### 28.4.1 sys Schema Object Index

 The following tables list [`sys`](sys-schema.html) schema objects and provide a short description of each one.

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**Table 28.1 sys Schema Tables and Triggers**

|                       Table or Trigger Name                       |             Description              |
|-------------------------------------------------------------------|--------------------------------------|
|                [`sys_config`](sys-sys-config.html)                |sys schema configuration options table|
|[`sys_config_insert_set_user`](sys-sys-config-insert-set-user.html)|      sys\_config insert trigger      |
|[`sys_config_update_set_user`](sys-sys-config-update-set-user.html)|      sys\_config update trigger      |

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**Table 28.2 sys Schema Views**

|                                                                      View Name                                                                       |                         Description                          |Deprecated|
|------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------|----------|
|                                              [`host_summary`, `x$host_summary`](sys-host-summary.html)                                               |Statement activity, file I/O, and connections, grouped by host|          |
|                              [`host_summary_by_file_io`, `x$host_summary_by_file_io`](sys-host-summary-by-file-io.html)                              |                  File I/O, grouped by host                   |          |
|                      [`host_summary_by_file_io_type`, `x$host_summary_by_file_io_type`](sys-host-summary-by-file-io-type.html)                       |           File I/O, grouped by host and event type           |          |
|                               [`host_summary_by_stages`, `x$host_summary_by_stages`](sys-host-summary-by-stages.html)                                |              Statement stages, grouped by host               |          |
|               [`host_summary_by_statement_latency`, `x$host_summary_by_statement_latency`](sys-host-summary-by-statement-latency.html)               |            Statement statistics, grouped by host             |          |
|                   [`host_summary_by_statement_type`, `x$host_summary_by_statement_type`](sys-host-summary-by-statement-type.html)                    |      Statements executed, grouped by host and statement      |          |
|                     [`innodb_buffer_stats_by_schema`, `x$innodb_buffer_stats_by_schema`](sys-innodb-buffer-stats-by-schema.html)                     |         InnoDB buffer information, grouped by schema         |          |
|                      [`innodb_buffer_stats_by_table`, `x$innodb_buffer_stats_by_table`](sys-innodb-buffer-stats-by-table.html)                       |    InnoDB buffer information, grouped by schema and table    |          |
|                                       [`innodb_lock_waits`, `x$innodb_lock_waits`](sys-innodb-lock-waits.html)                                       |                   InnoDB lock information                    |          |
|                              [`io_by_thread_by_latency`, `x$io_by_thread_by_latency`](sys-io-by-thread-by-latency.html)                              |               I/O consumers, grouped by thread               |          |
|                         [`io_global_by_file_by_bytes`, `x$io_global_by_file_by_bytes`](sys-io-global-by-file-by-bytes.html)                          |       Global I/O consumers, grouped by file and bytes        |          |
|                      [`io_global_by_file_by_latency`, `x$io_global_by_file_by_latency`](sys-io-global-by-file-by-latency.html)                       |      Global I/O consumers, grouped by file and latency       |          |
|                         [`io_global_by_wait_by_bytes`, `x$io_global_by_wait_by_bytes`](sys-io-global-by-wait-by-bytes.html)                          |            Global I/O consumers, grouped by bytes            |          |
|                      [`io_global_by_wait_by_latency`, `x$io_global_by_wait_by_latency`](sys-io-global-by-wait-by-latency.html)                       |           Global I/O consumers, grouped by latency           |          |
|                                           [`latest_file_io`, `x$latest_file_io`](sys-latest-file-io.html)                                            |         Most recent I/O, grouped by file and thread          |          |
|                  [`memory_by_host_by_current_bytes`, `x$memory_by_host_by_current_bytes`](sys-memory-by-host-by-current-bytes.html)                  |                 Memory use, grouped by host                  |          |
|               [`memory_by_thread_by_current_bytes`, `x$memory_by_thread_by_current_bytes`](sys-memory-by-thread-by-current-bytes.html)               |                Memory use, grouped by thread                 |          |
|                  [`memory_by_user_by_current_bytes`, `x$memory_by_user_by_current_bytes`](sys-memory-by-user-by-current-bytes.html)                  |                 Memory use, grouped by user                  |          |
|                   [`memory_global_by_current_bytes`, `x$memory_global_by_current_bytes`](sys-memory-global-by-current-bytes.html)                    |            Memory use, grouped by allocation type            |          |
|                                    [`memory_global_total`, `x$memory_global_total`](sys-memory-global-total.html)                                    |                       Total memory use                       |          |
|                                                            [`metrics`](sys-metrics.html)                                                             |                        Server metrics                        |          |
|                                                [`processlist`, `x$processlist`](sys-processlist.html)                                                |                   Processlist information                    |          |
|                                      [`ps_check_lost_instrumentation`](sys-ps-check-lost-instrumentation.html)                                       |             Variables that have lost instruments             |          |
|                                      [`schema_auto_increment_columns`](sys-schema-auto-increment-columns.html)                                       |              AUTO\_INCREMENT column information              |          |
|                              [`schema_index_statistics`, `x$schema_index_statistics`](sys-schema-index-statistics.html)                              |                       Index statistics                       |          |
|                                             [`schema_object_overview`](sys-schema-object-overview.html)                                              |             Types of objects within each schema              |          |
|                                           [`schema_redundant_indexes`](sys-schema-redundant-indexes.html)                                            |                Duplicate or redundant indexes                |          |
|                              [`schema_table_lock_waits`, `x$schema_table_lock_waits`](sys-schema-table-lock-waits.html)                              |             Sessions waiting for metadata locks              |          |
|                              [`schema_table_statistics`, `x$schema_table_statistics`](sys-schema-table-statistics.html)                              |                       Table statistics                       |          |
|            [`schema_table_statistics_with_buffer`, `x$schema_table_statistics_with_buffer`](sys-schema-table-statistics-with-buffer.html)            |  Table statistics, including InnoDB buffer pool statistics   |          |
|            [`schema_tables_with_full_table_scans`, `x$schema_tables_with_full_table_scans`](sys-schema-tables-with-full-table-scans.html)            |            Tables being accessed with full scans             |          |
|                                              [`schema_unused_indexes`](sys-schema-unused-indexes.html)                                               |                  Indexes not in active use                   |          |
|                                                      [`session`, `x$session`](sys-session.html)                                                      |          Processlist information for user sessions           |          |
|                                                 [`session_ssl_status`](sys-session-ssl-status.html)                                                  |                  Connection SSL information                  |          |
|                                     [`statement_analysis`, `x$statement_analysis`](sys-statement-analysis.html)                                      |                Statement aggregate statistics                |          |
|             [`statements_with_errors_or_warnings`, `x$statements_with_errors_or_warnings`](sys-statements-with-errors-or-warnings.html)              |       Statements that have produced errors or warnings       |          |
|                [`statements_with_full_table_scans`, `x$statements_with_full_table_scans`](sys-statements-with-full-table-scans.html)                 |          Statements that have done full table scans          |          |
|[`statements_with_runtimes_in_95th_percentile`, `x$statements_with_runtimes_in_95th_percentile`](sys-statements-with-runtimes-in-95th-percentile.html)|           Statements with highest average runtime            |          |
|                              [`statements_with_sorting`, `x$statements_with_sorting`](sys-statements-with-sorting.html)                              |               Statements that performed sorts                |          |
|                        [`statements_with_temp_tables`, `x$statements_with_temp_tables`](sys-statements-with-temp-tables.html)                        |            Statements that used temporary tables             |          |
|                                              [`user_summary`, `x$user_summary`](sys-user-summary.html)                                               |            User statement and connection activity            |          |
|                              [`user_summary_by_file_io`, `x$user_summary_by_file_io`](sys-user-summary-by-file-io.html)                              |                  File I/O, grouped by user                   |          |
|                      [`user_summary_by_file_io_type`, `x$user_summary_by_file_io_type`](sys-user-summary-by-file-io-type.html)                       |             File I/O, grouped by user and event              |          |
|                               [`user_summary_by_stages`, `x$user_summary_by_stages`](sys-user-summary-by-stages.html)                                |                Stage events, grouped by user                 |          |
|               [`user_summary_by_statement_latency`, `x$user_summary_by_statement_latency`](sys-user-summary-by-statement-latency.html)               |            Statement statistics, grouped by user             |          |
|                   [`user_summary_by_statement_type`, `x$user_summary_by_statement_type`](sys-user-summary-by-statement-type.html)                    |      Statements executed, grouped by user and statement      |          |
|                                                            [`version`](sys-version.html)                                                             |         Current sys schema and MySQL server versions         |  8.0.18  |
|             [`wait_classes_global_by_avg_latency`, `x$wait_classes_global_by_avg_latency`](sys-wait-classes-global-by-avg-latency.html)              |      Wait class average latency, grouped by event class      |          |
|                   [`wait_classes_global_by_latency`, `x$wait_classes_global_by_latency`](sys-wait-classes-global-by-latency.html)                    |       Wait class total latency, grouped by event class       |          |
|                            [`waits_by_host_by_latency`, `x$waits_by_host_by_latency`](sys-waits-by-host-by-latency.html)                             |            Wait events, grouped by host and event            |          |
|                            [`waits_by_user_by_latency`, `x$waits_by_user_by_latency`](sys-waits-by-user-by-latency.html)                             |            Wait events, grouped by user and event            |          |
|                              [`waits_global_by_latency`, `x$waits_global_by_latency`](sys-waits-global-by-latency.html)                              |                Wait events, grouped by event                 |          |
|                           [`x$ps_digest_95th_percentile_by_avg_us`](sys-statements-with-runtimes-in-95th-percentile.html)                            |            Helper view for 95th-percentile views             |          |
|                            [`x$ps_digest_avg_latency_distribution`](sys-statements-with-runtimes-in-95th-percentile.html)                            |            Helper view for 95th-percentile views             |          |
|                                        [`x$ps_schema_table_statistics_io`](sys-schema-table-statistics.html)                                         |            Helper view for table-statistics views            |          |
|                                            [`x$schema_flattened_keys`](sys-schema-redundant-indexes.html)                                            |          Helper view for schema\_redundant\_indexes          |          |

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**Table 28.3 sys Schema Stored Procedures**

|                                    Procedure Name                                     |                    Description                    |
|---------------------------------------------------------------------------------------|---------------------------------------------------|
|                  [`create_synonym_db()`](sys-create-synonym-db.html)                  |             Create synonym for schema             |
|                        [`diagnostics()`](sys-diagnostics.html)                        |       Collect system diagnostic information       |
|              [`execute_prepared_stmt()`](sys-execute-prepared-stmt.html)              |            Execute prepared statement             |
|[`ps_setup_disable_background_threads()`](sys-ps-setup-disable-background-threads.html)|     Disable background thread instrumentation     |
|          [`ps_setup_disable_consumer()`](sys-ps-setup-disable-consumer.html)          |                 Disable consumers                 |
|        [`ps_setup_disable_instrument()`](sys-ps-setup-disable-instrument.html)        |                Disable instruments                |
|            [`ps_setup_disable_thread()`](sys-ps-setup-disable-thread.html)            |        Disable instrumentation for thread         |
| [`ps_setup_enable_background_threads()`](sys-ps-setup-enable-background-threads.html) |     Enable background thread instrumentation      |
|           [`ps_setup_enable_consumer()`](sys-ps-setup-enable-consumer.html)           |                 Enable consumers                  |
|         [`ps_setup_enable_instrument()`](sys-ps-setup-enable-instrument.html)         |                Enable instruments                 |
|             [`ps_setup_enable_thread()`](sys-ps-setup-enable-thread.html)             |         Enable instrumentation for thread         |
|              [`ps_setup_reload_saved()`](sys-ps-setup-reload-saved.html)              |   Reload saved Performance Schema configuration   |
|          [`ps_setup_reset_to_default()`](sys-ps-setup-reset-to-default.html)          |   Reset saved Performance Schema configuration    |
|                      [`ps_setup_save()`](sys-ps-setup-save.html)                      |       Save Performance Schema configuration       |
|             [`ps_setup_show_disabled()`](sys-ps-setup-show-disabled.html)             | Display disabled Performance Schema configuration |
|   [`ps_setup_show_disabled_consumers()`](sys-ps-setup-show-disabled-consumers.html)   |   Display disabled Performance Schema consumers   |
| [`ps_setup_show_disabled_instruments()`](sys-ps-setup-show-disabled-instruments.html) |  Display disabled Performance Schema instruments  |
|              [`ps_setup_show_enabled()`](sys-ps-setup-show-enabled.html)              | Display enabled Performance Schema configuration  |
|    [`ps_setup_show_enabled_consumers()`](sys-ps-setup-show-enabled-consumers.html)    |   Display enabled Performance Schema consumers    |
|  [`ps_setup_show_enabled_instruments()`](sys-ps-setup-show-enabled-instruments.html)  |  Display enabled Performance Schema instruments   |
| [`ps_statement_avg_latency_histogram()`](sys-ps-statement-avg-latency-histogram.html) |        Display statement latency histogram        |
|          [`ps_trace_statement_digest()`](sys-ps-trace-statement-digest.html)          |Trace Performance Schema instrumentation for digest|
|                    [`ps_trace_thread()`](sys-ps-trace-thread.html)                    |      Dump Performance Schema data for thread      |
|             [`ps_truncate_all_tables()`](sys-ps-truncate-all-tables.html)             |    Truncate Performance Schema summary tables     |
|     [`statement_performance_analyzer()`](sys-statement-performance-analyzer.html)     |      Report of statements running on server       |
|                       [`table_exists()`](sys-table-exists.html)                       |              Whether a table exists               |

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**Table 28.4 sys Schema Stored Functions**

|                                  Function Name                                  |                              Description                              |Deprecated|
|---------------------------------------------------------------------------------|-----------------------------------------------------------------------|----------|
|   [`extract_schema_from_file_name()`](sys-extract-schema-from-file-name.html)   |                 Extract schema name part of file name                 |          |
|    [`extract_table_from_file_name()`](sys-extract-table-from-file-name.html)    |                 Extract table name part of file name                  |          |
|                    [`format_bytes()`](sys-format-bytes.html)                    |                Convert byte count to value with units                 |  8.0.16  |
|                     [`format_path()`](sys-format-path.html)                     | Replace directories in path name with symbolic system variable names  |          |
|                [`format_statement()`](sys-format-statement.html)                |                Truncate long statement to fixed length                |          |
|                     [`format_time()`](sys-format-time.html)                     |             Convert picoseconds time to value with units              |  8.0.16  |
|                        [`list_add()`](sys-list-add.html)                        |                           Add item to list                            |          |
|                       [`list_drop()`](sys-list-drop.html)                       |                         Remove item from list                         |          |
|           [`ps_is_account_enabled()`](sys-ps-is-account-enabled.html)           |   Whether Performance Schema instrumentation for account is enabled   |          |
|          [`ps_is_consumer_enabled()`](sys-ps-is-consumer-enabled.html)          |            Whether Performance Schema consumer is enabled             |          |
|[`ps_is_instrument_default_enabled()`](sys-ps-is-instrument-default-enabled.html)|      Whether Performance Schema instrument is enabled by default      |          |
|  [`ps_is_instrument_default_timed()`](sys-ps-is-instrument-default-timed.html)  |       Whether Performance Schema instrument is timed by default       |          |
|       [`ps_is_thread_instrumented()`](sys-ps-is-thread-instrumented.html)       |Whether Performance Schema instrumentation for connection ID is enabled|          |
|               [`ps_thread_account()`](sys-ps-thread-account.html)               |         Account associated with Performance Schema thread ID          |          |
|                    [`ps_thread_id()`](sys-ps-thread-id.html)                    |      Performance Schema thread ID associated with connection ID       |  8.0.16  |
|                 [`ps_thread_stack()`](sys-ps-thread-stack.html)                 |                  Event information for connection ID                  |          |
|              [`ps_thread_trx_info()`](sys-ps-thread-trx-info.html)              |                 Transaction information for thread ID                 |          |
|                [`quote_identifier()`](sys-quote-identifier.html)                |                      Quote string as identifier                       |          |
|                  [`sys_get_config()`](sys-sys-get-config.html)                  |                 sys schema configuration option value                 |          |
|                   [`version_major()`](sys-version-major.html)                   |                   MySQL server major version number                   |          |
|                   [`version_minor()`](sys-version-minor.html)                   |                   MySQL server minor version number                   |          |
|                   [`version_patch()`](sys-version-patch.html)                   |               MySQL server patch release version number               |          |

