and specifically the ack receiving functionality.
Semisync is turned to be static instead of plugin so its functions
are invoked at the same points as RUN_HOOKS.
The RUN_HOOKS and the observer interface remain to be removed by later
patch.
Todo:
React on killed status by repl_semisync_master.wait_after_sync(). Currently
Repl_semi_sync_master::commit_trx does not check the killed status.
There were few bugfixes found that are present in mysql and its unclear
whether/how they are covered. Those include:
Bug#15985893: GTID SKIPPED EVENTS ON MASTER CAUSE SEMI SYNC TIME-OUTS
Bug#17932935 CALLING IS_SEMI_SYNC_SLAVE() IN EACH FUNCTION CALL
HAS BAD PERFORMANCE
Bug#20574628: SEMI-SYNC REPLICATION PERFORMANCE DEGRADES WITH A HIGH NUMBER OF THREADS
RUN_HOOK() is only called if semisync is enabled
As the server can't disable the hooks if something is in progress, I added
a new variable, run_hooks_enabled, that is set the first time semi sync is
used. This means that RUN_HOOK will have no overhead, unless semi sync
master or slave has been enabled once.
Some of the changes was just to get rid of warnings for embedded server
Part of MDEV-13073 AliSQL Optimize performance of semisync
The idea it to use a dedicated lock detecting if there is new data in
the master's binary log instead of the overused LOCK_log.
Changes:
- Use dedicated COND variables for the relay and binary log signaling.
This was needed as we where the old 'update_cond' variable was used
with different mutex's, which could cause deadlocks.
- Relay log uses now COND_relay_log_updated and LOCK_log
- Binary log uses now COND_bin_log_updated and LOCK_binlog_end_pos
- Renamed signal_cnt to relay_signal_cnt (as we now have two signals)
- Added some missing error handling in MYSQL_BIN_LOG::new_file_impl()
- Reformatted some comments with old style
- Renamed m_key_LOCK_binlog_end_pos to key_LOCK_binlog_end_pos
- Changed 'signal_update()' to update_binlog_end_pos() which works for
both relay and binary log
Part of MDEV-13073 AliSQL Optimize performance of semisync
Did the following renames to match other similar variables
key_ss_mutex_LOCK_binlog_ > key_LOCK_bing
key_ss_cond_COND_binlog_send_ -> key_COND_binlog_send
COND_binlog_send_ -> COND_binlog_send
LOCK_binlog_ -> LOCK_binlog
debian/mariadb-server-10.2.install does not install semisync libs.
Feature Definition:-
This feature adds invisible column functionality to server.
There is 4 level of "invisibility":
1. Not invisible (NOT_INVISIBLE) — Normal columns created by the user
2. A little bit invisible (USER_DEFINED_INVISIBLE) — columns that the
user has marked invisible. They aren't shown in SELECT * and they
don't require values in INSERT table VALUE (...). Otherwise
they behave as normal columns.
3. More invisible (SYSTEM_INVISIBLE) — Can be queried explicitly,
otherwise invisible from everything. Think ROWID sytem column.
Because they're invisible from ALTER TABLE and from CREATE TABLE
they cannot be created or dropped, they're created by the system.
User cant not create a column name which is same as of
SYSTEM_INVISIBLE.
4. Very invisible (COMPLETELY_INVISIBLE) — as above, but cannot be
queried either. They can only show up in EXPLAIN EXTENDED (might
be possible for a very invisible indexed virtual column) but
otherwise they don't exist for the user.If user creates a columns
which has same name as of COMPLETELY_INVISIBLE then
COMPLETELY_INVISIBLE column is renamed again. So it is completely
invisible from user.
Invisible Index(HA_INVISIBLE_KEY):-
Creation of invisible columns require a new type of index which
will be only visible to system. User cant see/alter/create/delete
this index. If user creates a index which is same name as of
invisible index then it will be renamed.
Syntax Details:-
Only USER_DEFINED_INVISIBLE column can be created by user. This
can be created by adding INVISIBLE suffix after column definition.
Create table t1( a int invisible, b int);
Rules:-
There are some rules/restrictions related to use of invisible columns
1. All the columns in table cant be invisible.
Create table t1(a int invisible); \\error
Create table t1(a int invisible, b int invisble); \\error
2. If you want invisible column to be NOT NULL then you have to supply
Default value for the column.
Create table t1(a int, b int not null); \\error
3. If you create a view/create table with select * then this wont copy
invisible fields. So newly created view/table wont have any invisible
columns.
Create table t2 as select * from t1;//t2 wont have t1 invisible column
Create view v1 as select * from t1;//v1 wont have t1 invisible column
4. Invisibility wont be forwarded to next table in any case of create
table/view as select */(a,b,c) from table.
Create table t2 as select a,b,c from t1; // t2 will have t1 invisible
// column(b), but this wont be invisible in t2
Create view v1 as select a,b,c from t1; // v1 will have t1 invisible
// column(b), but this wont be invisible in v1
Implementation Details:-
Parsing:- INVISIBLE_SYM is added into vcol_attribute(so its like unique
suffix), It is also added into keyword_sp_not_data_type so that table
can have column with name invisible.
Implementation detail is given by each modified function/created function.
(Some function are left as they were self explanatory)
(m= Modified, n= Newly Created)
mysql_prepare_create_table(m):- Extra checks for invisible columns are
added. Also some DEBUG_EXECUTE_IF are also added for test cases.
mysql_prepare_alter_table(m):- Now this will drop all the
COMPLETELY_INVISIBLE column and HA_INVISIBLE_KEY index. Further
Modifications are made to stop drop/change/delete of SYSTEM_INVISIBLE
column.
build_frm_image(m):- Now this allows incorporating field_visibility
status into frm image. To remain compatible with old frms
field_visibility info will be only written when any of the field is
not NOT_INVISIBLE.
extra2_write_additional_field_properties(n):- This will write field
visibility info into buffer. We first write EXTRA2_FIELD_FLAGS into
buffer/frm , then each next char will have field_visibility for each
field.
init_from_binary_frm_image(m):- Now if we get EXTRA2_FIELD_FLAGS,
then we will read the next n(n= number of fields) chars and set the
field_visibility. We also increment
thd->status_var.feature_invisible_columns. One important thing to
note if we find out that key contains a field whose visibility is
> USER_DEFINED_INVISIBLE then , we declare this key as invisible
key.
sql_show.cc is changed accordingly to make show table, show keys
correct.
mysql_insert(m):- If we get to know that we are doing insert in
this way insert into t1 values(1,1); without explicitly specifying
columns, then we check for if we have invisible fields if yes then
we reset the whole record, Why ? Because first we want hidden columns
to get default/null value. Second thing auto_increment has property
no default and no null which voilates invisible key rule 2, And
because of this it was giving error. Reseting table->record[0]
eliminates this issue. More info put breakpoint on handler::write_row
and see auto_increment value.
fill_record(m):- we continue loop if we find invisible column because
this is already reseted/will get its value if it is default.
Test cases:- Since we can not directly add > USER_DEFINED_INVISIBLE
column then I have debug_dbug to create it in mysql_prepare_create_table.
Patch Credit:- Serg Golubchik
Instead of updating global counter, calculate Threads_running on the fly.
All threads having command != COM_SLEEP are included.
Behaviour changes:
Previously SHOW STATUS and SHOW GLOBAL STATUS returned the same values
representing global status. Now SHOW STATUS always returns 1 indicating that
current session has 1 thread running.
Previously only threads that were executing dispatch_command() or running events
were accounted by Threads_running. Now it is rough equivalent of
SELECT COUNT(*) FROM INFORMATION_SCHEMA.PROCESSLIST WHERE state!='Sleep'
first, and we do not not care whether client has received all data.
This is a TCP optimization to avoid TIME_WAIT in TCP connection teardown.
This patch would abort connection on timeout, which usually happens when
client reads a large result set, at slower pace then the server can
write.
The patch also cleans up socket timeout handling, so that Windows
is consistent with another platforms (using nonblocking socket IO
+ waiting in poll/select on single socket, rather than setsockopt).
This makes identifying timeouts easier.
Also removed the superficial shutdown() before closesocket() in a few
places where it was used, because it was never needed , and
reportedly breaks SO_LINGER on Windows.
LOCK_thd_data was used to protect both THD data and
ensure that the THD is not deleted while it was in use
This patch moves the THD delete protection to LOCK_thd_kill,
which already protects the THD for kill.
The benefits are:
- More well defined what LOCK_thd_data protects
- LOCK_thd_data usage is now much simpler and easier to verify
- Less chance of deadlocks in SHOW PROCESS LIST as there is less
chance of interactions between mutexes
- Remove not needed LOCK_thread_count from
thd_get_error_context_description()
- Fewer mutex taken for thd->awake()
Other things:
- Don't take mysys->var mutex in show processlist to check if thread
is kill marked
- thd->awake() now automatically takes the LOCK_thd_kill mutex
(Simplifies code)
- Apc uses LOCK_thd_kill instead of LOCK_thd_data
This is about adding more options to force slave retries
Two new variables has been added:
slave_transaction_retry_errors
- Tells the slave thread to retry transaction for replication when a
query event returns an error from the provided list. Deadlock and
elapsed lock wait timeout errors are automatically added to this list
slave-transaction-retry-interval
- Interval of the slave SQL thread will retry a transaction
in case it failed with a deadlock or elapsed lock wait
timeout or listed in slave_transaction_retry_errors
Other changes:
- Simplifed code for slave_skip_errors (to be aligned with
slave_transaction_retry_errors)
- Renamed print_slave_skip_errors() to make_slave_skip_errors_printable()
- Remove printing error from init_slave_skip_errors as my_bitmap_init()
will do that if needed.
- Generalize has_temporary_error()
- mysql_install_db now prints position to error file, if log-error is used
- Warning about compatibility now mentions MySQL 5.6 and 5.7
- Give warning if --show_compatibility_56 is used
This was done to get more information about where time is spent.
Now we can get proper timing for time spent in commit, rollback,
binlog write etc.
Following stages was added:
- Commit
- Commit_implicit
- Rollback
- Rollback implicit
- Binlog write
- Init for update
- This is used instead of "Init" for insert, update and delete.
- Staring cleanup
Following stages where changed:
- "Unlocking tables" stage reset stage to previous stage at end
- "binlog write" stage resets stage to previous stage at end
- "end" -> "end of update loop"
- "cleaning up" -> "Reset for next command"
- Added stage_searching_rows_for_update when searching for rows
to be deleted.
Other things:
- Renamed all stages to start with big letter (before there was no
consitency)
- Increased performance_schema_max_stage_classes from 150 to 160.
- Most of the test changes in performance schema comes from renaming of
stages.
- Removed duplicate output of variables and inital state in a lot of
performance schema tests.
This was done to make it easier to change a default value for a
performance variable without affecting all tests.
- Added start_server_variables.test to check configuration
- Removed some duplicate "closing tables" stages
- Updated position for "stage_init_update" and "stage_updating" for
delete, insert and update to be just before update loop (for more
exact timing).
- Don't set "Checking permissions" twice in a row.
- Remove stage_end stage from creating views (not done for create table
either).
- Updated default performance history size from 10 to 20 because of new
stages
- Ensure that ps_enabled is correct (to be used in a later patch)
The background is that one user had a lot of views and using some complex
queries on information schema temporary memory of more than 2G was used.
- Added new element 'total_alloc' to MEM_ROOT for easier debugging.
- Added MAX_MEMORY_USED to information_schema.processlist.
- Added new status variable "Memory_used_initial" that shows how much MariaDB
uses at startup. This gives the base value for "Memory_used".
- Reuse memory continuously for information schema queries instead of
only freeing memory at query end.
Other things
- Removed some not needed set_notnull() calls for not null columns.
'version' variables.
The warnings occur on Windows build, yet they are also are valid
on 32bit Unix.
Fix is to consistently use 64bit integer on all platforms.
- Fix win64 pointer truncation warnings
(usually coming from misusing 0x%lx and long cast in DBUG)
- Also fix printf-format warnings
Make the above mentioned warnings fatal.
- fix pthread_join on Windows to set return value.
- Added missing delete thd in bootstrap()
- Delete wrong 'delete thd' in start_wsrep_THD()
- Added missing 'delete thd' in case of SCHEDULER_ONE_THREAD_PER_CONNECTION
- Delete wrong dec_thread_running() in destroy_thd() as it caused thread_running
to be wrong.
- Moved reset_killed() to a normal function to make it easier to debug
- Added check of mutex in wsrep_aborting_thd... functions
full server recovery is performed .
We start "mysqld" with --bootstrap
and pass bootstrap script consisting of several FLUSH TABLES FOR export/
UNLOCK TABLES
Storage engine independent support for column compression.
TINYBLOB, BLOB, MEDIUMBLOB, LONGBLOB, TINYTEXT, TEXT, MEDIUMTEXT, LONGTEXT,
VARCHAR and VARBINARY columns can be compressed.
New COMPRESSED column attribute added:
COMPRESSED[=<compression_method>]
System variables added:
column_compression_threshold
column_compression_zlib_level
column_compression_zlib_strategy
column_compression_zlib_wrap
Status variables added:
Column_compressions
Column_decompressions
Limitations:
- the only supported method currently is zlib
- CSV storage engine stores data uncompressed on-disk even if COMPRESSED
attribute is present
- it is not possible to create indexes over compressed columns.
ATTRIBUTE_NORETURN is supported on all platforms (MSVS and GCC-like).
It declares that a function will not return; instead, the thread or
the whole process will terminate.
ATTRIBUTE_COLD is supported starting with GCC 4.3. It declares that
a function is supposed to be executed rarely. Rarely used error-handling
functions and functions that emit messages to the error log should be
tagged such.
For running the Galera tests, the variable my_disable_leak_check
was set to true in order to avoid assertions due to memory leaks
at shutdown.
Some adjustments due to MDEV-13625 (merge InnoDB tests from MySQL 5.6)
were performed. The most notable behaviour changes from 10.0 and 10.1
are the following:
* innodb.innodb-table-online: adjustments for the DROP COLUMN
behaviour change (MDEV-11114, MDEV-13613)
* innodb.innodb-index-online-fk: the removal of a (1,NULL) record
from the result; originally removed in MySQL 5.7 in the
Oracle Bug #16244691 fix
377774689b
* innodb.create-index-debug: disabled due to MDEV-13680
(the MySQL Bug #77497 fix was not merged from 5.6 to 5.7.10)
* innodb.innodb-alter-autoinc: MariaDB 10.2 behaves like MySQL 5.6/5.7,
while MariaDB 10.0 and 10.1 assign different values when
auto_increment_increment or auto_increment_offset are used.
Also MySQL 5.6/5.7 exhibit different behaviour between
LGORITHM=INPLACE and ALGORITHM=COPY, so something needs to be tested
and fixed in both MariaDB 10.0 and 10.2.
* innodb.innodb-wl5980-alter: disabled because it would trigger an
InnoDB assertion failure (MDEV-13668 may need additional effort in 10.2)
