Some queries with the "SELECT ... FROM DUAL" nested subqueries
failed with an assertion on debug builds.
Non-debug builds were not affected.
There were a few different issues with similar assertion
failures on different queries:
1. The first problem was related to the incomplete propagation
of the "non-constant" item status from underlying subquery
items to the outer item tree: in some cases non-constants were
interpreted as constants and evaluated at the preparation stage
(val_int() calls withing fix_fields() etc).
Thus, the default implementation of Item_ref::const_item() from
the Item parent class didn't take into account the "const_item"
status of the referenced item tree -- it used the insufficient
"used_tables() == 0" check instead. This worked in most cases
since our "non-constant" functions like RAND() and SLEEP() set
the RAND_TABLE_BIT in the used table map, so they aren't
non-constant from Item_ref's "point of view". However, the
"SELECT ... FROM DUAL" subquery may have an empty map of used
tables, but at the same time subqueries are never "constant" at
the context analysis stage (preparation, view creation etc).
So, the non-contantness of such subqueries was missed.
Fix: the Item_ref::const_item() function has been overloaded to
take into account both (*ref)->const_item() status and tricky
Item_ref::used_tables() return values, since the only
(*ref)->const_item() call is not enough there.
2. In some cases instead of the const_item() call we check a
value of the Item::with_subselect field to recognize items
with nested subqueries. However, the Item_ref class didn't
propagate this value from the referenced item tree.
Fix: Item::has_subquery() and Item_ref::has_subquery()
functions have been backported from 5.6. All direct
references to the with_subselect fields of nested items have
been with the has_subquery() function call.
3. The Item_func_regex class didn't propagate with_subselect
as well, since it overloads the Item_func::fix_fields()
function with insufficient fix_fields() implementation.
Fix: the Item_func_regex::fix_fields() function has been
modified to gather "constant" statuses from inner items.
4. The Item_func_isnull::update_used_tables() function has
a special branch for the underlying item where the maybe_null
value is false: in this case it marks the Item_func_isnull
as a "const_item" and sets the cached_value to false.
However, the Item_func_isnull::val_int() was not in sync with
update_used_tables(): it didn't take into account neither
const_item_cache nor cached_value for the case of
"args[0]->maybe_null == false optimization".
As far as such an Item_func_isnull has "const_item() == true",
it's ok to call Item_func_isnull::val_int() etc from outer
items on preparation stage. In this case the server tried to
call Item_func_isnull::args[0]->isnull(), and if the args[0]
item contained a nested not-nullable subquery, it failed
with an assertion.
Fix: take the value of Item_func_isnull::const_item_cache into
account in the val_int() function.
5. The auxiliary Item_is_not_null_test class has a similar
optimization in the update_used_tables() function as the
Item_func_isnull class has, and the same issue in the val_int()
function.
In addition to that the Item_is_not_null_test::update_used_tables()
doesn't update the const_item_cache value, so the "maybe_null"
optimization is useless there. Thus, we missed some optimizations
of cases like these (before and after the fix):
< <is_not_null_test>(a),
---
> <cache>(<is_not_null_test>(a)),
or
< having (<is_not_null_test>(a) and <is_not_null_test>(a))
---
> having 1
etc.
Fix: update Item_is_not_null_test::const_item_cache in
update_used_tables() and take in into account in val_int().
Some queries with the "SELECT ... FROM DUAL" nested subqueries
failed with an assertion on debug builds.
Non-debug builds were not affected.
There were a few different issues with similar assertion
failures on different queries:
1. The first problem was related to the incomplete propagation
of the "non-constant" item status from underlying subquery
items to the outer item tree: in some cases non-constants were
interpreted as constants and evaluated at the preparation stage
(val_int() calls withing fix_fields() etc).
Thus, the default implementation of Item_ref::const_item() from
the Item parent class didn't take into account the "const_item"
status of the referenced item tree -- it used the insufficient
"used_tables() == 0" check instead. This worked in most cases
since our "non-constant" functions like RAND() and SLEEP() set
the RAND_TABLE_BIT in the used table map, so they aren't
non-constant from Item_ref's "point of view". However, the
"SELECT ... FROM DUAL" subquery may have an empty map of used
tables, but at the same time subqueries are never "constant" at
the context analysis stage (preparation, view creation etc).
So, the non-contantness of such subqueries was missed.
Fix: the Item_ref::const_item() function has been overloaded to
take into account both (*ref)->const_item() status and tricky
Item_ref::used_tables() return values, since the only
(*ref)->const_item() call is not enough there.
2. In some cases instead of the const_item() call we check a
value of the Item::with_subselect field to recognize items
with nested subqueries. However, the Item_ref class didn't
propagate this value from the referenced item tree.
Fix: Item::has_subquery() and Item_ref::has_subquery()
functions have been backported from 5.6. All direct
references to the with_subselect fields of nested items have
been with the has_subquery() function call.
3. The Item_func_regex class didn't propagate with_subselect
as well, since it overloads the Item_func::fix_fields()
function with insufficient fix_fields() implementation.
Fix: the Item_func_regex::fix_fields() function has been
modified to gather "constant" statuses from inner items.
4. The Item_func_isnull::update_used_tables() function has
a special branch for the underlying item where the maybe_null
value is false: in this case it marks the Item_func_isnull
as a "const_item" and sets the cached_value to false.
However, the Item_func_isnull::val_int() was not in sync with
update_used_tables(): it didn't take into account neither
const_item_cache nor cached_value for the case of
"args[0]->maybe_null == false optimization".
As far as such an Item_func_isnull has "const_item() == true",
it's ok to call Item_func_isnull::val_int() etc from outer
items on preparation stage. In this case the server tried to
call Item_func_isnull::args[0]->isnull(), and if the args[0]
item contained a nested not-nullable subquery, it failed
with an assertion.
Fix: take the value of Item_func_isnull::const_item_cache into
account in the val_int() function.
5. The auxiliary Item_is_not_null_test class has a similar
optimization in the update_used_tables() function as the
Item_func_isnull class has, and the same issue in the val_int()
function.
In addition to that the Item_is_not_null_test::update_used_tables()
doesn't update the const_item_cache value, so the "maybe_null"
optimization is useless there. Thus, we missed some optimizations
of cases like these (before and after the fix):
< <is_not_null_test>(a),
---
> <cache>(<is_not_null_test>(a)),
or
< having (<is_not_null_test>(a) and <is_not_null_test>(a))
---
> having 1
etc.
Fix: update Item_is_not_null_test::const_item_cache in
update_used_tables() and take in into account in val_int().
Analysis
The reason for the less efficient plan was result of a prior design decision -
to limit the eveluation of constant expressions during optimization to only
non-expensive ones. With this approach all stored procedures were considered
expensive, and were not evaluated during optimization. As a result, SPs didn't
participate in range optimization, which resulted in a plan with table scan
rather than index range scan.
Solution
Instead of considering all SPs expensive, consider expensive only those SPs
that are non-deterministic. If an SP is deterministic, the optimizer will
checj if it is constant, and may eventually evaluate it during optimization.
from a MERGE view.
The problem was in the lost ability to be null for the table of a left join if it
is a view/derived table.
It hapenned because setup_table_map(), was called earlier then we merged
the view or derived.
Fixed by propagating new maybe_null flag during Item::update_used_tables().
Change in join_outer.test and join_outer_jcl6.test appeared because
IS NULL reported no used tables (i.e. constant) for argument which could not be
NULL and new maybe_null flag was propagated for IS NULL argument (Item_field)
because table the Item_field belonged to changed its maybe_null status.
VARIABLES
Analysis:
-------------
After executing the query, new value of the user defined
variables are set in the function "select_dumpvar::send_data".
"select_dumpvar::send_data" first calls function
"Item_func_set_user_var::save_item_result()". This function
checks the nullness of the Item_field passed as parameter
to it and saves it. The nullness of item is stored with
arg[0]'s null_value flag. Then "select_dumpvar::send_data" calls
"Item_func_set_user_var::update()" which notices null
result that was saved and calls "Item_func_set_user_var::
update_hash". But here null_value is not set and args[0]
is different from that given to function "Item_func_set_user_var::
set_item_result()". This causes "Item_func_set_user_var::
update_hash" function to believe that its getting non-null value.
"user_var_entry::length" set to 0 and hence "user_var_entry::value"
is made to point to extra_area allocated in "user_var_entry".
And "Item_func_set_user_var::update_hash" tries to write
at memory beyond extra_area for result type DECIMAL. Because of
this invalid write issue is reported by Valgrind.
Before this bug was introduced, we avoided this problem by
creating "Item_func_set_user_var" object with the same
Item_field as arg[0] and as parameter to
Item_func_set_user_var::save_item_result(). But now
they are refering to different args[0]. Because of this
null_value flag set in parameter Item_field in function
"Item_func_set_user_var::save_item_result()" is not
reflected in "Item_func_set_user_var" object.
Fix:
------------
This issue is reported on versions 5.5.24. Issue does not exists
in 5.5.23, 5.1, 5.6 and trunk.
This issue was introduced by
revid:georgi.kodinov@oracle.com-20120309130449-82e3bs5v3et1x0ef (fix for
bug #12408412), which was pushed into 5.5 and later releases. This patch
has later been reversed in 5.6 and trunk by
revid:norvald.ryeng@oracle.com-20121010135242-xj34gg73h04hrmyh (fix for
bug #14664077). Backported this patch in 5.5 also to fix this issue.
sql/item_func.cc:
here unsigned value is converted to signed value.
sql/item_func.h:
last_insert_id() gives an auto_incremented value which can be
positive only,so defined it as a unsigned longlong sets the
unsigned_flag to 1.
VARIABLES
Analysis:
-------------
After executing the query, new value of the user defined
variables are set in the function "select_dumpvar::send_data".
"select_dumpvar::send_data" first calls function
"Item_func_set_user_var::save_item_result()". This function
checks the nullness of the Item_field passed as parameter
to it and saves it. The nullness of item is stored with
arg[0]'s null_value flag. Then "select_dumpvar::send_data" calls
"Item_func_set_user_var::update()" which notices null
result that was saved and calls "Item_func_set_user_var::
update_hash". But here null_value is not set and args[0]
is different from that given to function "Item_func_set_user_var::
set_item_result()". This causes "Item_func_set_user_var::
update_hash" function to believe that its getting non-null value.
"user_var_entry::length" set to 0 and hence "user_var_entry::value"
is made to point to extra_area allocated in "user_var_entry".
And "Item_func_set_user_var::update_hash" tries to write
at memory beyond extra_area for result type DECIMAL. Because of
this invalid write issue is reported by Valgrind.
Before this bug was introduced, we avoided this problem by
creating "Item_func_set_user_var" object with the same
Item_field as arg[0] and as parameter to
Item_func_set_user_var::save_item_result(). But now
they are refering to different args[0]. Because of this
null_value flag set in parameter Item_field in function
"Item_func_set_user_var::save_item_result()" is not
reflected in "Item_func_set_user_var" object.
Fix:
------------
This issue is reported on versions 5.5.24. Issue does not exists
in 5.5.23, 5.1, 5.6 and trunk.
This issue was introduced by
revid:georgi.kodinov@oracle.com-20120309130449-82e3bs5v3et1x0ef (fix for
bug #12408412), which was pushed into 5.5 and later releases. This patch
has later been reversed in 5.6 and trunk by
revid:norvald.ryeng@oracle.com-20121010135242-xj34gg73h04hrmyh (fix for
bug #14664077). Backported this patch in 5.5 also to fix this issue.
MDEV-26: Global transaction id, partial commit
Change server_id to be a session variable.
User with SUPER can set it to binlog with different server_id.
Implement backward-compatible ::server_id mirror for plugins.
Problem:-
using last_insert_id() on an auto_incremented bigint unsigned does
not work for values which are greater than max-bigint-signed.
Analysis:-
last_insert_id() returns the first auto_incremented value for a column
and an auto_incremented value can have only positive values.
In our code, when we are initializing a last_insert_id object, we are
taking it as a signed BIGINT, So when the auto_incremented value reaches
greater than max signed bigint, last_insert_id gives negative result.
Solution:
When we are fetching the value from last_insert_id, We are setting the
unsigned_flag, so that it take only unsigned BIGINT value.
sql/item_func.cc:
here unsigned value is converted to signed value.
sql/item_func.h:
last_insert_id() gives an auto_incremented value which can be
positive only,so defined it as a unsigned longlong sets the
unsigned_flag to 1.
Problem:-
using last_insert_id() on an auto_incremented bigint unsigned does
not work for values which are greater than max-bigint-signed.
Analysis:-
last_insert_id() returns the first auto_incremented value for a column
and an auto_incremented value can have only positive values.
In our code, when we are initializing a last_insert_id object, we are
taking it as a signed BIGINT, So when the auto_incremented value reaches
greater than max signed bigint, last_insert_id gives negative result.
Solution:
When we are fetching the value from last_insert_id, We are setting the
unsigned_flag, so that it take only unsigned BIGINT value.
Problem:-
using last_insert_id() on an auto_incremented bigint unsigned does
not work for values which are greater than max-bigint-signed.
Analysis:-
last_insert_id() returns the first auto_incremented value for a column
and an auto_incremented value can have only positive values.
In our code, when we are initializing a last_insert_id object, we are
taking it as a signed BIGINT, So when the auto_incremented value reaches
greater than max signed bigint, last_insert_id gives negative result.
Solution:
When we are fetching the value from last_insert_id, We are setting the
unsigned_flag, so that it take only unsigned BIGINT value.
sql/item_func.cc:
here unsigned value is converted to signed value.
sql/item_func.h:
last_insert_id() gives an auto_incremented value which can be
positive only,so defined it as a unsigned longlong sets the
unsigned_flag to 1.
Problem:-
using last_insert_id() on an auto_incremented bigint unsigned does
not work for values which are greater than max-bigint-signed.
Analysis:-
last_insert_id() returns the first auto_incremented value for a column
and an auto_incremented value can have only positive values.
In our code, when we are initializing a last_insert_id object, we are
taking it as a signed BIGINT, So when the auto_incremented value reaches
greater than max signed bigint, last_insert_id gives negative result.
Solution:
When we are fetching the value from last_insert_id, We are setting the
unsigned_flag, so that it take only unsigned BIGINT value.
Documentation of the feature can be found at: http://kb.askmonty.org/en/multi-source-replication/
This code is based on code from Taobao, developed by Plinux
BUILD/SETUP.sh:
Added -Wno-invalid-offsetof to get rid of warning of offsetof() on C++ class (safe in the contex we use it)
client/mysqltest.cc:
Added support for error names starting with 'W'
Added connection_name support to --sync_with_master
cmake/maintainer.cmake:
Added -Wno-invalid-offsetof to get rid of warning of offsetof() on C++ class (safe in the contex we use it)
mysql-test/r/mysqltest.result:
Updated results
mysql-test/r/parser.result:
Updated results
mysql-test/suite/multi_source/my.cnf:
Setup of multi-master tests
mysql-test/suite/multi_source/simple.result:
Simple basic test of multi-source functionality
mysql-test/suite/multi_source/simple.test:
Simple basic test of multi-source functionality
mysql-test/suite/multi_source/syntax.result:
Test of multi-source syntax
mysql-test/suite/multi_source/syntax.test:
Test of multi-source syntax
mysql-test/suite/rpl/r/rpl_rotate_logs.result:
Updated results because of new error messages
mysql-test/t/parser.test:
Updated test as master_pos_wait() now takes more arguments than before
sql/event_scheduler.cc:
No reason to initialize slave_thread (it's guaranteed to be zero here)
sql/item_create.cc:
Added connection_name argument to master_pos_wait()
Simplified code
sql/item_func.cc:
Added connection_name argument to master_pos_wait()
sql/item_func.h:
Added connection_name argument to master_pos_wait()
sql/log.cc:
Added tag "Master 'connection_name'" to slave errors that has a connection name.
sql/mysqld.cc:
Added variable mysqld_server_initialized so that other functions can test if server is fully initialized.
Free all slave data in one place (fewer ifdef's)
Removed not needed call to close_active_mi()
Initialize slaves() later in startup to ensure that everthing is really initialized when slaves start.
Made status variable slave_running multi-source safe
sql/mysqld.h:
Added mysqld_server_initialized
sql/rpl_mi.cc:
Store connection name and cmp_connection_name (only used for show full slave status) in Master_info
Added code for Master_info_index, which handles storage of multi-master information
Don't write the empty "" connection_name to multi-master.info file. This is handled by the original code.
sql/rpl_mi.h:
Added connection_name and Master_info_index
sql/rpl_rli.cc:
Added connection_name to relay log files.
sql/rpl_rli.h:
Fixed type of slave_skip_counter as we now access it directly in sys_vars.cc, so it must be uint
sql/share/errmsg-utf8.txt:
Added new error messages needed for multi-source
Added multi-source name to error ER_MASTER_INFO and WARN_NO_MASTER_INFO
sql/slave.cc:
Moved things a bit around to make it easier to handle error conditions.
Create a global master_info_index and add the "" connection to it
Ensure that new Master_info doesn't fail.
Don't call terminate_slave_threads(active_mi..) on end_slave() as this is now done automaticly when deleting master_info_index.
Delete not needed function close_active_mi(). One can achive same thing by calling end_slave().
Added support for SHOW FULL SLAVE STATUS (show status for all master connections with connection_name as first column)
sql/slave.h:
Added new prototypes
sql/sql_base.cc:
More DBUG_PRINT
sql/sql_class.cc:
Reset thd->connection_name and thd-->default_master_connection
sql/sql_class.h:
Added thd->connection_name and thd-->default_master_connection
Added slave_skip_count to variables to make changing the @@sql_slave_skip_count variable thread safe
sql/sql_const.h:
Added MAX_CONNECTION_NAME
sql/sql_lex.cc:
Reset 'lex->verbose' (to simplify some sql_yacc.yy code)
sql/sql_lex.h:
Added connection_name
sql/sql_parse.cc:
Added support for connection_name to all SLAVE commands.
- Instead of using active_mi, we now get the current Master_info from master_info_index.
- Create new replication threads with CHANGE MASTER
- Added support for show_all_master_info()
sql/sql_reload.cc:
Made reset/full slave use master_info_index->get_master_info() instead of active_mi.
If one uses 'RESET SLAVE "connection_name" all' the connection is removed from master_info_index.
sql/sql_repl.cc:
sql_slave_skip_counter is moved to thd->variables to make it thread safe and fix some bugs with it
Add connection name to relay log files.
Added connection name to errors.
Added some logging for multi-master if log_warnings > 1
stop_slave():
- Don't check if thd is set. It's guaranteed to always be set.
change_master():
- Check for duplicate connection names in change_master()
- Check for wrong arguments first in file (to simplify error handling)
- Register new connections in master_info_index
sql/sql_yacc.yy:
Added optional connection_name to a all relevant master/slave commands
sql/strfunc.cc:
my_global.h shoud always be included first.
sql/sys_vars.cc:
Added variable default_master_connection
Made variable sql_slave_skip_counter multi-source safe
sql/sys_vars.h:
Added Sys_var_session_lexstring (needed for default_master_connection)
Added Sys_var_multi_source_uint (needed for sql_slave_skip_counter).
and small collateral changes
mysql-test/lib/My/Test.pm:
somehow with "print" we get truncated writes sometimes
mysql-test/suite/perfschema/r/digest_table_full.result:
md5 hashes of statement digests differ, because yacc token codes are different in mariadb
mysql-test/suite/perfschema/r/dml_handler.result:
host table is not ported over yet
mysql-test/suite/perfschema/r/information_schema.result:
host table is not ported over yet
mysql-test/suite/perfschema/r/nesting.result:
this differs, because we don't rewrite general log queries, and multi-statement
packets are logged as a one entry. this result file is identical to what mysql-5.6.5
produces with the --log-raw option.
mysql-test/suite/perfschema/r/relaylog.result:
MariaDB modifies the binlog index file directly, while MySQL 5.6 has a feature "crash-safe binlog index" and modifies a special "crash-safe" shadow copy of the index file and then moves it over. That's why this test shows "NONE" index file writes in MySQL and "MANY" in MariaDB.
mysql-test/suite/perfschema/r/server_init.result:
MariaDB initializes the "manager" resources from the "manager" thread, and starts this thread only when --flush-time is not 0. MySQL 5.6 initializes "manager" resources unconditionally on server startup.
mysql-test/suite/perfschema/r/stage_mdl_global.result:
this differs, because MariaDB disables query cache when query_cache_size=0. MySQL does not
do that, and this causes useless mutex locks and waits.
mysql-test/suite/perfschema/r/statement_digest.result:
md5 hashes of statement digests differ, because yacc token codes are different in mariadb
mysql-test/suite/perfschema/r/statement_digest_consumers.result:
md5 hashes of statement digests differ, because yacc token codes are different in mariadb
mysql-test/suite/perfschema/r/statement_digest_long_query.result:
md5 hashes of statement digests differ, because yacc token codes are different in mariadb
mysql-test/suite/rpl/r/rpl_mixed_drop_create_temp_table.result:
will be updated to match 5.6 when alfranio.correia@oracle.com-20110512172919-c1b5kmum4h52g0ni and anders.song@greatopensource.com-20110105052107-zoab0bsf5a6xxk2y are merged
mysql-test/suite/rpl/r/rpl_non_direct_mixed_mixing_engines.result:
will be updated to match 5.6 when anders.song@greatopensource.com-20110105052107-zoab0bsf5a6xxk2y is merged
feature_dynamic_columns,feature_fulltext,feature_gis,feature_locale,feature_subquery,feature_timezone,feature_trigger,feature_xml
Opened_views, Executed_triggers, Executed_events
Added new process status 'updating status' as part of 'freeing items'
mysql-test/r/features.result:
Test of feature_xxx status variables
mysql-test/r/mysqld--help.result:
Removed duplicated 'language' variable.
mysql-test/r/view.result:
Test of opened_views
mysql-test/suite/rpl/t/rpl_start_stop_slave.test:
Write more information on failure
mysql-test/t/features.test:
Test of feature_xxx status variables
mysql-test/t/view.test:
Test of opened_views
sql/event_scheduler.cc:
Increment executed_events status variable
sql/field.cc:
Increment status variable
sql/item_func.cc:
Increment status variable
sql/item_strfunc.cc:
Increment status variable
sql/item_subselect.cc:
Increment status variable
sql/item_xmlfunc.cc:
Increment status variable
sql/mysqld.cc:
Add new status variables to 'show status'
sql/mysqld.h:
Added executed_events
sql/sql_base.cc:
Increment status variable
sql/sql_class.h:
Add new status variables
sql/sql_parse.cc:
Added new process status 'updating status' as part of 'freeing items'
sql/sql_trigger.cc:
Increment status variable
sql/sys_vars.cc:
Increment status variable
sql/tztime.cc:
Increment status variable
Original patch by Eric Herman
client/mysql.cc:
Added LAST_VALUE
mysql-test/r/last_value.result:
Testing of LAST_VALUE
mysql-test/t/last_value.test:
Testing of LAST_VALUE
sql/item_func.cc:
Added LAST_VALUE()
sql/item_func.h:
Added LAST_VALUE()
sql/lex.h:
Added LAST_VALUE()
sql/sql_yacc.yy:
Added LAST_VALUE()
include/mysql_com.h:
remove "shutdown levels" that aren't shutdown levels from mysql_enum_shutdown_level
mysys/my_addr_resolve.c:
my_snprintf in 5.5 (but not in 5.3) supports %p
sql/item_func.cc:
use a method (that exists only in 5.5) instead of directly accessing a member
sql/item_subselect.cc:
use a method (that exists only in 5.5) instead of directly accessing a member
sql/opt_subselect.cc:
use a method (that exists only in 5.5) instead of directly accessing a member
sql/sql_select.cc:
use a method (that exists only in 5.5) instead of directly accessing a member
* rename all debugging related command-line options
and variables to start from "debug-", and made them all
OFF by default.
* replace "MySQL" with "MariaDB" in error messages
* "Cast ... converted ... integer to it's ... complement"
is now a note, not a warning
* @@query_cache_strip_comments now has a session scope,
not global.
my_double_round(DBL_MAX, -12, ....)
should return 'inf' rather than DBL_MAX
The problem is that floor(value/tmp) * tmp
is inlined, and optimized away.
The solution seems to be to prevent inlining by pre-computing value/tmp and
storing it in a variable.
No new test case: main.type_float fails without this patch.
my_double_round(DBL_MAX, -12, ....)
should return 'inf' rather than DBL_MAX
The problem is that floor(value/tmp) * tmp
is inlined, and optimized away.
The solution seems to be to prevent inlining by pre-computing value/tmp and
storing it in a variable.
No new test case: main.type_float fails without this patch.
sql/sql_insert.cc:
CREATE ... IF NOT EXISTS may do nothing, but
it is still not a failure. don't forget to my_ok it.
******
CREATE ... IF NOT EXISTS may do nothing, but
it is still not a failure. don't forget to my_ok it.
sql/sql_table.cc:
small cleanup
******
small cleanup
One can set @@global.max_user_connections to -1 to block anyone, except SUPER user, to login.
If max_user_connection is 0, one can't change it without a restart (needed to get user connections counting to work correctly)
mysql-test/r/system_mysql_db.result:
Changed max_user_connections to handle negative numbers.
mysql-test/r/user_limits-2.result:
New test case that one can't change max_user_connection if it was 0
mysql-test/r/user_limits.result:
Fixed wrong error messages.
mysql-test/r/variables.result:
Store / restore max_user_connections (needed as there is now a --master.opt file that changes it)
mysql-test/t/subselect_mat_cost-master.opt:
Enable slow query log (as this test found some errors in slow query logging)
mysql-test/t/user_limits-2.test:
New test case that one can't change max_user_connection if it was 0
mysql-test/t/user_limits-master.opt:
Set max_user_connections (as one can't change it if it was 0)
mysql-test/t/user_limits.test:
Test max_user_connections -1
mysql-test/t/variables-master.opt:
Set max_user_connections (as one can't change it if it was 0)
mysql-test/t/variables.test:
Set/restore max_user_connections
scripts/Makefile.am:
Add a text message to mysql_fix_privilege_tables.sql that it's automaticly generated
scripts/mysql_system_tables.sql:
Change max_user_connections to signed
scripts/mysql_system_tables_fix.sql:
Change max_user_connections to signed
sql/item_func.cc:
Change SHOW_INT to be signed.
(Needed for max_user_connections and it's probably a bug that it was not originally signed)
sql/log.cc:
Remove some code that was not needed (All these variables are reset at start of query)
sql/mysql_priv.h:
Made max_user_connections signed.
Added max_user_connections_checking
sql/mysqld.cc:
Added max_user_connections_checking so that we know if max_user_connections was 0 at startup
(Which means that we will not do connection counting for accounts that don't have user resource limits)
Set thd->start_utime at same time as thr_create_utime. (Before start_utime could be < thr_create_utime which lead to wrong query counting)
sql/set_var.cc:
Don't allow one to change 'max_user_connections' if it was 0 at startup.
sql/sql_acl.cc:
Change user_connection counting to be negative.
sql/sql_connect.cc:
If max_user_connections is < 0 then only SUPER user can login.
Fixed wrong variable names for error messages.
Fixed wrong initial value for questions.
Set thd->start_utime and thd->thr_create_utime at startup. Needed to get time_out_user_resource_limits() to work.
sql/sql_show.cc:
SHOW_INT is now negative
sql/sql_yacc.yy:
Support negative values for MAX_USER_CONNECTIONS
sql/structs.h:
Make user connect counting work with signed numbers.
