Added ALTER ONLINE TABLE, which will give an error if the change can't be done 'instantly' (without a table copy)


mysql-test/r/alter_table_online.result:
  Test new feature
mysql-test/t/alter_table_online.test:
  Test new feature
sql/handler.cc:
  Added comment
sql/lex.h:
  Added ONLINE keyword
sql/mysql_priv.h:
  Added option to alter table to require online operation
sql/share/errmsg.txt:
  Added error message if ONLINE can't be done
sql/sql_lex.h:
  Added online option
sql/sql_parse.cc:
  Added online option to mysql_alter_table()
sql/sql_table.cc:
  Added test that gives error if table can't be done instantly when requsted to be online.
  Fixed wrong test if table includes a VARCHAR
  Fixed wrong (but unlikely) handling of error conditions in ALTER table
sql/sql_yacc.yy:
  Added ALTER ONLINE TABLE syntax
storage/maria/ha_maria.cc:
  Fixed bug where 'start_bulk_insert' used too small buffer if used with unknown number of rows

This makes it possible to do safe multi volume snapshots as long as one snapshots the volume with the transaction logs last.


include/mysql_com.h:
  Added REFRESH_CHECKPOINT
mysql-test/r/flush.result:
  Added test of new FLUSH TABLES syntax + calls to checkpoint_status handler calls
mysql-test/t/flush.test:
  Added test of new FLUSH TABLES syntax + calls to checkpoint_status handler calls
sql/handler.cc:
  Added code to call checkpoint_state for all handlertons that supports it
sql/handler.h:
  Added new checkpoint_state() handlerton call to temporarly disable checkpoints.
sql/lex.h:
  Added CHECKPOINT keyword
sql/sql_yacc.yy:
  Added support for FLUSH TABLES WITH READ LOCK AND DISABLE CHECKPOINT
storage/maria/ha_maria.cc:
  Added handlerton call to disable checkpoints.
storage/maria/ma_checkpoint.c:
  Don't do checkpoint if checkpoints are disabled.
storage/maria/ma_static.c:
  Added maria_checkpoint_disabled
storage/maria/maria_def.h:
  Added maria_checkpoint_disabled
storage/xtradb/handler/ha_innodb.cc:
  Added handlerton call to disable checkpoints.
storage/xtradb/include/log0log.h:
  Added option to log_checkpoint() to allow one to ignore not critical checkpoints during the time checkpoints are disabled.
storage/xtradb/log/log0log.c:
  Added code to allow one to disable checkpoints during a FLUSH TABLES ... DISABLE CHECKPOINT
  This was done by adding a new argument to log_checkpoint() which tells us when the checkpoint is called by srv_master_thread (which are safe to ignore)
storage/xtradb/srv/srv0srv.c:
  Tell log_checkpoint() that checkpoints from srv_master_thread() are safe to ignore (will just delay recovery time a bit).

Both these two bugs happened due to the following problem.
When a view column is referenced in the query an Item_direct_view_ref
object is created that is refers to the Item_field for the column.
All references to the same view column refer to the same Item_field.
Different references can belong to different AND/OR levels and,
as a result, can be included in different Item_equal object.
These Item_equal objects may include different constant objects.
If these constant objects are substituted for the Item_field created
for a view column we have a conflict situation when the second
substitution annuls the first substitution. This leads to
wrong result sets returned by the query. Bug #724942 demonstrates
such an erroneous behaviour.
Test case of the bug #717577 produces wrong result sets because best
equal fields of the multiple equalities built for different OR levels
of the WHERE condition differs. The subsitution for the best equal field
in the second OR branch overwrites the the substitution made for the
first branch.

To avoid such conflicts we have to substitute for the references
to the view columns rather than for the underlying field items.
To make such substitutions possible we have to include into
multiple equalities references to view columns rather than 
field items created for such columns.

This patch modifies the Item_equal class to include references
to view columns into multiple equality objects. It also performs
a clean up of the class methods and adds more comments. The methods
of the Item_direct_view_ref class that assist substitutions for
references to view columns has been also added by this patch.

In some cases the field max_part_no of the SEL_ARG structure
was not initialized. That triggered a Valgrind complain.

-fimplicit-termplates must be in CXXFLAGS not in handlersocket_la_CXXFLAGS.
otehrwise automake puts it in the command line too early to override
global -fno-implicit-templates

The problem was that connection con5, which is supposed to be the leader for
the third group, could if timing was bad end up as participant in the second
group, causing the test to fail.

Fixed by ensuring that group 2 is running before starting the transaction
for group 3.

LPBUG 756966 is solved.

 - MWL#116 Group commit
 - MWL#136 Enhancements for START TRANSACTION WITH CONSISTENT SNAPSHOT
 - MWL#47 Annotate_rows_log_event
 - MWL#163 innodb_release_locks_early
 - Percona patch enhancing row-based replication for tables with no primary key

- Let advance_sj_state() save the value of JOIN::cur_dups_producing_tables
  in POSITION::prefix_dups_producing_tables, and restore_sj_state() restore
  it. 

Also implement the InnoDB changes for group commit into innodb_plugin.

hold the latch across the 2-phase commit, and it is already released at
start of prepare (if not before).

Rename trx->active_trans to active_flag; since we changed the semantics of
the field, renaming should help prevent silent merge errors.

- Forgot to add .result file

Make EXPLAIN better at displaying MRR/BKA:
- Update all .result files
- Extra comments

- "Using MRR" is no longer shown with range access.
- Instead, both range and BKA accesses will show one of the following:
  = "Rowid-ordered scan"
  = "Key-ordered scan"
  = "Key-ordered Rowid-ordered scan"
depending on whether DS-MRR implementation will do scan keys in order, rowids in order,
or both.
- The patch also introduces a way for other storage engines/MRR implementations to
  pass information to EXPLAIN output about the properties of employed MRR scans.

sql/key.cc:
  Fixed compiler warnings about not initialized variables