MySQL sys schema deep dive

2. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | Program Agenda Introduction to the MySQL sys schema Installation Formatting / Helper Routines Summary Views Tracing Routines 1 2 3 4 5

4. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | Why the sys schema? • Performance Schema exposes a huge amount of data • Many of its tables can implement multiple different use cases, depending on the type of data • The sys schema layers on top the (sometimes complex) queries in to a packaged set of easy to use views • It also adds a number of functions and procedures that help format, configure the output of, and record, Performance Schema data • Implements many of the common day to day DBA and Developer debugging and tuning use cases

6. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | Installation from the command line • $ git clone https://github.com/mysql/mysql-sys.git /tmp/sys • $ cd /tmp/sys • $ mysql -u user -p < sys_<version>.sql <version> can be 56 or 57, for 5.6 and 5.7 respectively

8. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | Installation on the new MySQL 5.7 GA • Do nothing other than install/mysql_upgrade it is there by default! • You will be able to install future upgrades from the sys repository as you wish, no restrictions there

9. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | select * from sys.version; +-------------+---------------+ | sys_version | mysql_version | +-------------+---------------+ | 1.5.1 | 5.7.14-log | +-------------+---------------+ 9 Checking sys is loaded mysql> select * -> from sys.schema_object_overview -> where db = 'sys'; +-----+---------------+-------+ | db | object_type | count | +-----+---------------+-------+ | sys | BASE TABLE | 1 | | sys | INDEX (BTREE) | 1 | | sys | TRIGGER | 2 | | sys | FUNCTION | 22 | | sys | PROCEDURE | 26 | | sys | VIEW | 100 | +-----+---------------+-------+

11. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | • Make output human readable • Format time appropriately • Format bytes appropriately • Truncate output for large width values for CLI • Extract object names • Check instrumentation state 11 Formatting / Helper Functions format_time format_bytes format_path format_statement extract_table_from_file_name extract_schema_from_file_name ps_is_account_enabled ps_is_consumer_enabled ps_is_instrument_default_enabled ps_is_instrument_default_timed ps_is_thread_instrumented

12. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | format_time() function mysql> select format_time(23849723429) as time -> union select format_time(8327423749233) -> union select format_time(83274237492335); +-------------+ | time | +-------------+ | 23.85 ms | | 8.33 s | | 00:01:23.27 | +-------------+

13. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | format_bytes() function mysql> select format_bytes(23423) as bytes -> union select format_bytes(23432423) -> union select format_bytes(42839479283) -> union select format_bytes(2293848203489); +-----------+ | bytes | +-----------+ | 22.87 KiB | | 22.35 MiB | | 39.90 GiB | | 2.09 TiB | +-----------+

14. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | Performance Schema Config Helper Procedures • ps_setup_show_disabled() / ps_setup_show_enabled() • ps_setup_disable_thread() / ps_setup_enable_thread() • ps_setup_disable_background_threads() / ps_setup_enable_background_threads() • ps_setup_disable_instrument() / ps_setup_enable_instrument() • ps_setup_disable_consumer() / ps_setup_enable_consumer() • ps_setup_save() / ps_setup_reload_saved() • ps_setup_reset_to_default() / ps_truncate_all_tables()

16. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | MySQL sys views • Reference set of views solving various administrator use cases • Simple views, create/copy your own, sys is not “locked down” • Build upon both performance_schema and INFORMATION_SCHEMA • Both formatted and raw views are available • All raw views are prefixed with x$ • Raw views are there for tools to poll • Formatted views are for humans and the command line

17. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | • High level user/host overviews • Breakdowns by: • IO usage • Stages • Statement details • Following show users only 17 User / Host Summary Views user_summary user_summary_by_file_io user_summary_by_file_io_type user_summary_by_stages user_summary_by_statement_latency user_summary_by_statement_type host_summary host_summary_by_file_io host_summary_by_file_io_type host_summary_by_stages host_summary_by_statement_latency host_summary_by_statement_type

18. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | user_summary view mysql> select * from user_summaryG *************************** 1. row *************************** user: mark statements: 3072 statement_latency: 1.77 s statement_avg_latency: 575.29 us table_scans: 7 file_ios: 20043 file_io_latency: 346.79 ms current_connections: 1 total_connections: 1 unique_hosts: 1 current_memory: 515.81 KiB total_memory_allocated: 30.69 MiB MySQL 5.7

19. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | user_summary_by_file_io_type view mysql> select * from user_summary_by_file_io_type; +------+--------------------------------------+---------+-------------+-------------+ | user | event_name | total | latency | max_latency | +------+--------------------------------------+---------+-------------+-------------+ | mark | wait/io/file/myisam/dfile | 19540 | 215.20 ms | 120.79 ms | | mark | wait/io/file/myisam/kfile | 501 | 131.58 ms | 57.74 ms | | mark | wait/io/file/sql/dbopt | 2 | 17.29 us | 9.17 us | | root | wait/io/file/innodb/innodb_log_file | 2079432 | 00:28:27.62 | 1.30 s | | root | wait/io/file/myisam/kfile | 5195927 | 00:17:07.33 | 1.17 s | | root | wait/io/file/myisam/dfile | 1533813 | 00:07:27.59 | 1.18 s | | root | wait/io/file/sql/binlog | 3517008 | 00:03:07.34 | 1.42 s | | root | wait/io/file/innodb/innodb_data_file | 20720 | 00:02:37.81 | 492.23 ms | | root | wait/io/file/sql/FRM | 41412 | 3.17 s | 80.43 ms | | root | wait/io/file/sql/dbopt | 110993 | 1.23 s | 63.27 ms |

20. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | user_summary_by_statement_latency view mysql> select * from user_summary_by_statement_latencyG *************************** 1. row *************************** user: mark total: 176 total_latency: 1.26 s max_latency: 583.33 ms lock_latency: 216.95 ms rows_sent: 311 rows_examined: 307 rows_affected: 0 full_scans: 7

21. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | user_summary_by_statement_type view mysql> select * from user_summary_by_statement_typeG *************************** 1. row *************************** user: mark statement: commit total: 2463190 total_latency: 13.33h max_latency: 12.18 s lock_latency: 0 ps rows_sent: 0 rows_examined: 0 rows_affected: 0 full_scans: 0

22. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | • IO by current threads • Global summaries by file and class, aggregating by bytes or latency • Stream of last file IO events in raw form 22 IO Summary Views io_by_thread_by_latency io_global_by_file_by_bytes io_global_by_file_by_latency io_global_by_wait_by_bytes io_global_by_wait_by_latency

23. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | io_by_thread_by_latency view mysql> select * from io_by_thread_by_latencyG *************************** 1. row *************************** user: main total: 1193 total_latency: 136.45 ms min_latency: 731.38 ns avg_latency: 269.99 us max_latency: 20.72 ms thread_id: 1 processlist_id: NULL *************************** 2. row *************************** user: root@localhost total: 533 total_latency: 53.81 ms min_latency: 780.39 ns avg_latency: 8.41 ms max_latency: 25.06 ms thread_id: 23 processlist_id: 4

24. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | io_global_by_file_by_latency view mysql> select * from io_global_by_file_by_latency limit 1G *************************** 1. row *************************** file: @@datadir/ibdata1 total: 1395714 total_latency: 00:28:53.06 count_read: 1006 read_latency: 4.51 s count_write: 1326529 write_latency: 33.39 s count_misc: 68179 misc_latency: 00:28:15.16

26. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | • Object overview • Table usage statistics • Index usage statistics • Following show users only 26 Schema Analysis Views schema_index_statistics schema_object_overview schema_table_statistics schema_table_statistics_with_buffer schema_tables_with_full_table_scans schema_unused_indexes

27. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | schema_table_statistics view mysql> select * from schema_table_statistics limit 1G *************************** 1. row *************************** table_schema: mem__quan table_name: normalized_statements_by_server_by_schema_data total_latency: 00:55:07.80 rows_fetched: 239685 fetch_latency: 17.10 s rows_inserted: 1102895 insert_latency: 00:52:18.10 rows_updated: 55910 update_latency: 00:02:28.62 rows_deleted: 17899 delete_latency: 3.98 s io_read_requests: 20639 io_read: 324.94 MiB io_read_latency: 00:03:04.10 io_write_requests: 1965973 io_write: 40.36 GiB io_write_latency: 25.46 s io_misc_requests: 18217 io_misc_latency: 00:14:06.02

28. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | schema_index_statistics view mysql> select * from schema_index_statistics limit 1G *************************** 1. row *************************** table_schema: mem__inventory table_name: mysqlconnectionconfiguration index_name: PRIMARY rows_selected: 131399 select_latency: 00:07:05.03 rows_inserted: 0 insert_latency: 0 ps rows_updated: 41608 update_latency: 21.96 s rows_deleted: 0 delete_latency: 0 ps

29. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | schema_tables_with_full_table_scans view mysql> select * from schema_tables_with_full_table_scans limit 10; +--------------------+--------------------------------+-------------------+-----------+ | object_schema | object_name | rows_full_scanned | latency | +--------------------+--------------------------------+-------------------+-----------+ | mem30__instruments | fsstatistics | 10207042 | 13.10 s | | mem30__instruments | preparedstatementapidata | 436428 | 973.27 ms | | mem30__instruments | mysqlprocessactivity | 411702 | 282.07 ms | | mem30__instruments | querycachequeriesincachedata | 374011 | 767.15 ms | | mem30__instruments | rowaccessesdata | 322321 | 1.55 s | | mem30__instruments | connectionsmaxdata | 301242 | 857.63 ms | | mem30__instruments | innodbdatadictionarymemorydata | 292564 | 495.38 ms | | mem30__instruments | innodbbufferpooldata | 277112 | 1.95 s | | mem30__instruments | avgrowaccessesdata | 269236 | 1.25 s | | mem30__instruments | innodbrowdetailsdata | 248208 | 653.25 ms | +--------------------+--------------------------------+-------------------+-----------+

31. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | • Wait summaries by class • Wait details per: • User • Host • Globally 31 Wait Analysis Views wait_classes_global_by_avg_latency wait_classes_global_by_latency waits_by_host_by_latency waits_by_user_by_latency waits_global_by_latency

32. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | waits_global_by_latency view mysql> select * from waits_global_by_latency limit 10; +--------------------------------------+----------+---------------+-------------+-------------+ | events | total | total_latency | avg_latency | max_latency | +--------------------------------------+----------+---------------+-------------+-------------+ | wait/io/table/sql/handler | 24196659 | 1.75h | 259.72 us | 2.29 s | | wait/io/file/innodb/innodb_data_file | 5964255 | 1.36h | 822.01 us | 1.49 s | | wait/io/file/innodb/innodb_log_file | 2272647 | 00:36:41.37 | 968.64 us | 1.30 s | | wait/io/file/myisam/kfile | 5463587 | 00:18:14.16 | 200.26 us | 1.17 s | | wait/io/file/myisam/dfile | 1715187 | 00:08:00.18 | 279.96 us | 1.18 s | | wait/io/file/sql/binlog | 3722079 | 00:03:23.71 | 54.73 us | 1.42 s | | wait/lock/table/sql/handler | 10074274 | 00:01:56.63 | 11.58 us | 186.90 ms | | wait/io/socket/sql/client_connection | 3879827 | 25.36 s | 6.54 us | 219.25 ms | | wait/io/file/sql/FRM | 43994 | 3.27 s | 74.35 us | 80.43 ms | | wait/io/file/sql/dbopt | 116765 | 1.29 s | 11.03 us | 63.27 ms | +--------------------------------------+----------+---------------+-------------+-------------+ InnoDB only instance, this MyISAM IO is all temporary tables, focus tuning there!

33. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | waits_by_user_by_latency view mysql> select * from waits_by_user_by_latency; +------+--------------------------------------+----------+---------------+-------------+-------------+ | user | event | total | total_latency | avg_latency | max_latency | +------+--------------------------------------+----------+---------------+-------------+-------------+ | mark | wait/io/file/myisam/dfile | 19540 | 215.20 ms | 11.01 us | 120.79 ms | | mark | wait/io/file/myisam/kfile | 501 | 131.58 ms | 262.63 us | 57.74 ms | | mark | wait/io/file/sql/dbopt | 2 | 17.29 us | 8.64 us | 9.17 us | | root | wait/io/table/sql/handler | 24189319 | 1.74h | 258.77 us | 2.29 s | | root | wait/io/file/innodb/innodb_log_file | 2162650 | 00:30:52.87 | 856.76 us | 1.30 s | | root | wait/io/file/myisam/kfile | 5460992 | 00:18:12.83 | 200.11 us | 1.17 s | | root | wait/io/file/myisam/dfile | 1694624 | 00:07:59.50 | 282.95 us | 1.18 s | | root | wait/io/file/sql/binlog | 3711637 | 00:03:23.16 | 54.74 us | 1.42 s | | root | wait/io/file/innodb/innodb_data_file | 22577 | 00:03:05.73 | 8.23 ms | 492.23 ms | | root | wait/lock/table/sql/handler | 10069000 | 00:01:56.59 | 11.58 us | 186.90 ms | …… root is doing the most temporary table IO

35. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | sys.schema_table_lock_waits mysql> select * from sys.schema_table_lock_waitsG *************************** 1. row *************************** object_schema: test object_name: t waiting_thread_id: 43 waiting_pid: 21 waiting_account: msandbox@localhost waiting_lock_type: SHARED_UPGRADABLE waiting_lock_duration: TRANSACTION waiting_query: alter table test.t add foo int waiting_query_secs: 988 waiting_query_rows_affected: 0 waiting_query_rows_examined: 0 blocking_thread_id: 42 blocking_pid: 20 blocking_account: msandbox@localhost blocking_lock_type: SHARED_NO_READ_WRITE blocking_lock_duration: TRANSACTION sql_kill_blocking_query: KILL QUERY 20 sql_kill_blocking_connection: KILL 20

36. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | sys.innodb_lock_waits mysql> SELECT * FROM sys.innodb_lock_waitsG *************************** 1. row *************************** wait_started: 2014-11-11 13:39:20 wait_age: 00:00:07 wait_age_secs: 7 locked_table: `db1`.`t1` locked_index: PRIMARY locked_type: RECORD waiting_trx_id: 867158 waiting_trx_started: 2014-11-11 13:39:15 waiting_trx_age: 00:00:12 waiting_trx_rows_locked: 0 waiting_trx_rows_modified: 0 waiting_pid: 3 waiting_query: UPDATE t1 SET val = val + 1 WHERE id = 2 waiting_lock_id: 867158:2363:3:3 waiting_lock_mode: X blocking_trx_id: 867157 blocking_pid: 4 ... blocking_query: UPDATE t1 SET val … blocking_lock_id: 867157:2363:3:3 blocking_lock_mode: X blocking_trx_started: 2014-11-11 13:39:11 blocking_trx_age: 00:00:16 blocking_trx_rows_locked: 1 blocking_trx_rows_modified: 1 sql_kill_blocking_query: KILL QUERY 4 sql_kill_blocking_connection: KILL 4

37. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | • Statement overview • Find statements by: • Those with errors • Those with full table scans • Those creating temp tables • Those that cause sorting • With latency in 95th %ile 37 Statement Analysis Views statement_analysis statements_with_errors_or_warnings statements_with_full_table_scans statements_with_runtimes_in_95th_p ercentile statements_with_sorting statements_with_temp_tables

38. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | statement_analysis view mysql> select * from statement_analysis limit 2G *************************** 1. row *************************** query: INSERT INTO `mem30__quan` . `n ... nDuration` = IF ( VALUES ( ... db: mem full_scan: exec_count: 4657 err_count: 0 warn_count: 0 total_latency: 00:03:57.40 max_latency: 10.54 s avg_latency: 50.98 ms lock_latency: 00:03:00.93 rows_sent: 0 rows_sent_avg: 0 rows_examined: 0 rows_examined_avg: 0 rows_affected: 4794 rows_affected_avg: 1 tmp_tables: 0 tmp_disk_tables: 0 rows_sorted: 0 sort_merge_passes: 0 digest: b98bfe333642e8e4e72c73515810d865 first_seen: 2014-09-24 11:27:01 last_seen: 2014-09-24 11:53:00

39. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | statements_with_errors_or_warnings view mysql> select * from statements_with_errors_or_warnings limit 1G *************************** 1. row *************************** query: CREATE TEMPORARY TABLE IF NOT ... _logs` ( `id` INT8 NOT NULL ) db: mem exec_count: 1725 errors: 1725 error_pct: 100.0000 warnings: 0 warning_pct: 0.0000 first_seen: 2014-05-20 10:42:32 last_seen: 2014-05-21 18:39:22 digest: 51fb979dbc3910a6294c7cdabd7839c3

40. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | statements_with_temp_tables view mysql> select * from statements_with_temp_tables limit 1G *************************** 1. row *************************** query: SELECT * FROM ( SELECT `digest ... ` , `sum_no_index_used` AS ... db: mysql exec_count: 68 total_latency: 2.31 s memory_tmp_tables: 476 disk_tmp_tables: 204 avg_tmp_tables_per_query: 7 tmp_tables_to_disk_pct: 43 first_seen: 2014-09-24 11:26:18 last_seen: 2014-09-24 12:33:00 digest: 50761c6a1818824328745d8a136b9ed6

41. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | statements_with_full_table_scans view mysql> select * from statements_with_full_table_scans limit 1G *************************** 1. row *************************** query: SELECT `pojotimese0_` . `id` A ... ty_timeseries` `pojotimese0_` db: mem exec_count: 1 total_latency: 940.89 us no_index_used_count: 1 no_good_index_used_count: 0 no_index_used_pct: 100 rows_sent: 116 rows_examined: 116 rows_sent_avg: 116 rows_examined_avg: 116 first_seen: 2014-09-24 11:25:03 last_seen: 2014-09-24 11:25:03 digest: f81b5ce10baee9be754cf35fd245a516

42. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | • Expose summary memory usage by host, thread and user • Show global usage • Based on Performance Schema memory instruments (disabled by default, these need enabling) 42 Memory Views memory_by_host_by_current_bytes memory_by_thread_by_current_bytes memory_by_user_by_current_bytes memory_global_by_current_bytes memory_global_total

43. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | memory_global_by_current_bytes view mysql> select * from sys.memory_global_by_current_bytes limit 5G *************************** 1. row *************************** event_name: memory/innodb/buf_buf_pool current_count: 6 current_alloc: 785.62 MiB current_avg_alloc: 130.94 MiB high_count: 6 high_alloc: 785.62 MiB high_avg_alloc: 130.94 MiB *************************** 2. row *************************** event_name: memory/innodb/os0file current_count: 431 current_alloc: 52.51 MiB current_avg_alloc: 124.76 KiB high_count: 434 … InnoDB Buffer Pool InnoDB file IO memory usage (various)

44. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | memory_by_thread_by_current_bytes view mysql> select * from sys.memory_by_thread_by_current_bytes -> where user not like 'innodb%' and user not like 'sql%'; +-----------+----------------+--------------------+-------------------+-------------------+-------------------+-----------------+ | thread_id | user | current_count_used | current_allocated | current_avg_alloc | current_max_alloc | total_allocated | +-----------+----------------+--------------------+-------------------+-------------------+-------------------+-----------------+ | 176167 | root@localhost | 67 | 633.36 KiB | 9.45 KiB | 256.00 KiB | 246.06 MiB | | 176220 | root@localhost | 67 | 246.73 KiB | 3.68 KiB | 73.46 KiB | 10.34 MiB | | 176223 | root@localhost | 48 | 192.12 KiB | 4.00 KiB | 64.10 KiB | 1.03 MiB | | 176221 | root@localhost | 49 | 180.79 KiB | 3.69 KiB | 64.10 KiB | 766.13 KiB | | 176224 | root@localhost | 58 | 169.58 KiB | 2.92 KiB | 64.10 KiB | 4.26 MiB | | 176225 | root@localhost | 83 | 159.06 KiB | 1.92 KiB | 64.10 KiB | 4.38 MiB | | 176217 | root@localhost | 56 | 149.91 KiB | 2.68 KiB | 64.10 KiB | 5.75 MiB | | 176226 | root@localhost | 68 | 148.90 KiB | 2.19 KiB | 64.10 KiB | 2.80 MiB | | 176205 | root@localhost | 41 | 148.06 KiB | 3.61 KiB | 64.10 KiB | 5.08 MiB | | 176204 | root@localhost | 51 | 143.25 KiB | 2.81 KiB | 64.10 KiB | 11.22 MiB | | 176222 | root@localhost | 73 | 139.38 KiB | 1.91 KiB | 64.10 KiB | 1.46 MiB | | 176201 | root@localhost | -33 | 122.04 KiB | -3787 bytes | 64.10 KiB | 14.55 MiB | Note values can go negative if threads allocate memory, but pass it to another thread to be freed, this thread has freed memory from another thread

45. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | • Better SHOW PROCESSLIST • No mutex contention • Live statistics for query • Consolidated metrics 45 Miscellaneous Views processlist session metrics

46. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | processlist / session views mysql> select * from sessionG *************************** 1. row *************************** thd_id: 7890 conn_id: 7870 user: root@localhost db: mem command: Query state: update time: 0 current_statement: /* mem dbpool.default */ inser ...<truncated> lock_latency: 0 ps rows_examined: 0 rows_sent: 0 rows_affected: 0 tmp_tables: 0 tmp_disk_tables: 0 full_scan: NO last_statement: NULL last_statement_latency: NULL last_wait: wait/io/table/sql/handler last_wait_latency: Still Waiting source: handler.cc:7274

47. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | sys.sessions progress estimationmysql> select * from sys.sessionsG *************************** 1. row *************************** thd_id: 44524 conn_id: 44502 user: msandbox@localhost db: test command: Query state: alter table (flush) time: 18 current_statement: alter table t1 add column g int statement_latency: 18.45 s progress: 98.84 lock_latency: 265.43 ms rows_examined: 0 rows_sent: 0 rows_affected: 0 tmp_tables: 0 tmp_disk_tables: 0 ...

48. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | sys.metrics mysql> select * from sys.metrics limit 199, 10; +-----------------------------+----------------+--------------------------------------+---------+ | Variable_name | Variable_value | Type | Enabled | +-----------------------------+----------------+--------------------------------------+---------+ | tc_log_page_waits | 0 | Global Status | YES | | threads_cached | 7 | Global Status | YES | | threads_connected | 3 | Global Status | YES | | threads_created | 10 | Global Status | YES | | threads_running | 3 | Global Status | YES | | uptime | 275689 | Global Status | YES | | uptime_since_flush_status | 275689 | Global Status | YES | | adaptive_hash_pages_added | 0 | InnoDB Metrics - adaptive_hash_index | NO | | adaptive_hash_pages_removed | 0 | InnoDB Metrics - adaptive_hash_index | NO | | adaptive_hash_rows_added | 0 | InnoDB Metrics - adaptive_hash_index | NO | +-----------------------------+----------------+--------------------------------------+---------+ performance_schema.global_status information_schema.innodb_metrics

50. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | • Dump all P_S data to a dot graph file to trace a thread • Look in the statement history table to capture more info on a statement digest • Show detailed transaction info • Dump as much diagnostics info as possible (support enabler) 50 Statement Tracing Routines ps_trace_thread ps_trace_statement_digest ps_thread_trx_info ps_thread_stack ps_statement_avg_latency_histogram diagnostics

51. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | ps_trace_statement_digest procedure • ps_trace_statement_digest() analyses live traffic looking for certain statement digest for a period of time • Captures statistics on each matching statement it finds • Returns a report of the captured stats • An overall summary • A break down for the longest running example • An EXPLAIN (if the statement is not truncated)

52. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | ps_trace_statement_digest procedure • ps_trace_statement_digest() parameters • in_digest The statement digest to analyse • in_runtime How long to run analysis for • in_interval How often to snapshot data • in_start_fresh Whether to truncate P_S tables first • in_auto_enable Whether to auto enable required config

53. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | ps_trace_statement_digest procedure example mysql> call ps_trace_statement_digest(‘6134e9d6f25eb8e6cddf11f6938f202a’, 60, 1, true, true); +--------------------+ | SUMMARY STATISTICS | +--------------------+ | SUMMARY STATISTICS | +--------------------+ 1 row in set (59.93 sec) +------------+-----------+-----------+-----------+---------------+------------+------------+ | executions | exec_time | lock_time | rows_sent | rows_examined | tmp_tables | full_scans | +------------+-----------+-----------+-----------+---------------+------------+------------+ | 360 | 1.41 s | 138.39 ms | 720 | 0 | 0 | 0 | +------------+-----------+-----------+-----------+---------------+------------+------------+ 1 row in set (59.93 sec) +--------------------------------+-------+-----------+ | event_name | count | latency | +--------------------------------+-------+-----------+ | stage/sql/Sending data | 14 | 1.10 s | | stage/sql/update | 198 | 667.34 ms | | stage/sql/removing tmp table | 9 | 240.48 ms | ...

54. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | ps_trace_statement_digest procedure example +---------------------------+ | LONGEST RUNNING STATEMENT | +---------------------------+ | LONGEST RUNNING STATEMENT | +---------------------------+ 1 row in set (59.95 sec) +-----------+-----------+-----------+-----------+---------------+------------+-----------+ | thread_id | exec_time | lock_time | rows_sent | rows_examined | tmp_tables | full_scan | +-----------+-----------+-----------+-----------+---------------+------------+-----------+ | 23277 | 77.64 ms | 97.00 us | 2 | 0 | 0 | 0 | +-----------+-----------+-----------+-----------+---------------+------------+-----------+ 1 row in set (59.95 sec) +-------------------------------------------------------------------------------------------+ | sql_text | +-------------------------------------------------------------------------------------------+ | /* mem dbpool.default */ insert into `mem__quan`.`normalized_statements_by_server_by_schema` (firstSeen, lastSeen, normalized_statement_id, `schema`, server, id) values (1378983745000, 1378998600000, x'808ACEB88FC4B45BC47C4FE9D86C7F26', 'mem', '753c939e-1b99-11e3-b6d4-bc761a1f4f2f', x'7CFE81F98B1E3FE0895D1AA2C39B326D') ON DUPLICATE KEY UPDATE ... +-------------------------------------------------------------------------------------------+ ...

56. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | sys.ps_thread_trx_info(<thread_id>) SELECT sys.ps_thread_trx_info(48) as trx_infoG *************************** 1. row *************************** trx_info: [ { "time": "790.70 us", "state": "COMMITTED", "mode": "READ WRITE", "autocommitted": "NO", "gtid": "AUTOMATIC", "isolation": "REPEATABLE READ", "statements_executed": [ { "sql_text": "INSERT INTO info VALUES (1, 'foo')", "time": "471.02 us", "schema": "trx", "rows_examined": 0, "rows_affected": 1, "rows_sent": 0, "tmp_tables": 0, "tmp_disk_tables": 0, "sort_rows": 0, "sort_merge_passes": 0 }, ... Pass in thread id

57. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | ps_trace_thread procedure • ps_trace_thread() monitors a specific thread for a period • Captures as much information on the thread activity as possible • Returns a “dot” formatted file, that can graph the event hierarchy • http://en.wikipedia.org/wiki/DOT_(graph_description_language)

58. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | ps_trace_thread procedure • ps_trace_thread parameters • in_thread_id The thread to analyse • in_outfile The file to dump the data to (INTO OUTFILE) • in_max_runtime How long to run analysis for • in_interval How often to snapshot for data • in_start_fresh Whether to truncate P_S tables first • in_auto_setup Whether to auto enable required config • in_debug Whether to also print debug info (source info)

59. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | ps_trace_thread procedure example mysql> call ps_trace_thread(27768, '/tmp/stack_27768.dot', 60, 0.1, true, true, true); +------------------------------------------------+ | Info | +------------------------------------------------+ | Data collection starting for THREAD_ID = 27768 | +------------------------------------------------+ 1 row in set (4.82 sec) +---------------------------------------------+ | Info | +---------------------------------------------+ | Stack trace written to /tmp/stack_27768.dot | +---------------------------------------------+ 1 row in set (60.90 sec) +--------------------------------------------------------+ | Convert to PDF | +--------------------------------------------------------+ | dot -Tpdf -o /tmp/stack_27768.pdf /tmp/stack_27768.dot | +--------------------------------------------------------+ 1 row in set (60.90 sec) +--------------------------------------------------------+ | Convert to PNG | +--------------------------------------------------------+ | dot -Tpng -o /tmp/stack_27768.png /tmp/stack_27768.dot | +--------------------------------------------------------+ 1 row in set (60.90 sec)+

60. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | ps_trace_thread procedure example cerberus:~ mark$ more Documents/statement_graphs/deletes.dot digraph events { graph [rankdir=LR, nodesep="0.10"]; node [label="N"]; graph [bb="0,0,1860,17476"]; 1 [label="(0.20μ) mysys/THR_LOCK_threadsn", style=filled, color=lightskyblue, pos="209,18", width="3.19", height="0.50"]; 2 [label="(0.18μ) sql/THD::LOCK_thd_datan", style=filled, color=lightskyblue, pos="209,61", width="3.06", height="0.50"]; 3 [label="(0.24μ) sql/hash_filo::lockn", style=filled, color=lightskyblue, pos="209,104", width="2.42", height=“0.50"]; 4 [label="(0.31μ) sql/LOGGER::LOCK_logger - read_lockn", style=filled, color=orchid, pos="209,147", width="4.22", height="0.50"]; 5 [label="(0.08μ) sql/LOG::LOCK_logn", style=filled, color=lightskyblue, pos="209,190", width="2.64", height="0.50"]; 6 [label="(12.97μ) wait/io/file/sql/query_log - write 49 bytesn/Users/mark/mysql/lp-mysql-trunk/mysql-test/var/mysqld.1/ mysqld.logn", style=filled, color=red, shape=box, pos="209,235", width="5.78", height="0.56"]; 7 [label="(176.14μ) sql/selectnselect @@version_comment limit 1nerrors: 0nwarnings: 0nlock time: 0.00μnrows affected: 0nrows sent: 209,18", width="3.19", height="0.50"];mp disk tables: 0nselect scan: 0nselect full join: : 2 [label="(0.18μ) sql/THD::LOCK_thd_datan", style=filled, color=lightskyblue, pos="209,61", width="3.06", height="0.50"]; 3 [label="(0.24μ) sql/hash_filo::lockn", style=filled, color=lightskyblue, pos="209,104", width="2.42", height="0.50"]; 4 [label="(0.31μ) sql/LOGGER::LOCK_logger - read_lockn", style=filled, color=orchid, pos="209,147", width="4.22", height="0.50"]; 5 [label="(0.08μ) sql/LOG::LOCK_logn", style=filled, color=lightskyblue, pos="209,190", width="2.64", height="0.50"]; ……

69. Copyright © 2014, Oracle and/or its affiliates. All rights reserved. | Safe Harbor Statement The preceding is intended to outline our general product direction. It is intended for information purposes only, and may not be incorporated into any contract. It is not a commitment to deliver any material, code, or functionality, and should not be relied upon in making purchasing decisions. The development, release, and timing of any features or functionality described for Oracle’s products remains at the sole discretion of Oracle.

MySQL sys schema deep dive

Mark Leith

MySQL sys schema deep dive