==== Description ====
Flashback can rollback the instances/databases/tables to an old snapshot.
It's implement on Server-Level by full image format binary logs (--binlog-row-image=FULL), so it supports all engines.
Currently, it’s a feature inside mysqlbinlog tool (with --flashback arguments).
Because the flashback binlog events will store in the memory, you should check if there is enough memory in your machine.
==== New Arguments to mysqlbinlog ====
--flashback (-B)
It will let mysqlbinlog to work on FLASHBACK mode.
==== New Arguments to mysqld ====
--flashback
Setup the server to use flashback. This enables binary log in row mode
and will enable extra logging for DDL's needed by flashback feature
==== Example ====
I have a table "t" in database "test", we can compare the output with "--flashback" and without.
#client/mysqlbinlog /data/mysqldata_10.0/binlog/mysql-bin.000001 -vv -d test -T t --start-datetime="2013-03-27 14:54:00" > /tmp/1.sql
#client/mysqlbinlog /data/mysqldata_10.0/binlog/mysql-bin.000001 -vv -d test -T t --start-datetime="2013-03-27 14:54:00" -B > /tmp/2.sql
Then, importing the output flashback file (/tmp/2.log), it can flashback your database/table to the special time (--start-datetime).
And if you know the exact postion, "--start-postion" is also works, mysqlbinlog will output the flashback logs that can flashback to "--start-postion" position.
==== Implement ====
1. As we know, if binlog_format is ROW (binlog-row-image=FULL in 10.1 and later), all columns value are store in the row event, so we can get the data before mis-operation.
2. Just do following things:
2.1 Change Event Type, INSERT->DELETE, DELETE->INSERT.
For example:
INSERT INTO t VALUES (...) ---> DELETE FROM t WHERE ...
DELETE FROM t ... ---> INSERT INTO t VALUES (...)
2.2 For Update_Event, swapping the SET part and WHERE part.
For example:
UPDATE t SET cols1 = vals1 WHERE cols2 = vals2
--->
UPDATE t SET cols2 = vals2 WHERE cols1 = vals1
2.3 For Multi-Rows Event, reverse the rows sequence, from the last row to the first row.
For example:
DELETE FROM t WHERE id=1; DELETE FROM t WHERE id=2; ...; DELETE FROM t WHERE id=n;
--->
DELETE FROM t WHERE id=n; ...; DELETE FROM t WHERE id=2; DELETE FROM t WHERE id=1;
2.4 Output those events from the last one to the first one which mis-operation happened.
For example:
Gtid_list_log_event::do_apply_event() did not free_root(thd->mem_root).
It can allocate on this in record_gtid(), and in some scenarios there is
nothing else that does free_root(), leading to temporary memory leak until
stop of SQL thread. One scenario is in circular replication with only one
master active. The active master receives only its own events on the slave,
all of which are ignored. But whenever the SQL thread catches up with the IO
thread, a Gtid_list_log_event is applied, leading to the leak.
- MDEV-11621 rpl.rpl_gtid_stop_start fails sporadically in buildbot
- MDEV-11620 rpl.rpl_upgrade_master_info fails sporadically in buildbot
The issue above was probably that the build machine was overworked and the
shutdown took longer than 30 resp 10 seconds, which caused MyISAM tables
to be marked as crashed.
Fixed by flushing myisam tables before doing a forced shutdown/kill.
I also increased timeout for forced shutdown from 10 seconds to 60 seconds
to fix other possible issues on slow machines.
Fixed also some compiler warnings
This has no functional changes, but it helps avoid merge problems from 10.0
to 10.1. In 10.0, code that checks for parallel replication uses
opt_slave_parallel_threads > 0, but this check needs to be
mi->using_parallel() in 10.1. By using the same check in 10.0 (with
unchanged semantics), merge problems to 10.1 are avoided.
Minor review comments/changes:
- A bunch of style-fixes.
- Change macros to static inline functions.
- Update check_event_type() with compressed event types.
- Small .result file update.
Add some event types for the compressed event, there are:
QUERY_COMPRESSED_EVENT,
WRITE_ROWS_COMPRESSED_EVENT_V1,
UPDATE_ROWS_COMPRESSED_EVENT_V1,
DELETE_POWS_COMPRESSED_EVENT_V1,
WRITE_ROWS_COMPRESSED_EVENT,
UPDATE_ROWS_COMPRESSED_EVENT,
DELETE_POWS_COMPRESSED_EVENT.
These events inheritance the uncompressed editor events. One of their constructor functions and write
function have been overridden for uncompressing and compressing. Anything but this is totally the same.
On slave, The IO thread will uncompress and convert them When it receiving the events from the master.
So the SQL and worker threads can be stay unchanged.
Now we use zlib as compress algorithm. It maybe support other algorithm in the future.
Merge feature into 10.2 from feature branch.
Delayed replication adds an option
CHANGE MASTER TO master_delay=<seconds>
Replication will then delay applying events with that many
seconds. This creates a replication slave that reflects the state of
the master some time in the past.
Feature is ported from MySQL source tree.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
The original MySQL patch left some refactoring todo's, possibly
because of known conflicts with other parallel development (like
info-repository feature perhaps).
This patch fixes those todos/refactorings.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
Initial merge of delayed replication from MySQL git.
The code from the initial push into MySQL is merged, and the
associated test case passes. A number of tasks are still pending:
1. Check full test suite run for any regressions or .result file updates.
2. Extend the feature to also work for parallel replication.
3. There are some todo-comments about future refactoring left from
MySQL, these should be located and merged on top.
4. There are some later related MySQL commits, these should be checked
and merged. These include:
e134b9362ba0b750d6ac1b444780019622d14aa5
b38f0f7857c073edfcc0a64675b7f7ede04be00f
fd2b210383358fe7697f201e19ac9779879ba72a
afc397376ec50e96b2918ee64e48baf4dda0d37d
5. The testcase from MySQL relies heavily on sleep and timing for
testing, and seems likely to sporadically fail on heavily loaded test
servers in buildbot or distro build farms.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
MDEV-10134 Add full support for DEFAULT
- Added support for using tables with MySQL 5.7 virtual fields,
including MySQL 5.7 syntax
- Better error messages also for old cases
- CREATE ... SELECT now also updates timestamp columns
- Blob can now have default values
- Added new system variable "check_constraint_checks", to turn of
CHECK constraint checking if needed.
- Removed some engine independent tests in suite vcol to only test myisam
- Moved some tests from 'include' to 't'. Should some day be done for all tests.
- FRM version increased to 11 if one uses virtual fields or constraints
- Changed to use a bitmap to check if a field has got a value, instead of
setting HAS_EXPLICIT_VALUE bit in field flags
- Expressions can now be up to 65K in total
- Ensure we are not refering to uninitialized fields when handling virtual fields or defaults
- Changed check_vcol_func_processor() to return a bitmap of used types
- Had to change some functions that calculated cached value in fix_fields to do
this in val() or getdate() instead.
- store_now_in_TIME() now takes a THD argument
- fill_record() now updates default values
- Add a lookahead for NOT NULL, to be able to handle DEFAULT 1+1 NOT NULL
- Automatically generate a name for constraints that doesn't have a name
- Added support for ALTER TABLE DROP CONSTRAINT
- Ensure that partition functions register virtual fields used. This fixes
some bugs when using virtual fields in a partitioning function
Fix the replication failure caused by incorect initialization of
THD::invoker_host && THD::invoker_user.
Breakdown of the failure is this:
Query_log_event::host and Query_log_event::user can have their
LEX_STRING's set to length 0, but the actual str member points to
garbage. Code afterwards copies Query_log_event::host and user to
THD::invoker_host and THD::invoker_user.
Calling code for these members expects both members to be initialized.
Eg. the str member be a NULL terminated string and length have
appropriate size.
mysqld maintains a list of TABLE objects for all temporary
tables created within a session in THD. Here each table is
represented by a TABLE object.
A query referencing a particular temporary table for more
than once, however, failed with ER_CANT_REOPEN_TABLE error
because a TABLE_SHARE was allocate together with the TABLE,
so temporary tables always had only one TABLE per TABLE_SHARE.
This patch lift this restriction by separating TABLE and
TABLE_SHARE objects and storing TABLE_SHAREs for temporary
tables in a list in THD, and TABLEs in a list within their
respective TABLE_SHAREs.
This is done by splitting variables.errmsg and locale.errmsg to
variables.errmsg_extra and locale.errmsg_extra
The ER() macros in unireg.h now looks more complex than before, but this
isn't critical as most usage of them are with constants and the compiler
will remove most of the test code.
LOG-SLOW-SLAVE-STATEMENTS NOT DISPLAYED.
These parameters were moved from the command line options to
the system variables section. Treatment of the
opt_log_slow_slave_statements changed to let the
dynamic change of the variable.
delete deferred events after they're executed
(otherwise they can be executed again for a sub-statement)
See also
commit 0e78d1d
Author: Venkatesh Duggirala <venkatesh.duggirala@oracle.com>
Date: Wed Mar 20 11:20:47 2013 +0530
BUG#15850951-DUPLICATE ERROR IN REPLICATION WITH SLAVE
TRIGGERS AND AUTO INCREMENT
REPLICATION
Problem: In RBR mode, merge table updates are not successfully applied on a cascading
replication.
Analysis & Fix: Every type of row event is preceded by one or more table_map_log_events
that gives the information about all the tables that are involved in the row
event. Server maintains the list in RPL_TABLE_LIST and it goes through all the
tables and checks for the compatibility between master and slave. Before
checking for the compatibility, it calls 'open_tables()' which takes the list
of all tables that needs to be locked and opened. In RBR, because of the
Table_map_log_event , we already have all the tables including base tables in
the list. But the open_tables() which is generic call takes care of appending
base tables if the list contains merge tables. There is an assumption in the
current replication layer logic that these tables (TABLE_LIST type objects) are always
added in the end of the list. Replication layer maintains the count of
tables(tables_to_lock_count) that needs to be verified for compatibility check
and runs through only those many tables from the list and rest of the objects
in linked list can be skipped. But this assumption is wrong.
open_tables()->..->add_children_to_list() adds base tables to the list immediately
after seeing the merge table in the list.
For eg: If the list passed to open_tables() is t1->t2->t3 where t3 is merge
table (and t1 and t2 are base tables), it adds t1'->t2' to the list after t3.
New table list looks like t1->t2->t3->t1'->t2'. It looks like it added at the
end of the list but that is not correct. If the list passed to open_tables()
is t3->t1->t2 where t3 is merge table (and t1 and t2 are base tables), the new
prepared list will be t3->t1'->t2'->t1->t2. Where t1' and t2' are of
TABLE_LIST objects which were added by add_children_to_list() call and replication
layer should not look into them. Here tables_to_lock_count will not help as the
objects are added in between the list.
Fix: After investigating add_children_list() logic (which is called from open_tables()),
there is no flag/logic in it to skip adding the children to the list even if the
children are already included in the table list. Hence to fix the issue, a
logic should be added in the replication layer to skip children in the list by
checking whether 'parent_l' is non-null or not. If it is children, we will skip 'compatibility'
check for that table.
Also this patch is not removing 'tables_to_lock_count' logic for the performance issues
if there are any children at the end of the list, those can be easily skipped directly by
stopping the loop with tables_to_lock_count check.
