on ctyp that causes a server crash because ctyp
        can be negative and this triggers an DEBUG_ASSERT on return.
      modified:   storage/connect/jdbconn.cpp

    - Delete an assert(qrp) from JCATPARM *AllocCatInfo that is called with
      qrp=NULL from JDBConn::SetUUID. Also delete a clone of this function
      that was duplicated in javaconn.cpp.
      modified:   storage/connect/javaconn.cpp
      modified:   storage/connect/jdbconn.cpp

    - Update some disabled tests and results to avoid failure
      modified:   storage/connect/mysql-test/connect/r/jdbc.result
      modified:   storage/connect/mysql-test/connect/r/json_java_2.result
      modified:   storage/connect/mysql-test/connect/r/json_java_3.result
      modified:   storage/connect/mysql-test/connect/r/mongo_java_2.result
      modified:   storage/connect/mysql-test/connect/r/mongo_java_3.result
      modified:   storage/connect/mysql-test/connect/t/json_java_2.test
      modified:   storage/connect/mysql-test/connect/t/json_java_3.test
      modified:   storage/connect/mysql-test/connect/t/mongo_java_2.test
      modified:   storage/connect/mysql-test/connect/t/mongo_java_3.test

commit 415273eb193
Author: Olivier Bertrand <bertrandop@gmail.com>
Date:   Thu Jun 28 19:37:49 2018 +0200

    - Fix MDEV-16167 Cannot insert unsigned values into a VEC table
      modified:   storage/connect/filamvct.cpp
      modified:   storage/connect/tabvct.cpp

commit 9ffcb68a9f2
Author: Olivier Bertrand <bertrandop@gmail.com>
Date:   Mon May 7 22:43:43 2018 +0200

    - Fix MDEV-15735 CONNECT [filamtxt.cpp:429]: Suspicious condition
      modified:   storage/connect/filamtxt.cpp

    - Fix compiler warnings
      modified:   storage/connect/domdoc.cpp
      modified:   storage/connect/ha_connect.cc
      modified:   storage/connect/json.h
      modified:   storage/connect/jsonudf.cpp
      modified:   storage/connect/tabext.cpp
      modified:   storage/connect/tabjson.cpp
      modified:   storage/connect/tabjson.h

    - Miscelleanous from 10.3
      modified:   storage/connect/ha_connect.cc
      modified:   storage/connect/mycat.cc
      modified:   storage/connect/user_connect.cc

System libxml2 uses system zlib, it might conflicts with the bundled.

In particular, on centos5 old system zlib conflicts with the newer
(after c5427172) bundled zlib which causes CONNECT to crash
on xml tests.

Also, add a test for a bug that does not seem to affect MariaDB.

MDEV-17532 Performance_schema reports wrong directory for the temporary files of ALTER TABLE…ALGORITHM=INPLACE

row_merge_file_create_low(): Pass the directory of the temporary file
to the PSI_FILE_CALL.

In RENAME TABLE, when an error occurs while renaming FOREIGN KEY
constraint, that error would be overwritten when renaming the
InnoDB internal tables related to FULLTEXT INDEX.

row_rename_table_for_mysql(): Do not attempt to rename the internal
tables if an error already occurred.

This problem was originally reported as Oracle Bug#27545888.

This reverts commit ebaacf07.

Pushed by mistake.
Broke tokudb on trusty-amd64.

test case

This reverts commit dc3a20b1.

It requires GET_BIT in include/my_getopt.h, which is available
only in 10.3+

mysql_upgrade used to convert all columns of mysql.db to
utf8_general_ci and then back to utf8_bin. In two separate ALTER's.

This failed if UNIQUE indexes in mysql.db contained entries
that differ only in the letter case.

             in thr_lock / has_old_lock upon FLUSH TABLES

Explicit partition access of partitioned MEMORY table under LOCK TABLES
may cause subsequent statements to crash the server, deadlock, trigger
valgrind warnings or ASAN errors. Freed memory was being used due to
incorrect cleanup.

At least MyISAM and InnoDB don't seem to be affected, since their
THR_LOCK structures don't survive FLUSH TABLES. MEMORY keeps table shared
data (including THR_LOCK) even if there're no open instances.

There's partition_info::lock_partitions bitmap, which holds bits of
partitions allowed to be accessed after pruning. This bitmap is
updated for each individual statement.

This bitmap was abused in ha_partition::store_lock() such that when we
need to unlock a table, locked by LOCK TABLES, only locks for partitions
that were accessed by previous statement were released.

Eventually FLUSH TABLES frees THR_LOCK_DATA objects, which are still
linked into THR_LOCK lists. When such THR_LOCK gets reused we end up with
freed memory access.

Fixed by using ha_partition::m_locked_partitions bitmap similarly to
ha_partition::external_lock().

 consistently) on Replication Slave

lower_case_table_names  0 -> 1 replication works, it's safe as long as
 mixed case names mapping to the lower case ones is one-to-one

MDEV-17257 Server crashes in Item::field_type_for_temporal_comparison or in get_datetime_value on SELECT with YEAR field and IN