2001-09-28 07:05:54 +02:00
|
|
|
flush status;
|
|
|
|
show status like 'Table_lock%';
|
2001-01-27 04:00:42 +01:00
|
|
|
Variable_name Value
|
WL#3984 (Revise locking of mysql.general_log and mysql.slow_log)
Bug#25422 (Hang with log tables)
Bug 17876 (Truncating mysql.slow_log in a SP after using cursor locks the
thread)
Bug 23044 (Warnings on flush of a log table)
Bug 29129 (Resetting general_log while the GLOBAL READ LOCK is set causes
a deadlock)
Prior to this fix, the server would hang when performing concurrent
ALTER TABLE or TRUNCATE TABLE statements against the LOG TABLES,
which are mysql.general_log and mysql.slow_log.
The root cause traces to the following code:
in sql_base.cc, open_table()
if (table->in_use != thd)
{
/* wait_for_condition will unlock LOCK_open for us */
wait_for_condition(thd, &LOCK_open, &COND_refresh);
}
The problem with this code is that the current implementation of the
LOGGER creates 'fake' THD objects, like
- Log_to_csv_event_handler::general_log_thd
- Log_to_csv_event_handler::slow_log_thd
which are not associated to a real thread running in the server,
so that waiting for these non-existing threads to release table locks
cause the dead lock.
In general, the design of Log_to_csv_event_handler does not fit into the
general architecture of the server, so that the concept of general_log_thd
and slow_log_thd has to be abandoned:
- this implementation does not work with table locking
- it will not work with commands like SHOW PROCESSLIST
- having the log tables always opened does not integrate well with DDL
operations / FLUSH TABLES / SET GLOBAL READ_ONLY
With this patch, the fundamental design of the LOGGER has been changed to:
- always open and close a log table when writing a log
- remove totally the usage of fake THD objects
- clarify how locking of log tables is implemented in general.
See WL#3984 for details related to the new locking design.
Additional changes (misc bugs exposed and fixed):
1)
mysqldump which would ignore some tables in dump_all_tables_in_db(),
but forget to ignore the same in dump_all_views_in_db().
2)
mysqldump would also issue an empty "LOCK TABLE" command when all the tables
to lock are to be ignored (numrows == 0), instead of not issuing the query.
3)
Internal errors handlers could intercept errors but not warnings
(see sql_error.cc).
4)
Implementing a nested call to open tables, for the performance schema tables,
exposed an existing bug in remove_table_from_cache(), which would perform:
in_use->some_tables_deleted=1;
against another thread, without any consideration about thread locking.
This call inside remove_table_from_cache() was not required anyway,
since calling mysql_lock_abort() takes care of aborting -- cleanly -- threads
that might hold a lock on a table.
This line (in_use->some_tables_deleted=1) has been removed.
sql/handler.cc:
Moved logic for system / log tables in the SQL layer.
sql/handler.h:
Moved logic for system / log tables in the SQL layer.
sql/lock.cc:
Revised locking of log tables
sql/log.cc:
Major cleanup: changed how log tables are locked / written to.
sql/log.h:
Major cleanup: changed how log tables are locked / written to.
sql/mysql_priv.h:
performance schema helpers
sql/slave.cc:
open_ltable() lock flags
sql/sp.cc:
open_ltable() lock flags
sql/sql_acl.cc:
open_ltable() lock flags
sql/sql_class.h:
performance schema helpers
sql/sql_delete.cc:
log tables cleanup in TRUNCATE
sql/sql_error.cc:
Internal handlers can also intercept warnings
sql/sql_insert.cc:
open_ltable() lock flags
sql/sql_parse.cc:
performance schema helpers
sql/sql_plugin.cc:
open_ltable() lock flags
sql/sql_rename.cc:
log tables cleanup in RENAME
sql/sql_servers.cc:
open_ltable() lock flags
sql/sql_show.cc:
Move INFORMATION_SCHEMA_NAME to table.cc
sql/sql_table.cc:
log tables cleanup (admin operations, ALTER TABLE)
sql/sql_udf.cc:
open_ltable() lock flags
sql/table.cc:
Implemented TABLE_CATEGORY.
sql/share/errmsg.txt:
Changed the wording and name of ER_CANT_READ_LOCK_LOG_TABLE
sql/table.h:
Implemented TABLE_CATEGORY.
storage/csv/ha_tina.cc:
Moved logic for system / log tables in the SQL layer.
storage/csv/ha_tina.h:
Moved logic for system / log tables in the SQL layer.
storage/myisam/ha_myisam.cc:
Moved logic for system / log tables in the SQL layer.
storage/myisam/ha_myisam.h:
Moved logic for system / log tables in the SQL layer.
client/mysqldump.c:
Don't lock tables in the ignore list.
Don't issue empty LOCK TABLES queries.
sql/sql_base.cc:
log tables cleanup
performance schema helpers
mysql-test/r/ps.result:
Adjust test results
mysql-test/r/show_check.result:
Adjust test results
mysql-test/r/status.result:
Adjust test results
mysql-test/t/log_state.test:
Added tests for Bug#29129
mysql-test/t/ps.test:
Make the test output deterministic
mysql-test/t/show_check.test:
Make the test output deterministic
mysql-test/r/log_state.result:
Changed the default location of the log output to LOG_FILE,
for backward compatibility with MySQL 5.0
---
Adjust test results
mysql-test/r/log_tables.result:
cleanup for -ps-protocol
mysql-test/t/log_tables.test:
cleanup for -ps-protocol
sql/set_var.cc:
Changed the default location of the log output to LOG_FILE,
for backward compatibility with MySQL 5.0
---
log tables cleanup
2007-07-27 08:31:06 +02:00
|
|
|
Table_locks_immediate 1
|
2001-01-27 04:00:42 +01:00
|
|
|
Table_locks_waited 0
|
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
mysql-test/r/information_schema.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed test cases result (changes are due to the new tables added).
mysql-test/r/information_schema_db.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed test cases result (changes are due to the new tables added).
mysql-test/r/status.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed results for added testcases.
mysql-test/r/variables.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed results for added test cases.
mysql-test/t/status.test:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Added test cases.
mysql-test/t/variables.test:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Added test cases.
sql/sql_show.cc:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Implementation of the new I_S tables.
Also, show_status_array(): argument 'ucase_names' is added (true means that
all variable names are to be converted to upper case).
sql/table.h:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Implementation of the new I_S tables.
2006-09-14 01:37:40 +02:00
|
|
|
select * from information_schema.session_status where variable_name like 'Table_lock%';
|
|
|
|
VARIABLE_NAME VARIABLE_VALUE
|
WL#3984 (Revise locking of mysql.general_log and mysql.slow_log)
Bug#25422 (Hang with log tables)
Bug 17876 (Truncating mysql.slow_log in a SP after using cursor locks the
thread)
Bug 23044 (Warnings on flush of a log table)
Bug 29129 (Resetting general_log while the GLOBAL READ LOCK is set causes
a deadlock)
Prior to this fix, the server would hang when performing concurrent
ALTER TABLE or TRUNCATE TABLE statements against the LOG TABLES,
which are mysql.general_log and mysql.slow_log.
The root cause traces to the following code:
in sql_base.cc, open_table()
if (table->in_use != thd)
{
/* wait_for_condition will unlock LOCK_open for us */
wait_for_condition(thd, &LOCK_open, &COND_refresh);
}
The problem with this code is that the current implementation of the
LOGGER creates 'fake' THD objects, like
- Log_to_csv_event_handler::general_log_thd
- Log_to_csv_event_handler::slow_log_thd
which are not associated to a real thread running in the server,
so that waiting for these non-existing threads to release table locks
cause the dead lock.
In general, the design of Log_to_csv_event_handler does not fit into the
general architecture of the server, so that the concept of general_log_thd
and slow_log_thd has to be abandoned:
- this implementation does not work with table locking
- it will not work with commands like SHOW PROCESSLIST
- having the log tables always opened does not integrate well with DDL
operations / FLUSH TABLES / SET GLOBAL READ_ONLY
With this patch, the fundamental design of the LOGGER has been changed to:
- always open and close a log table when writing a log
- remove totally the usage of fake THD objects
- clarify how locking of log tables is implemented in general.
See WL#3984 for details related to the new locking design.
Additional changes (misc bugs exposed and fixed):
1)
mysqldump which would ignore some tables in dump_all_tables_in_db(),
but forget to ignore the same in dump_all_views_in_db().
2)
mysqldump would also issue an empty "LOCK TABLE" command when all the tables
to lock are to be ignored (numrows == 0), instead of not issuing the query.
3)
Internal errors handlers could intercept errors but not warnings
(see sql_error.cc).
4)
Implementing a nested call to open tables, for the performance schema tables,
exposed an existing bug in remove_table_from_cache(), which would perform:
in_use->some_tables_deleted=1;
against another thread, without any consideration about thread locking.
This call inside remove_table_from_cache() was not required anyway,
since calling mysql_lock_abort() takes care of aborting -- cleanly -- threads
that might hold a lock on a table.
This line (in_use->some_tables_deleted=1) has been removed.
sql/handler.cc:
Moved logic for system / log tables in the SQL layer.
sql/handler.h:
Moved logic for system / log tables in the SQL layer.
sql/lock.cc:
Revised locking of log tables
sql/log.cc:
Major cleanup: changed how log tables are locked / written to.
sql/log.h:
Major cleanup: changed how log tables are locked / written to.
sql/mysql_priv.h:
performance schema helpers
sql/slave.cc:
open_ltable() lock flags
sql/sp.cc:
open_ltable() lock flags
sql/sql_acl.cc:
open_ltable() lock flags
sql/sql_class.h:
performance schema helpers
sql/sql_delete.cc:
log tables cleanup in TRUNCATE
sql/sql_error.cc:
Internal handlers can also intercept warnings
sql/sql_insert.cc:
open_ltable() lock flags
sql/sql_parse.cc:
performance schema helpers
sql/sql_plugin.cc:
open_ltable() lock flags
sql/sql_rename.cc:
log tables cleanup in RENAME
sql/sql_servers.cc:
open_ltable() lock flags
sql/sql_show.cc:
Move INFORMATION_SCHEMA_NAME to table.cc
sql/sql_table.cc:
log tables cleanup (admin operations, ALTER TABLE)
sql/sql_udf.cc:
open_ltable() lock flags
sql/table.cc:
Implemented TABLE_CATEGORY.
sql/share/errmsg.txt:
Changed the wording and name of ER_CANT_READ_LOCK_LOG_TABLE
sql/table.h:
Implemented TABLE_CATEGORY.
storage/csv/ha_tina.cc:
Moved logic for system / log tables in the SQL layer.
storage/csv/ha_tina.h:
Moved logic for system / log tables in the SQL layer.
storage/myisam/ha_myisam.cc:
Moved logic for system / log tables in the SQL layer.
storage/myisam/ha_myisam.h:
Moved logic for system / log tables in the SQL layer.
client/mysqldump.c:
Don't lock tables in the ignore list.
Don't issue empty LOCK TABLES queries.
sql/sql_base.cc:
log tables cleanup
performance schema helpers
mysql-test/r/ps.result:
Adjust test results
mysql-test/r/show_check.result:
Adjust test results
mysql-test/r/status.result:
Adjust test results
mysql-test/t/log_state.test:
Added tests for Bug#29129
mysql-test/t/ps.test:
Make the test output deterministic
mysql-test/t/show_check.test:
Make the test output deterministic
mysql-test/r/log_state.result:
Changed the default location of the log output to LOG_FILE,
for backward compatibility with MySQL 5.0
---
Adjust test results
mysql-test/r/log_tables.result:
cleanup for -ps-protocol
mysql-test/t/log_tables.test:
cleanup for -ps-protocol
sql/set_var.cc:
Changed the default location of the log output to LOG_FILE,
for backward compatibility with MySQL 5.0
---
log tables cleanup
2007-07-27 08:31:06 +02:00
|
|
|
TABLE_LOCKS_IMMEDIATE 2
|
2007-05-15 09:45:50 +02:00
|
|
|
TABLE_LOCKS_WAITED 0
|
2001-09-28 07:05:54 +02:00
|
|
|
SET SQL_LOG_BIN=0;
|
|
|
|
drop table if exists t1;
|
2003-12-10 05:31:42 +01:00
|
|
|
create table t1(n int) engine=myisam;
|
2001-09-28 07:05:54 +02:00
|
|
|
insert into t1 values(1);
|
|
|
|
lock tables t1 read;
|
|
|
|
unlock tables;
|
|
|
|
lock tables t1 read;
|
|
|
|
update t1 set n = 3;
|
|
|
|
unlock tables;
|
2007-08-18 10:28:08 +02:00
|
|
|
show status like 'Table_locks_waited';
|
2001-01-27 04:00:42 +01:00
|
|
|
Variable_name Value
|
|
|
|
Table_locks_waited 1
|
2001-09-28 07:05:54 +02:00
|
|
|
drop table t1;
|
2005-09-06 12:00:35 +02:00
|
|
|
select 1;
|
|
|
|
1
|
|
|
|
1
|
|
|
|
show status like 'last_query_cost';
|
|
|
|
Variable_name Value
|
|
|
|
Last_query_cost 0.000000
|
2006-06-20 12:20:32 +02:00
|
|
|
create table t1 (a int);
|
|
|
|
insert into t1 values (1),(2),(3),(4),(5),(6),(7),(8),(9),(10);
|
|
|
|
insert into t1 values (1),(2),(3),(4),(5),(6),(7),(8),(9),(10);
|
|
|
|
insert into t1 values (1),(2),(3),(4),(5),(6),(7),(8),(9),(10);
|
|
|
|
insert into t1 values (1),(2),(3),(4),(5),(6),(7),(8),(9),(10);
|
|
|
|
insert into t1 values (1),(2),(3),(4),(5),(6),(7),(8),(9),(10);
|
|
|
|
select * from t1 where a=6;
|
|
|
|
a
|
|
|
|
6
|
|
|
|
6
|
|
|
|
6
|
|
|
|
6
|
|
|
|
6
|
|
|
|
show status like 'last_query_cost';
|
|
|
|
Variable_name Value
|
|
|
|
Last_query_cost 12.084449
|
|
|
|
show status like 'last_query_cost';
|
|
|
|
Variable_name Value
|
|
|
|
Last_query_cost 12.084449
|
|
|
|
select 1;
|
|
|
|
1
|
|
|
|
1
|
|
|
|
show status like 'last_query_cost';
|
|
|
|
Variable_name Value
|
|
|
|
Last_query_cost 0.000000
|
|
|
|
drop table t1;
|
2006-04-07 13:30:40 +02:00
|
|
|
FLUSH STATUS;
|
|
|
|
SHOW STATUS LIKE 'max_used_connections';
|
|
|
|
Variable_name Value
|
2006-07-04 18:44:35 +02:00
|
|
|
Max_used_connections 1
|
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
mysql-test/r/information_schema.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed test cases result (changes are due to the new tables added).
mysql-test/r/information_schema_db.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed test cases result (changes are due to the new tables added).
mysql-test/r/status.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed results for added testcases.
mysql-test/r/variables.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed results for added test cases.
mysql-test/t/status.test:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Added test cases.
mysql-test/t/variables.test:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Added test cases.
sql/sql_show.cc:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Implementation of the new I_S tables.
Also, show_status_array(): argument 'ucase_names' is added (true means that
all variable names are to be converted to upper case).
sql/table.h:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Implementation of the new I_S tables.
2006-09-14 01:37:40 +02:00
|
|
|
SELECT * FROM INFORMATION_SCHEMA.SESSION_STATUS WHERE VARIABLE_NAME LIKE 'max_used_connections';
|
|
|
|
VARIABLE_NAME VARIABLE_VALUE
|
2007-05-15 09:45:50 +02:00
|
|
|
MAX_USED_CONNECTIONS 1
|
2006-04-07 13:30:40 +02:00
|
|
|
SET @save_thread_cache_size=@@thread_cache_size;
|
|
|
|
SET GLOBAL thread_cache_size=3;
|
|
|
|
SHOW STATUS LIKE 'max_used_connections';
|
|
|
|
Variable_name Value
|
2006-07-04 18:44:35 +02:00
|
|
|
Max_used_connections 3
|
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
mysql-test/r/information_schema.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed test cases result (changes are due to the new tables added).
mysql-test/r/information_schema_db.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed test cases result (changes are due to the new tables added).
mysql-test/r/status.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed results for added testcases.
mysql-test/r/variables.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed results for added test cases.
mysql-test/t/status.test:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Added test cases.
mysql-test/t/variables.test:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Added test cases.
sql/sql_show.cc:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Implementation of the new I_S tables.
Also, show_status_array(): argument 'ucase_names' is added (true means that
all variable names are to be converted to upper case).
sql/table.h:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Implementation of the new I_S tables.
2006-09-14 01:37:40 +02:00
|
|
|
SELECT * FROM INFORMATION_SCHEMA.SESSION_STATUS WHERE VARIABLE_NAME LIKE 'max_used_connections';
|
|
|
|
VARIABLE_NAME VARIABLE_VALUE
|
2007-05-15 09:45:50 +02:00
|
|
|
MAX_USED_CONNECTIONS 3
|
2006-04-07 13:30:40 +02:00
|
|
|
FLUSH STATUS;
|
|
|
|
SHOW STATUS LIKE 'max_used_connections';
|
|
|
|
Variable_name Value
|
2006-07-04 18:44:35 +02:00
|
|
|
Max_used_connections 2
|
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
mysql-test/r/information_schema.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed test cases result (changes are due to the new tables added).
mysql-test/r/information_schema_db.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed test cases result (changes are due to the new tables added).
mysql-test/r/status.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed results for added testcases.
mysql-test/r/variables.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed results for added test cases.
mysql-test/t/status.test:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Added test cases.
mysql-test/t/variables.test:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Added test cases.
sql/sql_show.cc:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Implementation of the new I_S tables.
Also, show_status_array(): argument 'ucase_names' is added (true means that
all variable names are to be converted to upper case).
sql/table.h:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Implementation of the new I_S tables.
2006-09-14 01:37:40 +02:00
|
|
|
SELECT * FROM INFORMATION_SCHEMA.SESSION_STATUS WHERE VARIABLE_NAME LIKE 'max_used_connections';
|
|
|
|
VARIABLE_NAME VARIABLE_VALUE
|
2007-05-15 09:45:50 +02:00
|
|
|
MAX_USED_CONNECTIONS 2
|
2006-04-07 13:30:40 +02:00
|
|
|
SHOW STATUS LIKE 'max_used_connections';
|
|
|
|
Variable_name Value
|
2006-07-04 18:44:35 +02:00
|
|
|
Max_used_connections 3
|
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
mysql-test/r/information_schema.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed test cases result (changes are due to the new tables added).
mysql-test/r/information_schema_db.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed test cases result (changes are due to the new tables added).
mysql-test/r/status.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed results for added testcases.
mysql-test/r/variables.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed results for added test cases.
mysql-test/t/status.test:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Added test cases.
mysql-test/t/variables.test:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Added test cases.
sql/sql_show.cc:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Implementation of the new I_S tables.
Also, show_status_array(): argument 'ucase_names' is added (true means that
all variable names are to be converted to upper case).
sql/table.h:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Implementation of the new I_S tables.
2006-09-14 01:37:40 +02:00
|
|
|
SELECT * FROM INFORMATION_SCHEMA.SESSION_STATUS WHERE VARIABLE_NAME LIKE 'max_used_connections';
|
|
|
|
VARIABLE_NAME VARIABLE_VALUE
|
2007-05-15 09:45:50 +02:00
|
|
|
MAX_USED_CONNECTIONS 3
|
2006-05-23 12:10:07 +02:00
|
|
|
SHOW STATUS LIKE 'max_used_connections';
|
|
|
|
Variable_name Value
|
2006-07-04 18:44:35 +02:00
|
|
|
Max_used_connections 4
|
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
mysql-test/r/information_schema.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed test cases result (changes are due to the new tables added).
mysql-test/r/information_schema_db.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed test cases result (changes are due to the new tables added).
mysql-test/r/status.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed results for added testcases.
mysql-test/r/variables.result:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Fixed results for added test cases.
mysql-test/t/status.test:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Added test cases.
mysql-test/t/variables.test:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Added test cases.
sql/sql_show.cc:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Implementation of the new I_S tables.
Also, show_status_array(): argument 'ucase_names' is added (true means that
all variable names are to be converted to upper case).
sql/table.h:
WL#3247,#3248: Adding [GLOBAL|SESSION]_STATUS and [GLOBAL|SESSION]_VARIABLES
tables to INFORMATION_SCHEMA.
Implementation of the new I_S tables.
2006-09-14 01:37:40 +02:00
|
|
|
SELECT * FROM INFORMATION_SCHEMA.SESSION_STATUS WHERE VARIABLE_NAME LIKE 'max_used_connections';
|
|
|
|
VARIABLE_NAME VARIABLE_VALUE
|
2007-05-15 09:45:50 +02:00
|
|
|
MAX_USED_CONNECTIONS 4
|
2006-04-07 13:30:40 +02:00
|
|
|
SET GLOBAL thread_cache_size=@save_thread_cache_size;
|
2007-08-28 17:51:03 +02:00
|
|
|
CREATE TABLE t1 ( a INT );
|
|
|
|
INSERT INTO t1 VALUES (1), (2);
|
|
|
|
SELECT a FROM t1 LIMIT 1;
|
|
|
|
a
|
|
|
|
1
|
|
|
|
SHOW SESSION STATUS LIKE 'Last_query_cost';
|
|
|
|
Variable_name Value
|
|
|
|
Last_query_cost 2.402418
|
|
|
|
EXPLAIN SELECT a FROM t1;
|
|
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
|
|
1 SIMPLE t1 ALL NULL NULL NULL NULL 2
|
|
|
|
SHOW SESSION STATUS LIKE 'Last_query_cost';
|
|
|
|
Variable_name Value
|
|
|
|
Last_query_cost 2.402418
|
|
|
|
SELECT a FROM t1 UNION SELECT a FROM t1 ORDER BY a;
|
|
|
|
a
|
|
|
|
1
|
|
|
|
2
|
|
|
|
SHOW SESSION STATUS LIKE 'Last_query_cost';
|
|
|
|
Variable_name Value
|
|
|
|
Last_query_cost 0.000000
|
|
|
|
EXPLAIN SELECT a FROM t1 UNION SELECT a FROM t1 ORDER BY a;
|
|
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
|
|
1 PRIMARY t1 ALL NULL NULL NULL NULL 2
|
|
|
|
2 UNION t1 ALL NULL NULL NULL NULL 2
|
|
|
|
NULL UNION RESULT <union1,2> ALL NULL NULL NULL NULL NULL Using filesort
|
|
|
|
SHOW SESSION STATUS LIKE 'Last_query_cost';
|
|
|
|
Variable_name Value
|
|
|
|
Last_query_cost 0.000000
|
|
|
|
SELECT a IN (SELECT a FROM t1) FROM t1 LIMIT 1;
|
|
|
|
a IN (SELECT a FROM t1)
|
|
|
|
1
|
|
|
|
SHOW SESSION STATUS LIKE 'Last_query_cost';
|
|
|
|
Variable_name Value
|
|
|
|
Last_query_cost 0.000000
|
|
|
|
SELECT (SELECT a FROM t1 LIMIT 1) x FROM t1 LIMIT 1;
|
|
|
|
x
|
|
|
|
1
|
|
|
|
SHOW SESSION STATUS LIKE 'Last_query_cost';
|
|
|
|
Variable_name Value
|
|
|
|
Last_query_cost 0.000000
|
|
|
|
SELECT * FROM t1 a, t1 b LIMIT 1;
|
|
|
|
a a
|
|
|
|
1 1
|
|
|
|
SHOW SESSION STATUS LIKE 'Last_query_cost';
|
|
|
|
Variable_name Value
|
|
|
|
Last_query_cost 4.805836
|
|
|
|
DROP TABLE t1;
|
2006-06-20 12:20:32 +02:00
|
|
|
show status like 'com_show_status';
|
|
|
|
Variable_name Value
|
|
|
|
Com_show_status 3
|
|
|
|
show status like 'hand%write%';
|
|
|
|
Variable_name Value
|
WL#3984 (Revise locking of mysql.general_log and mysql.slow_log)
Bug#25422 (Hang with log tables)
Bug 17876 (Truncating mysql.slow_log in a SP after using cursor locks the
thread)
Bug 23044 (Warnings on flush of a log table)
Bug 29129 (Resetting general_log while the GLOBAL READ LOCK is set causes
a deadlock)
Prior to this fix, the server would hang when performing concurrent
ALTER TABLE or TRUNCATE TABLE statements against the LOG TABLES,
which are mysql.general_log and mysql.slow_log.
The root cause traces to the following code:
in sql_base.cc, open_table()
if (table->in_use != thd)
{
/* wait_for_condition will unlock LOCK_open for us */
wait_for_condition(thd, &LOCK_open, &COND_refresh);
}
The problem with this code is that the current implementation of the
LOGGER creates 'fake' THD objects, like
- Log_to_csv_event_handler::general_log_thd
- Log_to_csv_event_handler::slow_log_thd
which are not associated to a real thread running in the server,
so that waiting for these non-existing threads to release table locks
cause the dead lock.
In general, the design of Log_to_csv_event_handler does not fit into the
general architecture of the server, so that the concept of general_log_thd
and slow_log_thd has to be abandoned:
- this implementation does not work with table locking
- it will not work with commands like SHOW PROCESSLIST
- having the log tables always opened does not integrate well with DDL
operations / FLUSH TABLES / SET GLOBAL READ_ONLY
With this patch, the fundamental design of the LOGGER has been changed to:
- always open and close a log table when writing a log
- remove totally the usage of fake THD objects
- clarify how locking of log tables is implemented in general.
See WL#3984 for details related to the new locking design.
Additional changes (misc bugs exposed and fixed):
1)
mysqldump which would ignore some tables in dump_all_tables_in_db(),
but forget to ignore the same in dump_all_views_in_db().
2)
mysqldump would also issue an empty "LOCK TABLE" command when all the tables
to lock are to be ignored (numrows == 0), instead of not issuing the query.
3)
Internal errors handlers could intercept errors but not warnings
(see sql_error.cc).
4)
Implementing a nested call to open tables, for the performance schema tables,
exposed an existing bug in remove_table_from_cache(), which would perform:
in_use->some_tables_deleted=1;
against another thread, without any consideration about thread locking.
This call inside remove_table_from_cache() was not required anyway,
since calling mysql_lock_abort() takes care of aborting -- cleanly -- threads
that might hold a lock on a table.
This line (in_use->some_tables_deleted=1) has been removed.
sql/handler.cc:
Moved logic for system / log tables in the SQL layer.
sql/handler.h:
Moved logic for system / log tables in the SQL layer.
sql/lock.cc:
Revised locking of log tables
sql/log.cc:
Major cleanup: changed how log tables are locked / written to.
sql/log.h:
Major cleanup: changed how log tables are locked / written to.
sql/mysql_priv.h:
performance schema helpers
sql/slave.cc:
open_ltable() lock flags
sql/sp.cc:
open_ltable() lock flags
sql/sql_acl.cc:
open_ltable() lock flags
sql/sql_class.h:
performance schema helpers
sql/sql_delete.cc:
log tables cleanup in TRUNCATE
sql/sql_error.cc:
Internal handlers can also intercept warnings
sql/sql_insert.cc:
open_ltable() lock flags
sql/sql_parse.cc:
performance schema helpers
sql/sql_plugin.cc:
open_ltable() lock flags
sql/sql_rename.cc:
log tables cleanup in RENAME
sql/sql_servers.cc:
open_ltable() lock flags
sql/sql_show.cc:
Move INFORMATION_SCHEMA_NAME to table.cc
sql/sql_table.cc:
log tables cleanup (admin operations, ALTER TABLE)
sql/sql_udf.cc:
open_ltable() lock flags
sql/table.cc:
Implemented TABLE_CATEGORY.
sql/share/errmsg.txt:
Changed the wording and name of ER_CANT_READ_LOCK_LOG_TABLE
sql/table.h:
Implemented TABLE_CATEGORY.
storage/csv/ha_tina.cc:
Moved logic for system / log tables in the SQL layer.
storage/csv/ha_tina.h:
Moved logic for system / log tables in the SQL layer.
storage/myisam/ha_myisam.cc:
Moved logic for system / log tables in the SQL layer.
storage/myisam/ha_myisam.h:
Moved logic for system / log tables in the SQL layer.
client/mysqldump.c:
Don't lock tables in the ignore list.
Don't issue empty LOCK TABLES queries.
sql/sql_base.cc:
log tables cleanup
performance schema helpers
mysql-test/r/ps.result:
Adjust test results
mysql-test/r/show_check.result:
Adjust test results
mysql-test/r/status.result:
Adjust test results
mysql-test/t/log_state.test:
Added tests for Bug#29129
mysql-test/t/ps.test:
Make the test output deterministic
mysql-test/t/show_check.test:
Make the test output deterministic
mysql-test/r/log_state.result:
Changed the default location of the log output to LOG_FILE,
for backward compatibility with MySQL 5.0
---
Adjust test results
mysql-test/r/log_tables.result:
cleanup for -ps-protocol
mysql-test/t/log_tables.test:
cleanup for -ps-protocol
sql/set_var.cc:
Changed the default location of the log output to LOG_FILE,
for backward compatibility with MySQL 5.0
---
log tables cleanup
2007-07-27 08:31:06 +02:00
|
|
|
Handler_write 5
|
2006-06-20 12:20:32 +02:00
|
|
|
show status like '%tmp%';
|
|
|
|
Variable_name Value
|
|
|
|
Created_tmp_disk_tables 0
|
|
|
|
Created_tmp_files 0
|
|
|
|
Created_tmp_tables 0
|
|
|
|
show status like 'hand%write%';
|
|
|
|
Variable_name Value
|
WL#3984 (Revise locking of mysql.general_log and mysql.slow_log)
Bug#25422 (Hang with log tables)
Bug 17876 (Truncating mysql.slow_log in a SP after using cursor locks the
thread)
Bug 23044 (Warnings on flush of a log table)
Bug 29129 (Resetting general_log while the GLOBAL READ LOCK is set causes
a deadlock)
Prior to this fix, the server would hang when performing concurrent
ALTER TABLE or TRUNCATE TABLE statements against the LOG TABLES,
which are mysql.general_log and mysql.slow_log.
The root cause traces to the following code:
in sql_base.cc, open_table()
if (table->in_use != thd)
{
/* wait_for_condition will unlock LOCK_open for us */
wait_for_condition(thd, &LOCK_open, &COND_refresh);
}
The problem with this code is that the current implementation of the
LOGGER creates 'fake' THD objects, like
- Log_to_csv_event_handler::general_log_thd
- Log_to_csv_event_handler::slow_log_thd
which are not associated to a real thread running in the server,
so that waiting for these non-existing threads to release table locks
cause the dead lock.
In general, the design of Log_to_csv_event_handler does not fit into the
general architecture of the server, so that the concept of general_log_thd
and slow_log_thd has to be abandoned:
- this implementation does not work with table locking
- it will not work with commands like SHOW PROCESSLIST
- having the log tables always opened does not integrate well with DDL
operations / FLUSH TABLES / SET GLOBAL READ_ONLY
With this patch, the fundamental design of the LOGGER has been changed to:
- always open and close a log table when writing a log
- remove totally the usage of fake THD objects
- clarify how locking of log tables is implemented in general.
See WL#3984 for details related to the new locking design.
Additional changes (misc bugs exposed and fixed):
1)
mysqldump which would ignore some tables in dump_all_tables_in_db(),
but forget to ignore the same in dump_all_views_in_db().
2)
mysqldump would also issue an empty "LOCK TABLE" command when all the tables
to lock are to be ignored (numrows == 0), instead of not issuing the query.
3)
Internal errors handlers could intercept errors but not warnings
(see sql_error.cc).
4)
Implementing a nested call to open tables, for the performance schema tables,
exposed an existing bug in remove_table_from_cache(), which would perform:
in_use->some_tables_deleted=1;
against another thread, without any consideration about thread locking.
This call inside remove_table_from_cache() was not required anyway,
since calling mysql_lock_abort() takes care of aborting -- cleanly -- threads
that might hold a lock on a table.
This line (in_use->some_tables_deleted=1) has been removed.
sql/handler.cc:
Moved logic for system / log tables in the SQL layer.
sql/handler.h:
Moved logic for system / log tables in the SQL layer.
sql/lock.cc:
Revised locking of log tables
sql/log.cc:
Major cleanup: changed how log tables are locked / written to.
sql/log.h:
Major cleanup: changed how log tables are locked / written to.
sql/mysql_priv.h:
performance schema helpers
sql/slave.cc:
open_ltable() lock flags
sql/sp.cc:
open_ltable() lock flags
sql/sql_acl.cc:
open_ltable() lock flags
sql/sql_class.h:
performance schema helpers
sql/sql_delete.cc:
log tables cleanup in TRUNCATE
sql/sql_error.cc:
Internal handlers can also intercept warnings
sql/sql_insert.cc:
open_ltable() lock flags
sql/sql_parse.cc:
performance schema helpers
sql/sql_plugin.cc:
open_ltable() lock flags
sql/sql_rename.cc:
log tables cleanup in RENAME
sql/sql_servers.cc:
open_ltable() lock flags
sql/sql_show.cc:
Move INFORMATION_SCHEMA_NAME to table.cc
sql/sql_table.cc:
log tables cleanup (admin operations, ALTER TABLE)
sql/sql_udf.cc:
open_ltable() lock flags
sql/table.cc:
Implemented TABLE_CATEGORY.
sql/share/errmsg.txt:
Changed the wording and name of ER_CANT_READ_LOCK_LOG_TABLE
sql/table.h:
Implemented TABLE_CATEGORY.
storage/csv/ha_tina.cc:
Moved logic for system / log tables in the SQL layer.
storage/csv/ha_tina.h:
Moved logic for system / log tables in the SQL layer.
storage/myisam/ha_myisam.cc:
Moved logic for system / log tables in the SQL layer.
storage/myisam/ha_myisam.h:
Moved logic for system / log tables in the SQL layer.
client/mysqldump.c:
Don't lock tables in the ignore list.
Don't issue empty LOCK TABLES queries.
sql/sql_base.cc:
log tables cleanup
performance schema helpers
mysql-test/r/ps.result:
Adjust test results
mysql-test/r/show_check.result:
Adjust test results
mysql-test/r/status.result:
Adjust test results
mysql-test/t/log_state.test:
Added tests for Bug#29129
mysql-test/t/ps.test:
Make the test output deterministic
mysql-test/t/show_check.test:
Make the test output deterministic
mysql-test/r/log_state.result:
Changed the default location of the log output to LOG_FILE,
for backward compatibility with MySQL 5.0
---
Adjust test results
mysql-test/r/log_tables.result:
cleanup for -ps-protocol
mysql-test/t/log_tables.test:
cleanup for -ps-protocol
sql/set_var.cc:
Changed the default location of the log output to LOG_FILE,
for backward compatibility with MySQL 5.0
---
log tables cleanup
2007-07-27 08:31:06 +02:00
|
|
|
Handler_write 7
|
2006-06-20 12:20:32 +02:00
|
|
|
show status like '%tmp%';
|
|
|
|
Variable_name Value
|
|
|
|
Created_tmp_disk_tables 0
|
|
|
|
Created_tmp_files 0
|
|
|
|
Created_tmp_tables 0
|
|
|
|
show status like 'com_show_status';
|
|
|
|
Variable_name Value
|
|
|
|
Com_show_status 8
|
|
|
|
rnd_diff tmp_table_diff
|
|
|
|
20 8
|