show databases;
Database
information_schema
mtr
mysql
performance_schema
sys
test
select count(*) from performance_schema.performance_timers;
count(*)
5
select count(*) from performance_schema.setup_consumers;
count(*)
15
select count(*) > 4 from performance_schema.setup_instruments;
count(*) > 4
1
select count(*) from performance_schema.setup_timers;
count(*)
5
Warnings:
Warning	1681	'performance_schema.setup_timers' is deprecated and will be removed in a future release.
select * from performance_schema.accounts;
select * from performance_schema.cond_instances;
select * from performance_schema.events_stages_current;
select * from performance_schema.events_stages_history;
select * from performance_schema.events_stages_history_long;
select * from performance_schema.events_stages_summary_by_account_by_event_name;
select * from performance_schema.events_stages_summary_by_host_by_event_name;
select * from performance_schema.events_stages_summary_by_thread_by_event_name;
select * from performance_schema.events_stages_summary_by_user_by_event_name;
select * from performance_schema.events_stages_summary_global_by_event_name;
select * from performance_schema.events_statements_current;
select * from performance_schema.events_statements_history;
select * from performance_schema.events_statements_history_long;
select * from performance_schema.events_statements_summary_by_account_by_event_name;
select * from performance_schema.events_statements_summary_by_digest;
select * from performance_schema.events_statements_summary_by_host_by_event_name;
select * from performance_schema.events_statements_summary_by_thread_by_event_name;
select * from performance_schema.events_statements_summary_by_user_by_event_name;
select * from performance_schema.events_statements_summary_global_by_event_name;
select * from performance_schema.events_transactions_current;
select * from performance_schema.events_transactions_history;
select * from performance_schema.events_transactions_history_long;
select * from performance_schema.events_transactions_summary_by_account_by_event_name;
select * from performance_schema.events_transactions_summary_by_host_by_event_name;
select * from performance_schema.events_transactions_summary_by_thread_by_event_name;
select * from performance_schema.events_transactions_summary_by_user_by_event_name;
select * from performance_schema.events_transactions_summary_global_by_event_name;
select * from performance_schema.events_waits_current;
select * from performance_schema.events_waits_history;
select * from performance_schema.events_waits_history_long;
select * from performance_schema.events_waits_summary_by_account_by_event_name;
select * from performance_schema.events_waits_summary_by_host_by_event_name;
select * from performance_schema.events_waits_summary_by_instance;
select * from performance_schema.events_waits_summary_by_thread_by_event_name;
select * from performance_schema.events_waits_summary_by_user_by_event_name;
select * from performance_schema.events_waits_summary_global_by_event_name;
select * from performance_schema.memory_summary_by_account_by_event_name;
select * from performance_schema.memory_summary_by_host_by_event_name;
select * from performance_schema.memory_summary_by_thread_by_event_name;
select * from performance_schema.memory_summary_by_user_by_event_name;
select * from performance_schema.memory_summary_global_by_event_name;
select * from performance_schema.file_instances;
select * from performance_schema.file_summary_by_event_name;
select * from performance_schema.file_summary_by_instance;
select * from performance_schema.host_cache;
select * from performance_schema.hosts;
select * from performance_schema.memory_summary_by_account_by_event_name;
select * from performance_schema.memory_summary_by_host_by_event_name;
select * from performance_schema.memory_summary_by_thread_by_event_name;
select * from performance_schema.memory_summary_by_user_by_event_name;
select * from performance_schema.memory_summary_global_by_event_name;
select * from performance_schema.metadata_locks;
select * from performance_schema.mutex_instances;
select * from performance_schema.objects_summary_global_by_type;
select * from performance_schema.performance_timers;
select * from performance_schema.rwlock_instances;
select * from performance_schema.session_account_connect_attrs;
select * from performance_schema.session_connect_attrs;
select * from performance_schema.setup_actors;
select * from performance_schema.setup_consumers;
select * from performance_schema.setup_instruments;
select * from performance_schema.setup_objects;
select * from performance_schema.setup_timers;
select * from performance_schema.socket_instances;
select * from performance_schema.socket_summary_by_instance;
select * from performance_schema.socket_summary_by_event_name;
select * from performance_schema.table_handles;
select * from performance_schema.table_io_waits_summary_by_index_usage;
select * from performance_schema.table_io_waits_summary_by_table;
select * from performance_schema.table_lock_waits_summary_by_table;
select * from performance_schema.threads;
select * from performance_schema.users;
select * from performance_schema.replication_connection_configuration;
select * from performance_schema.replication_connection_status;
select * from performance_schema.replication_applier_configuration;
select * from performance_schema.replication_applier_status;
select * from performance_schema.replication_applier_status_by_coordinator;
select * from performance_schema.replication_applier_status_by_worker;
select * from performance_schema.global_status;
select * from performance_schema.status_by_thread;
select * from performance_schema.status_by_user;
select * from performance_schema.status_by_host;
select * from performance_schema.status_by_account;
select * from performance_schema.session_status;
select * from performance_schema.global_variables;
select * from performance_schema.variables_by_thread;
select * from performance_schema.session_variables;
show global variables like "performance_schema%";
Variable_name	Value
performance_schema	ON
performance_schema_accounts_size	100
performance_schema_digests_size	200
performance_schema_events_stages_history_long_size	1000
performance_schema_events_stages_history_size	10
performance_schema_events_statements_history_long_size	1000
performance_schema_events_statements_history_size	10
performance_schema_events_transactions_history_long_size	1000
performance_schema_events_transactions_history_size	10
performance_schema_events_waits_history_long_size	10000
performance_schema_events_waits_history_size	10
performance_schema_hosts_size	100
performance_schema_max_cond_classes	80
performance_schema_max_cond_instances	-1
performance_schema_max_digest_length	1024
performance_schema_max_file_classes	80
performance_schema_max_file_handles	32768
performance_schema_max_file_instances	-1
performance_schema_max_index_stat	-1
performance_schema_max_memory_classes	320
performance_schema_max_metadata_locks	-1
performance_schema_max_mutex_classes	210
performance_schema_max_mutex_instances	-1
performance_schema_max_prepared_statements_instances	0
performance_schema_max_program_instances	-1
performance_schema_max_rwlock_classes	50
performance_schema_max_rwlock_instances	-1
performance_schema_max_socket_classes	10
performance_schema_max_socket_instances	-1
performance_schema_max_sql_text_length	1024
performance_schema_max_stage_classes	150
performance_schema_max_statement_classes	193
performance_schema_max_statement_stack	10
performance_schema_max_table_handles	-1
performance_schema_max_table_instances	-1
performance_schema_max_table_lock_stat	-1
performance_schema_max_thread_classes	50
performance_schema_max_thread_instances	-1
performance_schema_session_connect_attrs_size	2048
performance_schema_setup_actors_size	100
performance_schema_setup_objects_size	100
performance_schema_show_processlist	OFF
performance_schema_users_size	100
show engine PERFORMANCE_SCHEMA status;
show global status like "performance_schema%";
CREATE DATABASE db;
USE db;
show global variables like "performance_schema_max_prepared_statements_instances";
Variable_name	Value
performance_schema_max_prepared_statements_instances	0
select count(*) from performance_schema.prepared_statements_instances;
count(*)
0
truncate table performance_schema.prepared_statements_instances;
CREATE TABLE t1 (a INT NOT NULL);
INSERT INTO t1 VALUES (4), (8), (11), (32), (80);
PREPARE st1 FROM 'SELECT SQRT(POW(?,2) + POW(?,2)) AS hypotenuse';
SET @table = 't1';
SET @s = CONCAT('SELECT * FROM ', @table);
PREPARE st2 FROM @s;
PREPARE st3 FROM 'INSERT INTO t1 SELECT * FROM t1 WHERE a<=?';
PREPARE st4 FROM
'(SELECT a FROM t1) UNION (SELECT a+10 FROM t1) ORDER BY RAND()*0+a';
show global status like "%performance_schema_prepared_statements_lost%";
Variable_name	Value
Performance_schema_prepared_statements_lost	4
SET @a = 3;
SET @b = 4;
EXECUTE st1 USING @a, @b;
hypotenuse
5
EXECUTE st2;
a
4
8
11
32
80
SET @c=3;
EXECUTE st3 using @c;
EXECUTE st4;
a
4
8
11
14
18
21
32
42
80
90
show global status like "%performance_schema_prepared_statements_lost%";
Variable_name	Value
Performance_schema_prepared_statements_lost	4
DEALLOCATE PREPARE st1;
DEALLOCATE PREPARE st2;
DEALLOCATE PREPARE st3;
DEALLOCATE PREPARE st4;
DROP TABLE t1;
show global status like "%performance_schema_prepared_statements_lost%";
Variable_name	Value
Performance_schema_prepared_statements_lost	4
flush status;
show global status like "%performance_schema_prepared_statements_lost%";
Variable_name	Value
Performance_schema_prepared_statements_lost	0
DROP DATABASE db;